Hand injuries

Hand injuries

HAND GENERAL PRINCIPLES ANATOMY OF THE FOREARM INJURIES AND HAND It is imperative to have a basic knowledge of the anatomy of the forearm and...

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HAND

GENERAL

PRINCIPLES

ANATOMY

OF THE

FOREARM

INJURIES

AND

HAND

It is imperative to have a basic knowledge of the anatomy of the forearm and hand before engaging in the management of hand injuries. A cursory review is presented, but it is assumed that the reader will obtain a working knowledge of the anatomy from standard texts. Muscles

The most superficial volar layer of the muscles that arise from the medial epicondyle of the humerus includes the pronator teres, flexor carpi radialis, palmaris longus, and flexor carpi ulnaris muscles (Fig. 1). Laterally, the brachioradialis and extensor carpi radialis longus muscles arise from the humerus. When these two groups of muscles are reflected, the flexor digitorum superficialis muscle is exposed. The flexor pollicis longus muscle is lateral to the superficialis muscle. The flexor digitorum profundus muscle is deep to the superticialis. The pronator quadratus is exposed in the distal forearm when the profundus tendons are reflected (Fig. 2). Muscles within the hand that are innervated by the median nerve include the thenar muscles (abductor pollicis brevis, opponens pollicis, and flexor pollicis brevis) and the lumbrical muscles to the index and long fingers (Fig. 3). The ulnar nerve supplies the hypothenar muscles (abductor digiti minimi, flexor digiti minimi, and opponens digiti minimi), the lumbricales to the ring and little fingers, and the interosseous muscles. The flexor tendons are contained within a specialized digital sheath extending from the distal palmar crease to the distal phalanx of each of the fingers and from the metacarpophalangeal joint crease of the thumb to the distal phalanx (Fig. 4). The sheath will be described in detail later. The extensor muscles arising from the lateral epicondyle of the humerus include the extensor carpi radialis brevis, the extensor digitorum communis, the extensor digiti minimi, and extensor carpi ulnaris (Fig. 5). When these muscles are reflected, the supinator muscle is exposed proximally and the deep muscles of the dorsal foreCur-r

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k

Intermuscular -Ulnar

Septum

Nerve

i.

Median

Nerve

Medial

Epicandyle

II-

Superficial

Brachiar

,adialis

Muscle

-

FIG. 1. The

Muscles

superficial

volar

forearm

muscles

arise

from

the medial

Bicipital

epicondyle

Apaneura

sis

of the hu-

merus.

734

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-Ulnar

Nerve Medion

Brachial

Artery

L

of Rodial

Pronator

Nerve

-

Brachialis

Muscle

Nerve

Teres

,,,,,,, GI‘OUP

1 &Superficial

U1lProfundus Flexor Longus

Pollicis Musclt

Ulnar Ilk

FIG. flexor

Curr

2. The deep group digitorum profundus,

Probl

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August

of volar forearm muscles includes and the pronator quadratus.

1993

Ulnar

the flexor

Muscle Nerve Artery

pollicus

longus,

the

735

Lumbr ~icolt Muscle

-L-Suptrficiol

Thtnor

Polmor Arch

Muscles Hypothtnor

Muscles

FIG. 3. The motor branch of the median nerve supplies the thenar muscles.

arm, including the abductor pollicis longus, extensor pollicis brevis, extensor pollicis longus, and extensor indicis proprius, are exposed distally (Fig. 6). The extensor tendons are in six compartments over the dorsum of the wrist (Fig. 71. The extensor apparatus is formed by the extensor tendon at the level of the metacarpophalangeal joint and the lateral bands contributed by the lumbrical and interosseous muscles. This forms the extensor hood, which narrows at the level of the proximal interphalangeal (PIP) joint. The extensor tendon sends a slip to the base of the proximal phalanx and to the dorsal lip of the middle phalanx. More distally, the lateral bands continue over the middle phalanx to insert into the distal phalanx. Nerves The median nerve enters the forearm on the medial aspect of the elbow anterior to the intermuscular septum of the arm and medial 736

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Transverse Carpal Ligament

FIG. 4. The flexor tendon pulley system includes the transverse carpal ligament and a specialized system of annular (A) and cruciate (C) pulleys extending from the distal palmar crease to the distal phalanx.

epicondyle of the humerus (Fig. 1). The nerve passes beneath the bicipital aponeurosis, penetrates the pronator teres muscle, and emerges deep to the free edge of the proximal attachment of the superficialis muscle. The median nerve continues distally beneath the superficialis muscle to enter the carpal tunnel lateral to the superticialis tendons. In the forearm, branches from the median nerve innervate the pronator teres and the superficialis muscle before giving rise to the anterior interosseous nerve, which supplies the flexor pollicis longus, the index profundus, and the pronator quadratus. The palmar sensory branch arises on the radial side of the median nerve 6 cm proximal to the carpal canal. It enters the transverse carpal ligament radial to the median nerve to provide sensation in the palm. In the palm, the median nerve divides into a recurrent motor branch and sensory branches to the skin of the thumb, index, and long fingers, and to the radial side of the ring finger. The ulnar nerve is posterior to the intermuscular septum in the distal arm. It traverses the cubital tunnel, formed in part by the medial epicondyle of the humerus, to pass between the two heads of the flexor carpi ulnaris muscle (Fig. 2). The ulnar nerve continues distally beneath the flexor carpi ulnaris muscle to the wrist, where it enters the canal le Guyon. Here it divides into a superficial sensory branch and a deep motor branch. The motor branch penetrates the arcade formed by the opponens digiti minimi and flexor digiti minimi brevis muscles. It extends across the palm deep to the flexor tendons to supply the interosseous muscles and lumbricales of the ring and little fingers. Its terminal branches innervate the first dorsal interosseous and deep head of the adductor pollicis muscles. In the distal arm, the radial nerve exits the spiral groove beneath the brachioradialis muscle. Branches innervate the brachioradialis and the extensor carpi radialis longus muscle. At the elbow, the radial nerve divides into a superficial and a deep branch (Fig. 2). The Cur-r Probl

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737

Brachioradiolis

Lateral

Extensor

Extensor

Muscles

Epicondyle

4

Carpi RadialisLongus Muscle

Carpi Radiolis Brevis Muscle

-Ulna

A Y Extensor Communis

FIG. 5. The extensor the dorsal

forearm,

tendons arise from the distal humerus, including the radius, ulna, and interosseous

the lateral septum.

Digitorum Muscle

epicondyle,

and

superficial branch continues distally beneath the brachioradialis muscle. The deep branch enters the forearm beneath the supinator muscle. On exiting the supinator muscle on the dorsum of the forearm, it innervates the extensor muscles (Fig. 6). The brachial artery accompanies the median nerve in the distal arm 738

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Rod ial Nerve Supinator

-B

Muscle

. Extensor Digit Communis Muscle Abductor Longus

Pollicis Muscle

Extensor Brevis

FIG. 6. The posterior beneath

the supinator

Pollicis Muscle

interosseous to innervate

!nsor

nerve (deep branch the thumb and finger

Pollicis

of the radial nerve) extensor muscles.

emerges

from

(Fig. 1). At the elbow, it lies anterior and lateral to the median nerve. In the proximal forearm, the brachial artery divides into the radial and ulnar arteries. The ulnar artery accompanies the median nerve beneath the superficialis arcade before turning toward the ulna to accompany the ulnar nerve distally. The ulnar artery traverses the Curr

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Extensor Extensor Extensor

corpi

Digiti

Extensor

Carpi Rodiolis Brevis

Minimi

ulnoris Abductor

FIG.

7. The

extensor

tendons

are contained

in six compartments

about

Pollicis Longus

the dorsal

wrist.

canal le Guyon and forms the superficial vascular arch and common digital arteries in the hand (Fig. 3). The radial artery turns laterally to lie beneath the brachioradialis muscle and anterior to the pronator teres muscle. It becomes superficial at the wrist before coursing dorsally through the snuff box to appear on the dorsum of the hand. The radial artery penetrates the thumb-index finger web space to contribute to the deep vascular arch. It has branches that communicate with the superficial vascular arch formed by the ulnar artery.

Joint Ligaments The joints are stabilized by collateral ligaments and palmar plates. The metacarpophalangeal (MP) joint has a large collateral ligament on each side of the joint that is lax in extension and taut in flexion (Fig. 8). The volar plate attaches to the volar lip of the proximal phalanx and to loose areolar tissue proximally, permitting hyperextension of the MP joint. The volar plate of the PIP joint attaches to the proximal phalanx and to the volar lip of the middle phalanx restricting extension. A similar arrangement is present at the distal interphalangeal (DIP) joint. The thumb is unique in its wide range of motion. The anterior oblique ligament provides great mobility but prevents dislocation. At the carpometacarpal joint of the fifth finger, a similar arrangement is present. The wrist bones are stabilized by extrinsic and intrinsic ligaments (Fig. 9). The extrinsic ligaments connect the radius or ulna and the carpal bones. The intrinsic ligaments connect carpal bones. These ligaments maintain congruity of the articular surfaces. When these ligaments are disrupted, the carpal bones move in discord, and may result in traumatic arthritis.

Skin Palmar skin is attached to the underlying palmar fascia by septa, which anchor the skin to the fascia stabilizing the skin. The palmar 740

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FIG. 8. A, The collateral

ligaments are taut in flexion and lax in extension. The volar does not restrict MP joint (Jr) extension. B, The volar plate limits PIP joint extension, collateral ligaments stabilize the joint laterally.

FIG. 9. The extrinsic ligaments the carpal bones. The intrinsic

Curr

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(Lj of the wrist arise ligaments attach one

on the radius and ulna carpal bone to another.

and

plate The

attach

to

741

fascia is attached to the metacarpals through vertical extensions. mar skin movement is thereby minimized to improve grasp.

Pal-

Venous Drainage The major venous drainage of the hand is through the cephalic and basilic veins on the dorsum of the hand. The cephalic vein courses around the lateral side of the forearm to the elbow. The basilic vein courses around the medial side of the forearm to the elbow, where the two veins communicate by the median cubital vein. The cephalic vein traverses the arm on the lateral aspect of the biceps muscle and the basilic vein follows the brachial artery.

INITIAL MAA’AGEMENT Industrial workers should be instructed in first aid for upper extremity injuries, the most common injuries seen in emergency medicine. This includes techniques for controlling bleeding, removal of finger rings if possible, splinting the injured part, prevention of further contamination of the wound, and preparing the patient and all amputated parts for transportation to an emergency department. Bleeding is usually controlled by elevation of the extremity and application of a bulky dressing. If bleeding persists, as with partial laceration of an artery, direct pressure over the vessel should be applied by an individual accompanying the patient to the hospital or a tourniquet should be used for a short period. The rapid onset of swelling necessitates the removal of finger rings as quickly as possible. While the patient is being transported, support of the injured hand is provided with sterile gauze dressings wrapped about a rigid splint. No attempts should be made to cleanse the wound or apply an antiseptic. If a portion of the extremity has been detached, all detached parts should be placed in a sealed plastic bag placed inside a second plastic bag containing more water than ice. The parts must not be frozen, nor should they ever be in direct contact with the ice-water solution. With major amputations, such as at the mid arm level, the brachial artery will retract and bleeding will cease. If this does not occur, judicious use of a tourniquet is indicated. The amputated extremity is placed in a bag, which can be placed in a cooler. If a cooler is not available, a large plastic bag is adequate. Keeping major amputated parts cool is extremely important. To ensure that the patient and the part arrive at the same hospital, amputated parts must accompany the patient and should not be entrusted to another party.

Emergency

Department

Management

The primary goals in the emergency department ing complete historical information, (2) examining

include (1) obtainthe injury and de-

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termining its severity, (3) obtaining diagnostic studies as indicated (e.g., roentgenograms), and (4) determining whether definitive care can be accomplished in the emergency department, the operating room, or at another facility. If definitive care is to be provided at another hospital, it is most important that the physician eliminate the possibility of concomitant life-threatening injuries. Patients have died from unsuspected internal injuries while being transported for limb replantation. If the injury is limited to the upper extremity and transfer to another hospital is anticipated, the only reasons to inspect the wounds are to control bleeding and to make sure that partially amputated or unstable parts are supported in the optimum position to maintain blood flow. A history of tetanus immunization should be obtained from every patient with a wound. The American College of Surgeons has established guidelines for tetanus prophylaxis and immunization (Table l).l The use of prophylactic antibiotics is controversial. If antibiotics are used, selection is dependent on the organisms suspected from the circumstances of the injury (Table 21.’ Cultures should be obtained and sensitivity studies should be ordered. History It is important to determine from the patient or a coworker the mechanism of injury (e.g., crushing, lacerating, or compressive) and whether heat or cold was involved. Was the causative agent broken glass, a bite, injection fluid, firearm, pulley belt, or another factor? The circumstances surrounding the injury may contribute to contamination (e.g., working in a greasy environment). Physical Examination The surgeon who will render definitive care should inspect the wound in the emergency department, wearing a mask and sterile gloves. Cursory examination and observation of the injured part can provide significant information. In an extensively damaged extremity, patient cooperation may be limited because of pain and apprehension. Sensory testing (e.g., two-point discrimination) may be futile, but response to light touch can be evaluated. Active motion is determined by having a patient mimic the examiner’s hand movements. During this initial contact, the patient determines confidence in the surgeon. The surgeon should avoid comments and facial expressions that can be misinterpreted by the patient. The surgeon must minimize testing that significantly increases the patient’s anxiety and yields little useful information. In most instances, the patient’s livelihood depends upon use of his or her hands; consequently, anxiety is well founded. The surgeon should answer all questions directly and should not generate undue optimism or pessiCur-r

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TABLE

1. Tetanus

Type of Wound Clean

minor

Clean major or tetanus prone

Pruuhvlaxis Patient Not Immunized Partially Immunized

Patient Years

or

Begin or complete immunization per schedule; tetanus toxoid 0.5 ml In one arm: human tetanus immune globulin 250

Completely Since Last

Immunized, Booster Dose

1 to .5*

5 to 10

None

Tetanus toxoid ml

0.5

Tetanus toxoid ml

0.5

Tetanus toxoid ml

0.5

210

Tetanus toxoid ml

In one arm: tetanus toxoid 0.5 mlt

m@ In other arm: tetanus toxoid 0.5 ml,t complete immunization

Tetanus prone delayed, or incomplete debridement

per schedule In one arm: human tetanus immune globulin 500 me? In other arm: tetanus toxoid 0.5 ml,t complete immunization

0.5

In other arm: human tetanus immune globulin 250 w+

Tetanus toxoid mlt

0.5

Tetanus toxoid ml

In one arm: tetanus toxoid 0.5 mlt

0.5

Antibiotic therapy

In other arm: human tetanus immune globulin 500 wt

per schedule thereafter Antibiotic therapy

Antibiotic therapy

Fmm American College of Surgeons. Early care of the injured patient. 2nd ed. Philadelphia: WB Saunders, 1976. Note: With different preparations of toxoid, the volume of a single booster dose should be modified as stated on the package label. *No prophylactic immunization is required if patient has had a booster within the previous year. tUse different syringes, needles, and sites.

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TABLE

2. Prophylactic

Antibiotic

Selection Antimicrobial

Most

Iniurv

Trauma

Lkelv

Bacteria

Staphylococcus

Primarv

aureus,

Alternative

AM/CL

or cefoxitin

streptococci Human

bite

Streptococcus Pup

viridans,

*

streptococci, staphylococcus

A,

Eickenella corrodens, Bacteroides Fusobacterium

Cat bite

Pasteurella

Dog bite

Streptococcus

\_

sp.

vi&fans,

Pasteurella multocida,

Rat bite

AM/CL preferred. Penicillin V, ampicillin, or clindamycin often used

Oral first-generation cephalosporin Cefotoxin or erythromycin

sp.,

multocida

Bacteroides Fusobacterium Streptobacillus moniliformis

Therapy

Penicillin

V

Penicillin V or ampicillin

Ceftriaxone or tetracycline Tetracycline, AM/CL, or ceftriaxone

Ampicillin

Tetracycline

sp., sp.

Modified fmm Sanford JP. Guide to antimicrobial Reproduced with permission. AM/CL, Amoxicillin clavulanate.

therapy.

Dallas: Antimicrobial

Therapy,

Inc., 1993:31-z.

mism. If the surgeon believes that a part is damaged beyond salvage, this should be discussed with patient and family, with an explanation as to why an amputation may be necessary. A lengthy explanation of the surgery required may be quickly forgotten by the patient.

Roentgenographic

Evaluation

Roentgenographic evaluation is best directed by a thorough history and physical examination. Adequate evaluation of the fingers requires posteroanterior, oblique, and lateral views. The fingers must be spread in a cascade fashion to profile the bones and joints. If the lateral view does not profile the phalanges and metacarpals, a volar chip fracture may be missed. If the fingers are flexed on the oblique view, the middle and distal phalanges will be foreshortened, with overlapping of the interphalangeal joints. Positioning of the hand in the oblique position so that the fingers are extended prevents foreshortening of the phalanges and interphalangeal joints. Hand views include the wrist; however, penetration of the hand may be inadequate for accurate evaluation of the wrist. A routine wrist examination includes posteroanterior, oblique, lateral, and scaphoid views. The posteroanterior view should be taken with the palm flat on the table. If the palm is not flat on the roentgenographic film, the carpometacarpal joints Cur-r Probl

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745

will be extended and will not be profiled adequately. The lateral view should be obtained with the wrist in the neutral position to evaluate carpal bone alignment. If there is evidence of a static or dynamic instability, further studies may be needed, such as fluoroscopy and arthrograms. If history and physical examination are highly suggestive of a fracture and roentgenograms are unrevealing, a bone scan should be obtained because this test is virtually specific for detecting recent fractures3 Falling on the outstretched hand can produce elbow injuries, such as a radial head fracture, and this possibility must not be overlooked. When replantation is anticipated, the amputated parts and the involved extremity should be evaluated roentgenographically. Establishing Priorities Injuries of the upper extremity are rarely life-threatening, yet the disability from the residual functional loss can profoundly alter a patient’s life. The treatment plan should be discussed with the patient during the initial encounter in the emergency department if the situation permits. Unfortunately, the patient is usually so distraught as to be unable to comprehend any discussion in depth. If family members are available, treatment options can be discussed with them. In mutilating injuries, preservation of as much functional tissue as possible can permit formation of a basic hand.4 The basic hand is composed of a mobile sensate radial digit separated by a cleft from an ulnar post. A minimum of parts is needed, and the patient much prefers this to a prosthesis. After a cursory examination of the hand, each part is evaluated in a systematic fashion to determine the extent of injury and the functional capacity of each digit. In the past, definitive reconstructive procedures were not routinely performed during the initial treatment. These procedures have become more routine with improvements in instrumentation, techniques, and experience. The decision to salvage a part that is useless, either in its original role or as a contributor to restoration of another part, is unsound. Making these decisions places significant responsibility on the surgeon. In evaluating a severely injured hand, the surgeon must be able to decide whether a part is of value and must be aware of the techniques available for reconstruction or utilization of an injured part as a contributor to restoration of another part. The surgeon must therefore be current in the techniques of replantation, amputation, delay, observation, decompression, and reconstructive surgery. The background required to select the proper technique and follow it through to its technical completion has created the specialty of hand surgery. Our method of management of the acutely injured hand is tissue oriented, both for evaluation and for subsequent treatment. If this simple technique is followed, few injuries are overlooked. This approach yields the maximal functional result. The scheme first evalu746

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ates injury to the vasculature, then to skin, nerve, tendons, bones, and joints. Vascular compromise is obvious with an amputation. When a part is still attached, however, is it adequately perfused and, if not, is revascularization indicated? These decisions require judgement, which, unfortunately, is based on experience gained by making both good and bad decisions. Management Scheme The initial management of the injured hand in which an adequate blood supply has been preserved is directed toward restoration of functional units, obtaining healing with minimal scar formation, and providing an optimum environment for subsequent surgery if necessary. A systematic evaluation of the injured tissues provides an accurate assessment of damage. This examination is tissue oriented, as is the surgical reconstruction, beginning with skin and progressing through nerve, tendon, bones, and joints. By means of this simple systematic evaluation, the chances of overlooking an injury are minimized. First, is there skin loss? If the skin envelope. is intact, the exact mechanism of injury is even more important. The position of the hand, the forces involved, how the forces were applied, how long, and what was done by the patient or coworkers to extract the hand must be considered. What agents (e.g., heat, cold, compression) were involved? A fall on the outstretched hand or a spinning steering wheel produces classic ligamentous and bony injuries. The physical forces and agents involved provide clues as to which structures are involved and to what extent. With a closed injury, the development of Volkmann’s ischemic contracture in the forearm or hand is of particular concern5 Indicators of a poor prognosis include pain on finger extension, paresthesia, lack of pulse, pallor, and paralysis. Repeated examinations are necessary to detect Volkmann’s contracture early after onset and provide remedial treatment before disastrous results occur. Direct measure of compartmental pressure with a wick catheter is recommended in suspected cases, especially with an associated brachial plexus injury or in an unresponsive patient. Pressures in the volar compartment of the forearm are determined by inserting the catheter at the junction of the middle and proximal third in the volar midline. The dorsal compartmental pressure is determined at the same level. A 16 gauge catheter is directed distally through the fascia and into the muscle. The central trocar is removed, leaving the plastic cannula in place as a guide. The transducer system is calibrated and a saline-filled wick catheter is inserted through the cannula into the muscle compartment. The plastic cannula is removed. If the patient contracts the muscles in the compartment being tested, a significant rise in pressure should be noted. Resting intracompartmental pressures are determined. Decompression is indicated if the clinical examination is Curr

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suggestive of compartmental syndrome and the pressure measurements are greater than 30 mm Hg6 If the skin is lacerated or avulsed, the status of the wound must be evaluated, Thorough cleansing is necessary. Grease can be removed with commercial degreasers or antibiotic ointment. After the skin has been cleansed, the wound must be thoroughly irrigated. Fine particles of grease and emery dust associated with many industrial accidents evoke an intense inflammatory reaction, producing fibrosis that interferes significantly with subsequent restorative procedures. Simple irrigation helps remove debris and can remove up to 90% of the surface bacteria. This reduces the bacterial count but is ineffective in heavily contaminated wounds. Irrigation of this type of wound is best accomplished by means of a pulsating water-jet apparatus, with normal saline solution at a pressure of 7 to 10 pounds per square inch. The extent of contamination determines the amount of irrigant needed. If irrigation is ineffective, the soft tissues must be excised to remove the foreign material. Disinfectants can kill tissue. The toxicities of four antimicrobial agents on both Staphylococcus aureus and cultured fibroblasts have been reported.7 Agents including hydrogen peroxide, acetic acid, povidone-iodine, and sodium hypochlorite were extremely toxic to tissues at full strength. Through serial dilutions, hydrogen peroxide and acetic acid lost bacterial toxicity before they lost fibroblastic toxicity. Dilutions of povidone-iodine to 1: 1000 and of sodium hypochlorite to 1: 100 were required before these agents lost fibroblastic toxicity. Antibacterial activity persisted even at these dilutions. Many techniques for preparing the skin have been reported. Most antiseptic solutions include pure alcohol and hexachlorophene (pHisoHex). Alcohol is an excellent skin disinfectant, although its antiseptic properties are short-lived. Iodine solutions, either iodine in alcohol or aqueous iodine solutions, are commonly used. Iodoforms that contain povidone-iodine are also commonly used. Chlorhexidine (Hibiclens) is a 70% alcohol solution that has gained favor. Each solution has advantages and disadvantages. Common disadvantages include skin irritation or allergic reactions from the iodine. In clean, elective upper extremity cases, I use an iodine-alcohol solution, which works effectively for skin antisepsis and has a low rate of skin irritation. Povidone-iodine (Betadine) is preferred for contaminated or open wounds. Limited excision of the wound edges is necessary in sharply lacerated wounds. A crush injury devitalizes tissue, and the wound edges must be excised. Extension of the area of devitalized tissue may occur after a blunt injury in the first few postoperative days, thus requiring a “second look” at the wound after 24 hours. Determining muscle viability can be difficult. The best indicator of viability is bleeding during debridement. In general, the tourniquet is inflated to con748

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trol bleeding and aid in exploration, so we frequently deflate the tourniquet during muscle debridement to assess viability. Repeat wound examination in the early postoperative period is mandatory when muscle damage is suspected. Most surgeons agree that a clean wound should be closed at the initial treatment. It is difficult to determine the extent of tissue destruction when there is extensive injury to the hand (e.g., a crush injury). If the wound is covered with a pedicle flap, extensive infection developing beneath the flap may remain undetected for several days. Consequently, we prefer thorough debridement and application of a large bulky hand dressing with indwelling catheters on the surface of the wound for irrigation and inspection of the wound at 24 to 48 hours after injury. When the wound has been adequately debrided, definitive coverage is accomplished. If the wound is not clean, it is debrided and closure is delayed. The use of antibiotics in the contaminated wound is routine but controversial. The most appropriate tissue coverage is selected only after thorough debridement.

OPERATlVE MANAGEMENT Choice of Anesthetics in Hand Surgery Local, intravenous regional, regional block, and general anesthesia may be used. The advantages and disadvantages from the surgeon’s standpoint are listed in Table 3. The patient’s age and general health, presence of associated injuries, anticipated extent of the operative procedure, history of drug allergies, and recent ingestion of food influence anesthetic agent selection. If the patient has coronary artery disease, chronic obstructive airway disease, or compromised hepatic or renal function, local, intravenous regional, or regional block may be safer than general anesthesia. A young child always requires general anesthesia. Pneumatic Tourniquet A pneumatic tourniquet may be used to provide a bloodless field. The complications associated with the use of a tourniquet include (1) tissue necrosis from prolonged ischemia, (2) nerve palsy, usually related to use of a faulty tourniquet, and (3) burns to the skin of the arm from preparatory solution beneath the tourniquet. Calibration of the tourniquet must be performed each day in the operating room with a mercury manometer. Safety valves have been installed in some models to prevent excessive pressure. Padding is used beneath the tourniquet to distribute the pressure more evenly in the arm and to avoid pinching the skin. Preparatory solution burns to the skin of the arm beneath the tourniquet can be avoided by placing a towel around the distal edge of the tourniquet to prevent the solution from soakCurr

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TABLE

3. Choice

Local

Intravenous

regional

of Anesthesia

in Acute

Disadvantages

1. Ease of administration 2. Rapid onset

1. Arm tourniquet 2. Inflamed tissues difficult to anesthetize 3. Field limited

3. Unlimited finger tourniquet time 1. Ease of administration 2. Rapid

Regional

General

block

tnjuries

Advantages

1. Tourniquet pain after 1 hour 2. Tourniquet cannot be deflated during procedure 3. Tissues may ooze continuously 1. Slow onset

onset

1. Motor and sensory inhibition 2. Tourniquet pain free for 2 to 4 hours

2. Variable

3. Tourniquet pain 4. Operator-dependent success 5. Time required to administer 6. Neuritis 1. Induction complications (e.g., aspiration)

1. No tourniquet

2. Rapid onset 3. Tourniquet can be inflated and deflated often as needed 4. Other areas accessible for grafts, flaps

success

as

ing into the padding beneath the tourniquet while the extremity is being prepared. How long can the tourniquet safely be left inflated? Suggestions vary from 45 minutes to 4 hours, with 2 hours being the most widely accepted time. After tourniquet inflation, venous blood pH in the forearm drops from 7.4 to 7.31, 7.19, 7.04, and 6.90 at 30, 60, 90, and 120 minutes, respectively, after inflation.’ Concomitantly, the partial pressure of oxygen falls from 45 mm Hg to 20, 10, and 4 mm Hg at 60, 90, and 120 minutes, respectively, of ischemia. After 2 hours, physical abnormalities have been reported in the muscles. The following recommendations are made: (1) Minimize tourniquet time. (2) A single application should not exceed 2 hours. (3) After deflating the tourniquet, keep it deflated 5 minutes for every 30 minutes of inflation time before reinflating it. (4) Oozing associated with tourniquet 750

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release will usually decrease as arteriovenous with acidosis subsides. (5) Calibrate tourniquet SKIN

shunting pressures

associated every day.

INJURIES

WOUNDS OF SKIN

REQUIRING COVERAGE

SKIN

COVERAGE:

SELECTION

Two types of coverage are available: (1) skin grafts consisting of epidermis and dermis (split- and full-thickness) and (2) vascular grafts consisting of any combination of tissue units, including skin, subcutaneous tissue, bone, nerve, joint, tendon, or fascia. Vascular grafts may be pedicle or free grafts. Skin grafts have no discrete blood supply and therefore must obtain nourishment from the recipient site. The dermis of the skin graft must therefore be in intimate contact with the recipient site. The dense collagen in the dermal layer of splitor full-thickness skin grafts adheres to the underlying structures, rendering them immobile. Graft selection is determined by evaluation of the base of the wound and the functional requirements of the injured region (Table 4). Because skin grafts render underlying structures immobile, they are undesirable over an exposed tendon. However, skin grafts are selected to cover subcutaneous tissue, granulation tissue, muscle, bone with periosteum, and tendon with paratenon (Fig. 10). The free full-thickness skin graft is most often used in clean, acute wounds in which function requires extra padding (e.g., digital pulp or palmar area) and where the recipient bed is subcutaneous tissue. Vascularized grafts are used when bare tendon is exposed, tendon gliding is required over joints, or joint movement is required, and over open joints, major blood vessels and nerves, and places in which padding is desirable. If vascular graft coverage is required in the upper extremity, the advantages and disadvantages of each type of graft must be considered !Table 5). The vascularized flap may be either a pedicle or free flap. The pedicle skin flap consists of epidermis, dermis, and subcutaneous tissue TABLE Area

4. tissue Coverage Selection

of Tissue

Loss

Preferred

Finger pulp (limited) Finger pulp (extensive) Finger, ring avulsion Finger, volar or dorsal only Hand, palm or dorsum Wrist, palmar or dorsal surfaces Forearm, volar or dorsal *Only if split- or full-thickness Curr

Probl

SW..

August

Local sensate flaps (V-Y) Toe pulp free flap Toe wrap-free flap Tempo&is-free flap Temporalis-he flap Temporalis-kee flap Pedicle flap, free flap-groin, temporalis

skin graft is contraindicated 1993

Coverage*

lateral

arm,

or

bee text). 751

FIG. 10. A third-degree covered with a skin graft.

burn

without

involvement

of the

paratenon

can

be excised

and

that maintains continuity with the donor area during transfer and in the early healing phase. Later, its base is divided and set into the recipient site. A free flap, which has a single artery and vein providing its circulation, is completely detached from the donor area and transferred to the recipient site, where a vascular anastomosis is required. Because a vascular flap has its own blood supply, any combination of subcutaneous, neural, and bony tissues can be transferred with the flap. In fact, a spectrum of flaps is possible, extending from TABLE

5.

Temporal

Flap

fascia

Radial forearm free)

Lateral

752

arm

Selection

Factors

(free)

ipedicle

or

Advantages

Disadvantages

1. Thin 2. Morbidity minimal 3. Donor scar concealed 4. Can be flow-through 5. Pliability 1. In operative field 2. Dissection simple 3. Reliable 4. Thin distally

1. Time extended 2. Dissection tedious 3. Anatomy variable

1. Can be sensate 2. Donor site may be closed if less than 6 cm wide

1. 2. 3. 4. 5. 6.

Thick proximally Donor defect morbidity Major vessel sacrificed Cannot be double-teamed Extensive incisions Not available if ulnrir artery occluded 1. Grafted donor site poor 2. Flap thick and bulky

Curr

Probl

Surg,

August

1993

a simple broad flap of skin containing numerous fine capillaries to a flap containing all of the digital components served by a single artery and vein. The subcutaneous fat of the pedicle graft evokes minimal scar formation by the recipient bed. Dense scarring occurs primarily at the periphery of the flap, where the dermis of the flap and the recipient site abut. Vascularized flaps are used when local tissue loss precludes adequate coverage of tendons, bone, joints, and major neurovascular elements. The sine qua non for functional recovery is tendon gliding and joint suppleness. Tendons are encircled by a specialized structure, the paratenon, which aids gliding. Free skin grafts applied to paratenon do not interfere with tendon gliding, but when the paratenon has been lost, vascularized flap coverage becomes necessary (Fig. 11). Exposed tendon covered with a pedicle flap evokes less scarring about the tendon. Exposed bone that is or has been traversed by tendon units requires vascularized flap coverage, anticipating later restoration of tendon gliding through the area. Periosteum readily accepts a split graft; if tendon grafting, repair, or transfer is anticipated in that area, however, the split graft will not provide an adequate gliding surface for tendons. An exposed joint in the hand, wrist, or elbow must be closed with a vascularized flap if joint mobility is to be preserved (Fig. 12). The exposed joint is positioned to maximize the tissue defect and, consequently, the amount of vascularized tissue inserted. The surgeon should be versed in the variety of flaps available to ensure optimum wound coverage.

NERVE

INJURIES

NERVE

INJURY

The structural anatomy of the peripheral nerve must be clearly understood to manage nerve injuries. The neuron, which is the anatomic and functional unit of the peripheral nervous system, consists of a cell body, one axon, and multiple dendrites. The cell body of a motor neuron is located in the anterior horn of the corticospinal tract, whereas the nerve body of a sensory neuron is located in the dorsal root ganglia. The axon is ensheathed by Schwann cells, which may contain myelin. The axonal sheath, or endoneurium, is a connective tissue envelope surrounding an axon-Schwann cell complex. Its function is to resist stretching, maintain intraaxonal pressure, and serve as an insulator. The macroscopic unit of a peripheral nerve is the fascicle, or funiculus, consisting of a group of axons surrounded by a thin but durable sheath called perineurium (Fig. 13). The perineurium invests each fascicleg and serves to protect the axon against stress, act as a diffusion barrier, maintain intrafascicular pressure, and provide a barrier to the spread of infection. Most nerves are comCurrProblSurg,August1993

753

FIG. direct

11. An avulsion exposure

injury of the dorsum of the hand results of the extensor tendons. Pedicle flap coverage

in loss of paratenon is required.

and

posed of several fascicles. The fascicular pattern of the peripheral nerves in the upper extremity has been defined by computerized studies (Fig. 14) .l" The major connective tissue elements of the peripheral nerve include the epineurium, which is divided into an outer and inner layer, and the perineurium. The epineurium invests the 7.54

Cur-r Probl

Surg,

August

1993

FIG. 12. The extensor tendons avulsed. Pedicle flap coverage

and a portion is necessary.

of the carpals

and

metacarpals

have

been

peripheral nerve and consists of collagen fibers and elastin. The epineurium contributes to elasticity and tortuosity of the nerve, thus providing protection against stretching and compressive forces. In summary, a peripheral nerve consists of both neural elements (axons) and fibrous tissue elements (endoneurium, perineurium, and epineurium). REACTION

TO INJURY

Peripheral nerve injury results in changes in the cell body, the axon proximal and distal to the site of injury, and the functional units innervated (e.g., muscle and skin). The more proximal the peripheral nerve injury, the greater the cell damage. Cell body damage is evidenced by changes in both cell size and internal organization. After injury, the cell body progressively enlarges for approximately 20 days and then remains enlarged during the period of axon regeneration. When regeneration is complete, the cell body returns to normal size. If regeneration is prevented, the cell may atrophy. After a simple crush injury, nerve function returns within days and no cell loss occurs. If an injury causes division of the nerve close to the cell body, cell death occurs. After laceration, the proximal nerve stump swells, resulting in a threefold increase in its cross-sectional area. This edema forms in response to the accumulation of a gel-like amorphous substance containing a large quantity of acidic mucoCurr

Probl

Surg

August

1993

755

: FIG. 13. Cross-sectional anatomy of a peripheral (O-E), inner epineurium (I-E), and the perineurium encircled by an endoneurial sheath (ES).

O’E

(f)

nerve depicting of each fascicle

the outer epineurium (F). Each axon (A) is

FIG. 14. The fascicles of the thumb (From raphy Surg

756

have been coded according to fiber destination in a cross-section median nerve at the wrist. Blank, 3rd web space; black, thumb motor; crosshatch, skin radial; dots, index skin: circles, thumb skin ulna; verfical bars, long finger skin. Watchmaker GP, Gumucio C, Crandall E, Vannier M, Weeks DM. Fascicular topogof the median nerve: a computer based study to identify branching patterns. J Hand [Am] 1991 ;16:57 [with permission].)

Cur-r Probl

Surg,

&ust

1993

polysaccharide. The edema gradually subsides within weeks. Schwann cells begin proliferating 48 to 72 hours after injury and assume a phagocytic role. Axonal sprouting may begin within 96 hours. Mesenchymal cells proliferate within and around the nerve sheaths and begin collagen synthesis, which is prominent early after injury. The regenerating axons may become entangled in a disorganized clump of scar tissue to form a neuroma. Reaction in the distal stump parallels that seen in the proximal stump. There is early edema formation and extensive connective tissue proliferation. The neurilemmal cells exhibit increased DNA and RNA content. If the nerve ends are not reapproximated, these neurilemmal cells proliferate and form a glioma. The axons distal to the site of nerve laceration undergo Wallerian degeneration, characterized by axonal enlargement into an amorphous mass, breakdown of the axons, and Schwann cell ingestion of the fragmented myelin.‘l In more distal axons, the cellular debris is typically phagocytosed within 3 weeks, providing clean endoneural tubes for the advancement of regenerating axons. If axonal regeneration into the empty endoneural sheaths is delayed, these sheaths undergo shrinkage that becomes more severe with time. There are three basic injury patterns, based on the anatomic derangements caused by nerve injury.l’ Neuropraxia, the least severe injury, is characterized by a conduction block. There is no associated Wallerian degeneration, and complete recovery occurs within 3 to 6 weeks after injury. &onotmesis is a more severe injury, with disruption of the continuity of the axon and surrounding endoneurium. The perineurium and epineurium, however, remain intact. Wallerian degeneration occurs. Because the integrity of the perineurium and epineurium is maintained, recovery is generally good but may require 6 months. The most severe injury is neurotmesis, in which there is disruption of the axons, endoneurium, perineurium, and epineurium. Wallerian degeneration occurs. Recovery requires operative repair and the prognosis is variable, ranging from no recovery to nearly complete return of function. This classification has been expanded to include five degrees of injury.13 A first-degree injury produces a conduction block without anatomic interruption of the neural or fibrous elements. Recovery is complete within weeks. In a second-degree injury, axonal continuity is disrupted but the fibrous tissue pathways remain intact. Wallerian degeneration occurs and recovery is usually delayed. A third-degree injury is limited to the fascicle, with disruption of the axons and endoneurium but with the perineurium and epineurium remaining intact. With disruption of the endoneurium, sprouting axons may enter the wrong distal tubules, resulting in incomplete recovery. Fourthdegree injury occurs when the fascicles, including perineurium, are completely disrupted but the loose epineural tissues remain intact. Cur-r Probl

Surg,

August

1993

757

The chances for spontaneous recovery are minimal, and surgical repair is required. In a fifth-degree injury, the neural and fibrous tissues are completely disrupted and the nerve ends retract. Surgical repair is required for this degree of injury. The factors that determine eventual functional recovery of an injured nerve include (1) degree of injury, (2) age of the patient, (3) type of injury, (4) composition of the severed nerve trunk, (5) level of injury, (6) presence of associated injuries, and (7) the skill of the surgeon. A thorough history and physical examination will define the diagnosis of most nerve injuries. A complete history of when, where, and how the injury occurred provides the basis for further evaluation, Physical examination includes observation of the extremity to determine the injury site. On the basis of a thorough knowledge of the neuroanatomy of the upper extremity, the nerves at risk can be determined from the site of injury. Variations in the anatomy should be appreciated. A partial laceration of the nerve may present some difficulty in diagnosis, but the history and physical examination will clarify its presence. Sensory and motor function in the median, ulnar, and radial nerves in the upper extremity should be thoroughly evaluated. Sensation is tested by determining static and moving twopoint discrimination. Although it is often recommended that a 256 Hz tuning fork be used to test sensation, patient cooperation is usually inadequate for sophisticated sensory testing in the acute injury situation.14 Disagreement concerning the appropriateness of primary versus secondary nerve repair has been resolved as the indications for each have become more clearly defined. In clean, sharp wounds, primary nerve repair is indicated. Several factors favor nerve repair at the time of acute injury. There will be less scarring. Dissection is minimized because the nerve ends have not retracted and become embedded in scar. One fewer operative procedure is required. Early repair facilitates early recovery of motor function. Both experimental and clinical studies have shown that primary repair of civilian-type nerve injuries in wounds converted to surgically clean wounds may be superior to secondary repair.15, l6

METHODS

OF REPAIR

Epineural nerve repair is considered the “gold standard” and has been the method of choice until recently. Epineural repair is designed to produce optimum coaptation and alignment without extensive dissection and suturing. By avoiding intraneural dissection and suturing, distortion of the internal anatomy of the nerve is minimized. Technically, the nerve ends are freed from the surrounding tissues 75s

Curr

Probl

Surg,

August

1993

and the damaged portion of each end of the nerve is resected. The vessels within the epineurium are identified to help in fascicular alignment. The nerve ends are rotated to align the epineural vascular and fascicular patterns. Under appropriate magnification, an epineural repair is performed with 10-O nylon suture. The suture should penetrate the epineurium but not disturb the perineurium. Inversion of the epineurium and perineurium must be avoided. Tension will result in gaps between the fascicles and excessive scar formation. More recently, however, fascicular .suture repairs using improved microsurgical techniques have been recommended as superior to epineural repairs (Fig. 15).17 This type of repair requires resection of the cut ends of the nerve back to normal nerve. The cross-sectional pattern of fascicles and epineural vessels in the proximal and distal ends is sketched. The fascicles are not dissected but are approximated with 10-O nylon sutures placed through the perineurium of each individual fascicle. Fascicular repair is possible only when a few fascicles are present. When there are more fascicles, a third type of repair, group fascicular repair, should be considered. A group of fascicles are dissected in the intraepineural plane under magnification.

Fqsicle

FIG. 15. With a fascicular Curr

Probl

Surg,

August

suture 1993

technique,

individual

fascicles

are aligned

and repaired. 759

The epineurium is gently teased from the surrounding fascicular bundles and each group is transected sharply. Each group of fascicles is approximated with 10-O nylon suture. When a segment of nerve has been lost or resection is necessary because of injury, the gap is bridged with a nerve graft. Nerve grafts are usually obtained from the sural nerve, located posterior to the lateral malleolus. Nerve grafting is also indicated when the fascicles cannot be approximated without tension by an epineural, interfascicular, or group fascicular repair technique. Occasionally, small nerve defects can be overcome by moderate joint flexion, nerve mobilization, or bone shortening, to permit nerve repair without tension. Bone shortening, of course, is applicable only in amputations, nonunions, or acute fractures. I prefer moderate flexion of the joints to nerve grafting if the nerve ends can be approximated without tension. Nerve grafts can be inserted either with an epineural method of repair or as interfascicular nerve grafts. The latter method is an exacting technique that should be undertaken only by surgeons who are well versed in microneurosurgery.

POSTOPERATNE

MANAGEMENT

Postoperative care is determined by the amount of tension on the nerve repair and the extent of joint flexion used to permit the repair. Early postoperative care should avoid placing tension on the repair site. If the nerve repair has been performed across a joint under any tension, the joint should be immobilized for 4 to 6 weeks to allow the nerve repair to regain adequate strength. Conflicting studies have been reported regarding bursting strength gain after nerve repair, ranging from 77% at 4 weeks to normal nerve strength within 3 to 4 weeks.18’ lg Even if the wrist is flexed to permit direct nerve repair, the distal joints should be manipulated passively without endangering the repair site to prevent joint stiffness and tendon adhesions. After primary nerve repair, an advancing Tinel’s sign should be elicited after adequate time has elapsed for the regenerating axons to bridge the repair site. This latent period is determined by the time required for the cell’s regenerative processes to become organized and for the regenerating fibers to traverse the repair site. Regenerating fibers advance at approximately 1.0 mm per day. If the repair has been perfect, the latent period will be short. A perfect repair, however, is never actually obtained. Delay beyond the latent period suggests that the adequacy of the repair is questionable. If the decision to explore and repeat the repair is delayed, fibrosis and shrinkage of the distal endoneural tubes become extensive enough within a few months to interfere with regeneration. The indications for delayed repair are (1) nerve division by a blunt 760

Cum

Pi-obl

Surg,

August

1963

instrument that inflicts considerably more tissue damage than is readily apparent, (2) avulsion injuries, and (3) grossly contaminated injuries. Delayed repair offers some advantages. The level of viable nerve is strikingly obvious, and fibrosis around the funiculi provides added purchase for nerve suture. It is helpful at the time of acute injury to overlap the nerve ends with a single suture if delayed repair is anticipated. This maneuver reduces the need for extensive mobilization of the nerve ends during subsequent delayed repair, thereby reducing tension at the repair, minimizing interference with blood supply, and permitting joint positioning to avoid stiffness. TENDON

INJURIES

The loss of tendon continuity can be the result of avulsion of the tendon from its insertion, disruption of the tendon substance, or laceration (Table 6). Avulsions are accompanied by a traumatic event. Examples of this type of injury include avulsions of the flexor digitorum profundus tendon from its insertion in the distal phalanx and of the extensor tendon insertions into the middle or distal phalanges. Roentgenograms may demonstrate a bone chip accompanying the avulsed tendon. Disruption of tendon substance is most often associated with a synovitis, such as rheumatoid arthritis, traumatic synovitis, or a nonspecific tenosynovitis. Disruption is characterized by a sudden, almost painless, loss of active flexion or extension in a digit associated with minor exertion, such as lifting a coffee cup. Tendon lacerations result from a traumatic event and must be associated with a skin laceration. TENDON

AVULSIONS

Evaluation

of FleFor

Tendon

Avulsions

The tendon is the strongest component of the bone-muscle-tendon unit in the upper extremity. When placed under stress, rupture rarely occurs in the substance of the tendon or muscle. Usually, the unit disrupts at the bony insertion of the tendon into the distal phalanx.’ Diagnosis of this type of injury is often missed because pain, swelling, and ecchymosis are minimal. Additionally, the radiographs may be unrevealing and the finger can still be actively flexed at the MP and PIP joints. A delay in diagnosis is associated with a poor prognosis. The injury is most frequent in young adults participating in sporting activities but may occur at any age. The ring finger is affected most often, but the injury has been reported in the thumb and all fingers. Classic examples of this type of injury include the patient injured by a sudden jerk on a rope, such as starting a lawn-mower engine or trying to restrain an animal. The tendon may retract into the Curr

Probl

Surg,

August

1993

761

carpi radialis;

Yes

Lacerations

Flexor

No

Disruption

FCR,

No

Wound

6. Interruution

Avulsion

TABLE

FPL, flexor

Trauma

pollicis

longus.

MY

All

wrist

Insertion,

all tendons

Extensors,

wrist

Palm,

Flexors profundus, flexors superlicialis, FCR, FPL

Minor

trauma

Distal phalanx Middle phalanx Distal

slip

Flexors profundus Extensors central Terminal extensor

Trauma

Event

Site

Continuity Tendons Involved

of Tendon

Synovitis, rheumatoid arthritis, old injury Synovltis, rheumatoid arthritis, old injury None

None None None

Associated Disease

Normal

Old injury process

or arthritic

Fracture possible Fracture possible No fracture Fracture, nondisplaced fragment No subluxation, distal phalanx Old injury or arthritic process

X-ray

(reattach) (reattach)

Primary (clean

repair wound)

Tendon graft or transfer

Tendon graft or transfer

Splint

Surgery Surgery Splint Splint

Treatment

palm and the patient eventually presents with a tender lump in the palm. Tenderness within the digital sheath is usually present from accumulation of blood. Factors influencing the prognosis in treatment of this injury include the level at which the tendon retracts, the remaining blood supply to the avulsed tendon, the length of time between injury and treatment, and the presence and size of a bony fragment on roentgenographic examination. Profundus avulsions from its insertion have been classified into three types.” In type I injuries, the tendon retracts into the palm and the vincula are ruptured (Fig. 16). In type II injuries, the tendon retracts to the level of the PIP joint and the long vinculum may be intact. A bony fragment may or may not accompany the tendon end, In type 111 injuries, a large bony fragment is present and the A-4 pulley prevents retraction of the bony fragment beyond the distal portion of the middle phalanx (Fig. 17). The long vinculum remains intact. Treatment should be early in all cases of tendon avulsion. Delay of treatment leads to a poorer result. In type I and type II injuries, the tendon end will enlarge to such a size that it is impossible to thread the tendon back through the digital sheath. In type III injuries, the tendon remains in the digital sheath and repair can be accomplished at a later date, although early repair still gives the best results. If reattachment of the tendon to its insertion is not possible, the choices of treatment include (1) fusion of the DIP joint, (2) resection

FIG. 16. The profundus tendon larged, preventing advancement the distal Dhalanx. Curr

Probl

Surg,

August

1993

has retracted of the tendon

into the palm (arrow), shortened, and through the digital sheath for attachment

ento

763

FIG. 17. The profundus (arrow).

tendon

has

been

avulsed

from

the distal

phalanx

with

a fragment

of bone

of the tendon and insertion of a flexor tendon graft, and (3) a twostage flexor tendon graft with a silicone elastomer rod followed by tendon grafting. The best results are obtained through early diagnosis and surgical advancement and reattachment of the avulsed tendon to the distal phalanx. Elrtensor Tendon Avulsions: Mallet Finger Avulsion of the extensor tendon at the distal phalanx produces a mallet deformity because the pull of the flexor digitorum profundus on the distal phalanx is unopposed. There may be a bony fragment accompanying the tendon, which will be evident on roentgenogram (Fig. 18). Treatment includes 6 weeks of immobilization in extension with an external splint. Extensor Tendon Am&ions: Middle Phalam The primary concern with extensor tendon avulsions of the middle phalanx is the lateral bands of the extensor apparatus. If their support (the triangular ligament) is disrupted, these structures can displace volarly, leading to the development of a boutonniere deformity. In suspected injuries of this type, the PIP joint is splinted in extension for 6 weeks. If a bony fragment is displaced with the extensor tendon insertion, open reduction and internal fixation are indicated (Fig. 19). 764

Cur-r Probl Surg,

August

1993

FIG. 18. Extensor ment don.

tendon function has site at the distal phalanx. A bony

TENDON

been precluded fragment (arrow)

by a fracture accompanies

involving its attachthe retracting ten-

DISRUPTIONS

Tendon disruptions usually occur when the patient is exerting minimal effort. There is virtually always an associated synovitis, usually rheumatoid arthritis; however, this type of injury may also occur poflicis after a Colles’ fracture, resulting in rupture of the extensor

FIG. 19. Fracture tendon

Curr

of the

dorsal

lip of the

middle

phalanx

(arrow)

precludes

extensor

function.

Probl

Surg,

August1993

765

longus tendon.‘l Most ruptures occur over bony prominences, such as the distal ulna and Lister’s tubercle at the distal radius. The most frequent tendons to rupture spontaneously are the extensor digiti minimi and common extensors to the ring and little fingers. The distal ulna is prominent and an associated synovitis leads to the disruption. Rupture of the extensor pollicis longus tendon at Lister’s tubercle may be caused by rheumatoid synovitis or an old fracture of the distal radius with resultant tenosynovitis. The tendon gradually thins at the point of irritation, eventually rupturing with minor trauma. Because the tendon ends are so attenuated, direct repair is impossible. Treatment choices include either tendon transfers or tendon grafts. TENDON LACERATIONS Evaluation The initial physical examination in patients with suspected tendon lacerations requires a series of simple clinical tests that are an exercise in applied anatomy. Never rely on someone else’s evaluation. The site and depth of skin injury provide clues as to which underlying structures may be injured. Simple observation of the upper extremity in repose can provide much information, particularly with regard to the flexor tendons. With the hand in repose, an extended finger indicates division of both tendons (Fig. 20). This is true for any level of laceration. Testing tendon function involves testing active joint motion. The profundus tendons are tested by having the patient actively flex the DIP joint of each finger. The thumb flexor is tested similarly. Superficialis continuity can be determined by holding adjacent fingers in extension and having the patient attempt finger flexion. If the PIP joint flexes, the superficialis tendon is intact. The extensor tendons are evaluated by having the patient fully extend the fingers and thumb. If there is a lag in extension and a skin wound is present over the tendon, one must inspect the wound, anticipating a tendon laceration. It is possible to extend a finger with a variable degree of extensor lag even if the long extensor tendon is cut. This extension is accomplished by the connections between the extensor tendons at the level of the MP joint. Primary Tendon Repair In clean wounds, all tendons should be repaired primarily. Particular attention must be directed to the digital sheath within the fingers and thumb. This digital sheath consists of annular and cruciate pulleys, which must be preserved (Fig. 4). The pulley system consists of annular and circular fascial thickening, reinforcing a synovial lined sheath that encircles the flexor tendons from the distal palmar crease 766

Curr

Probl

Surg,

August

1993

FIG. 20. With the hand gers

is suggested

in repose, division of the flexor by extension of these fingers.

tendons

to the

ring

and

little fin-

to the insertion of the profundus tendon into the distal phalanges of the fingers. In the thumb, the sheath extends from the level of the MP joint to the distal phalanx. This sheath functions to increase the mechanical advantage of the flexor tendons by maintaining the tendons in close proximity to the phalanges and joints. If the annular pulleys are cut, the tendons will bow across the joints, thereby limiting digital extension, producing a flexion deformity of the joints, and reducing grip and pinch strength. Preservation of the A-Z and A-4 pulleys is mandatory. These pulleys should never be sacrificed. The A-l, A-3, and A-5 pulleys can be sacrificed with little functional loss. The cruciate pulleys are extremely thin and may be sacrificed without functional loss. The narrow dorsal retinaculum covering the extensor tendons at the wrist should be preserved. Primary repair is contraindicated in a severely contaminated wound, when there is a loss of tendon substance of greater than 1.5 cm, or when there is a loss of the A-2 or A-4 pulley. If the wound is Cur-r Probl

Surg,

August

1993

767

contaminated, delayed primary repair is possible with good results. The skin wound is closed and observed while maintaining passive joint motion. Delayed repair is performed within 10 to 14 days if there is no evidence of infection. Delayed primary repair is precluded by enlargement of the proximal tendon end, which contracts into the palm and thus cannot be passed back through the narrow digital sheath; collapse or loss of the pulley system, particularly the A-Z or A-4 pulley; and the presence of extensive scarring within the tendon bed. If these conditions are encountered, one must consider a tendon graft. The contraindications to tendon graft are loss of the pulley system requiring pulley reconstruction, extensive scarring within the tendon bed, and the presence of stiff joints. If a flexor tendon graft is not possible for these reasons, then the stiff joints must be corrected and a silicone elastomer rod must be inserted to obtain a smooth bed for the new tendon graft, which will be inserted later.

Partial Laceration

of Flexor Tendons

Partial tendon lacerations of the flexor tendons or the extensor tendons proximal to the MP joint may not require repair.” Such injuries do, however, require careful management until the healing is complete. Partial lacerations of the extensor tendons at or distal to the MP joint level must be repaired. If the partial flexor tendon laceration is proximal to the A-l pulley with the finger fully extended, the following procedure is recommended. First, inspect the wound and enlarge the laceration if necessary. If the tendon is beveled, resect the beveled edge. The partially cut tendon should not be sutured. Use a dorsal splint to protect the tendon. Early guarded motion just to the point of discomfort is permitted, and exercises against resistance are begun 3 weeks after injury. Normal use of the hand is permitted 6 to 8 weeks after repair, depending on the patient’s occupation. If the level of partial flexor tendon laceration is within the digital sheath when the fingers are fully extended, the following procedure is recommended. If sensation and range of motion are normal in the finger, the wound edges are retracted and the digital sheath is inspected as the patient flexes and extends the fingers. If the digital sheath has been lacerated, the digit is anesthetized and the wound is enlarged for exposure. The tendons are observed as the patient fully extends and flexes the fingers. If there is obvious internal triggering, the sheath is repaired and the tendon is observed during flexion and extension. If triggering persists, the sheath is opened, the tendon is repaired, and the sheath is closed. If the tendon laceration is beveled, the beveled edges are resected. The digital sheath is repaired and early guarded motion is allowed to the point of discomfort. Exercises against resistance are begun early after injury and a dorsal

768

Curr

Probl

Sur.

August

1993

splint is used to protect the fingers. Normal use of the hand is permitted in 6 to 8 weeks, depending on the patient’s occupation. The complications from a partial tendon laceration may include rupture, either external or internal triggering of the finger, and entrapment. Rupture is best prevented by correctly making the diagnosis of a partial cut of the tendon and using protective motion after operation. The potential complication of internal triggering is prevented by repair of the sheath and early motion or repair of the tendon and resection of the C-l pulley. External triggering may be prevented by early motion and partial resection of the A-l pulley. Entrapment is prevented by resection of the beveled edge of the tendon and repair of the sheath. Complete Tendon Lacerations The restoration of tendon function after complete tendon laceration requires maintenance of tendon gliding and supple joints, not simply tendon repair. Surgical efforts are directed toward obtaining healing in a milieu that will produce favorable scar tissue that will undergo biologic alteration to form adhesions that can be favorably modified by stress to permit tendon gliding. Ideally, a tendon repair is accomplished in a bed of loose, areolar tissue. However,. the tendons are contained within a specialized fibroosseous sheath within the fingers and thumb. This sheath is composed of dense fibrous tissue, which encircles the repair and can result in dense nonyielding scar that prevents tendon gliding. Previously, it was thought that tendon lacerations within the digit should not be repaired but should undergo tendon grafting at a later date. This concept has been completely refuted, and primary tendon repair is now recommended whenever possible even within the digital sheaths. The advantages of primary tendon repair include (1) pulley and sheath preservation, (2) minimal dissection, (3) predetermination of muscle tension, (4) single repair site, (5) early motion, encouraging the patient and reducing stiff joints and adhesions about the tendons, (6) minimal lost time from work, and (7) potential requirement of a limited tenolysis. To minimize the scarring about the tendon repair, special surgical techniques and postoperative rehabilitative techniques have been developed. These include minimal exposure of the digital sheath, repair of the tendons with specialized tendon sutures to yield maximum tendon strength, especially during the early postoperative period, repair of the lacerated sheath, and early passive motion of the repaired tendon after operation. All pulleys should be preserved, particularly the A-Z and A-4 pulleys. When the A-2 or A-4 pulley is injured, it can be reconstructed in a variety of ways with tendon grafts. Many surgeons prefer repairing the pulley over a silicone elastomer rod and subsequently removing the rod and inserting a flexor Cum

Probl

h-g,

August

1993

769

tendon graft. Sacrifice of either the A-2 or A-4 pulley results in “bowstringing” of the flexor tendon across the PIP and a permanent flexion contracture of the joint, which is extremely difficult to correct. Extensor tendon lacerations are treated by primary repair. A narrow retinaculum over the dorsum of the wrist forms a pulley system for these tendons. Some surgeons have recommended mobilization of extensor tendon repairs immediately with either active or passive motion, but most surgeons wait 3 to 4 weeks before beginning active motion and report excellent results. Suture

Techniques

Many suture techniques have been recommended for tendon repair. Currently, the techniques are directed toward minimizing interference with blood supply within the healing tendon and providing enough tensile strength in the early postoperative period to allow active mobilization of the tendon and joints. This minimizes adhesions about the tendon repair, maximizes tendon gliding, and prevents the development of stiff joints. A technique of tendon repair with a double-loop locking suture (“Dolls”) has been deveiopedt3 in which the longitudinal load placed on the tendons is transferred into a transverse compressive force (Fig. 21). The preferred suture material is nonabsorbable, multiple-filament 4.0 nylon suture. The tensile strength of the repair in healing tendons is similar to that of the suture material. Postoperative

Management

When operative repair of the tendons has been completed, a plaster splint is applied from the dorsum of the forearm to the fingertips. The wrist is held in 30 degrees of flexion, the MP joints are held in 60 degrees of flexion, and the PIP and DIP joints are permitted full extension. Active extension and passive flexion are begun within 24 hours, with gentle active extension and passive flexion performed 10 times per hour and added passive flexion for stiff fingers. Between the sessions of hourly exercise and while the patient is asleep, the interphalangeal joints of the fingers and the thumb are maintained in extension by rubber-band traction or by use of a fabric touch fastener strap around the fingertips for the first 2 weeks after operation. After 2 weeks, the plaster splint is removed and an orthoplastic splint is applied. Care is taken to prevent excessively aggressive active motion of the tendons. After repair of extensor tendons lacerated at or proximal to the MP joints of the fingers or thumb, a volar splint is applied. The splint allows 30 degrees of motion at the MP joints. Gentle active flexion and extension are begun within 24 hours. Splinting is used for 5 weeks in the fingers and 6 weeks in the thumb. The results from use 770

Curr

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1393

FIG. 21. Placement of the Dolls suture is demonstrated from the lower left hand corner to the upper right hand corner. (From Lee H. Double loop locking suture: a technique of tendon repair for early active mobilization. J Hand Surg [Am] 1990;15:945-52 [with permission].)

of these techniques are excellent for both flexor and extensor tendon repairs. An algorithm for management options when a good result is not obtained is presented in Fig. 22. If adequate function is not regained after tendon repair, the cause may be adhesions about the tendon repair, stiff joints caused either by injury or by immobilization, or rupture at the repair site. The algorithm shows the options for managing each of these conditions. For example, if tendon function is inadequate, there are no significant tendon adhesions, and the joints are not stiff, then the repair site is ruptured. Furthermore, if adhesion formation is so severe that simple tenolysis is not possible, a staged tendon reconstruction should be considered. This requires excision of the scarred tendon, insertion of a silicone elastomer rod, and subsequent (6 to 10 weeks) removal of the rod and insertion of a flexor tendon graft. BONE INJURIES In treating any hand injury, and particularly fractures, it is important to be aware of edema formation. Edema is a reflection of the Curr

ProblSurg,

August

1993

771

FIG. 22. Management

algorithm when a good result is not obtained after initial tendon repair. (From Weeks PM. In: Georgiade N, et al., eds. Essentials of plastic, maxillofacial, and reconstructive surgery. Copyright 1987, the Williams & Wilkins Co., Baltimore.)

forces that produced the injury and a manifestation of tissue damage that results in an alteration of capillary permeability. The proteinrich edema fluid attracts water into the interstitial spaces until normal capillary permeability is reestablished. This edema fluid surrounds the collateral ligaments of the joints and tendons. As new collagen is produced, these structures are encased in nonyielding scar tissue. Edema is most evident over the dorsum of the hand because of the laxity of the tissues. The metacarpal phalangeal joints are forced into hyperextension and the PIP joints are forced into flexion. The collateral ligaments of the metacarpal phalangeal joints are lax 772

Curr

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1993

when the joints are extended and may become fixed in this shortened position. Optimum fracture treatment includes reduction and immobilization of the fracture, maintenance of digital length and proper rotation, preservation of joint motion, minimization of edema formation, and maintenance of tendon gliding and joint mobility. In children, fractures frequently involve the epiphyses and require particular attention.

EPIPHYSEAL

FRACTURES

Epiphyseal injuries may not involve the joint surfaces and are therefore discussed separately in this section. Because the epiphyseal plate is weaker than bone, ligament, or tendon, traumatic separations of the epiphyseal plate are frequently seen in children, whereas tendon and ligament injuries are infrequent. The epiphyseal plate can be divided into four distinct zones of cells: the resting cell zone, the proliferating cell zone, the hypertrophying cell zone, and the endochondral ossification zone. The vascular supply of the epiphyseal plate is derived from vessels on both the epiphyseal and metaphyseal sites, which are located in the layer of endochondral ossification. When an epiphysis is completely covered with cartilage, its blood vessels penetrate the rim of the epiphyseal plate, where they are vulnerable to injury. Frequently, epiphyseal fractures involve the phalanges, especially the base of the proximal phalanx. The fracture typically results from a twisting injury that rotates and angulates the distal fragment. These fractures are difficult to reduce because the small proximal fragment cannot be grasped. Closed reduction should be attempted, but often the displacement cannot be fully corrected, resulting in some persistent angulation. Open reduction is avoided if at all, possible. The involved finger is strapped to the adjoining finger and both are splinted in a position of slight flexion for a period of 4 weeks. Any persistent angulation usually subsides with active use, and normal excursion of the fingers in flexion and extension is restored. Growth disturbances can occur because of fractures of the epiphyses. Classification

of Injuries

to the Epiphyseal

Plate

Injuries to the epiphyseal plate have been classified into five types .24 In type I fractures, separation of the epiphysis occurs through the hypertrophying layer of cartilage cells. Because the proliferating cells are intact, the epiphysis will survive unless the nutrient vessels are disrupted. If the vascular system remains intact, healing is rapid and complete within 3 weeks and the prognosis is good. An example of type I epiphyseal fracture is separation of the epiphysis of the distal phalanx (Fig. 23, A). The phalanx is usually flexed and displaced Cur-r Probl

Surg,

August

1993

773

FIG. 23. A, Type

I fracture (arrow) has occurred transversely through the hypertrophic layer of cartilage cells. Because the proliferating cells are intact, the epiphysis will survive. B, In a type II fracture, the epiphysis is disrupted together with a triangular segment of the metaphysis (arrows). (Continued.)

laterally and the epiphysis remains extended relative to the phalanx. Closed reduction by traction and application of lateral and vertical pressure on the joint and phalanx correct lateral and volar displacement. The finger is immobilized with an external splint or a smooth Kirschner wire threaded through the distal phalanx, its epiphysis, 774

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1993

FIG. 23 (cont.).

C, In a type III fracture, the fracture line (arrow) extends from the articular surface of the epiphyses to the hypertrophic layer of cartilage cells of the plate and then laterally through this zone to the periphery. D, The type IV fracture (arrow) extends from the articular surface through the epiphyses across the epiphyseal plate and through the metaphyses at the same level. (Continued.)

FIG. 23 (cont.). E, In a type V fracture, a portion compression (arrow). This may lead to premature distorted growth.

of the epiphyseal plate closure of the epiphyses,

is crushed resulting

by in

and the DIP joint. After 3 weeks, the pin is removed and motion exercises are begun. Occasionally, the fibers of the extensor tendon become interposed in the fracture line, necessitating open reduction. In type II fractures, the epiphysis is separated with a triangular segment of the metaphysis (Fig. 23, B). The periosteum is preserved on one side and helps to stabilize the epiphysis after reduction. Generally, the blood supply to the epiphysis is not damaged, so the prognosis is good. The small triangular portion of the metaphysis is displaced with the epiphysis, allowing the proximal phalanx to rotate on the epiphysis. Closed reduction can be accomplished readily. While steady traction is applied to the finger, the finger is rotated in the opposite direction of the deformity. A roentgenogram confirms 776

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1993

reduction. The finger is immobilized by a posterior plaster shell extending from the mid forearm to the tip of the finger, with the MP and interphalangeal joints in slight flexion. The plaster is removed after 3 weeks and motion exercises are begun. In type III fractures, the fracture line extends from the articular surface of the epiphysis to the hypertrophying layer of cartilage cells of the plate, then laterally through this zone to the periphery (Fig. 23, C). As in other joint injuries, it is essential to restore the congruity of the articular fragments. The prognosis is good because the vascular supply is intact. In type IV fractures, the fracture line extends vertically across the full thickness of the epiphysis, the epiphyseal plate, and a triangular wedge of metaphysis (Fig. 23, Dl. The incongruity of the articular surface should be noted. Complete anatomic reduction in this lesion is essential to realign the plate and restore a smooth articular surface. Some form of internal fixation may be necessary to maintain reduction. The extent of epiphyseal plate damage is unknown-and may be severe-so the prognosis is guarded. In type V fractures, a portion of the epiphyseal plate is crushed by compression (Fig. 23, E). This injury is most often encountered in joints moving in only one plane. Displacement of the epiphysis is unusual. Roentgenograms usually give no indication of the extent of injury. Premature closure of the plate with loss of growth and angular deformity is the rule. The prognosis is poor and surgical realignment may be necessary later in childhood. Factors Governing Prognosis of Injuries to the Epiphyseal Plates Type I, II, and III fractures have a good prognosis if the blood supply to the epiphysis is not disrupted. In type III fractures, anatomic realignment of the plate must be achieved. Type IV fractures are accompanied by a less favorable prognosis, but .the sequelae can be minimized by restoring alignment of the plate. Crushing injuries of the epiphyseal plate, as seen in type V fractures, carry a poor prognosis. Forceful manipulation during closed reduction or instrumentation during open reduction may further traumatize the epiphyseal plate and adversely influence the final result. Parents should be informed of the possibility of growth disturbances, which may not be apparent for many months. If the epiphyseal plate is not severely disrupted and its alignment is intact, as in type I and type 11 fractures, considerable displacement of the epiphysis can be tolerated. Remodeling will restore the anatomic position of the epiphysis. If the plate is misaligned and articular incongruity present, as in type III and type IV fractures, it is essential that anatomic alignment be restored even if open reduction is required.

Curr

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Surg,

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1993

777

FRACTURES NOT INVOLVING (DIAZ’WSEAL FRACTURES) Optimal

ARTICULAR

SURFACES

treatment

of diaphyseal fractures includes (1) reduction of the fracture, (2) maintenance of digital length and proper rotation, (3) preservation of joint motion, (4) minimization of adhesion formation to gliding tendons, and (5) minimization of edema formation. Closed reduction can be accomplished, but open reduction is occasionally required. Immobilization can be accomplished with either external or internal splinting. External splinting with a plaster cast requires immobilization of at least the two joints in juxtaposition to the fracture. If external splinting is prolonged, stiff joints and tendon adhesions may develop. Dissatisfaction with external splinting has led to a greater interest in internal fixation and to the development of a “minifragment” set of plates and screws. The advantages of internal fixation include firm approximation and immobilization of the fracture, prevention of rotatory movement, maintenance of digital length, and minimal immobilization of juxtaposed joints. The disadvantages include infection, tissue injury from surgery, impingement of wires, screws, and plates on tendinous structures, and the reparative process evoked by surgery.

and immobilization

Metacarpal Fractures: Distal Transverse Fractures Distal transverse metacarpal fractures completely free the metacarpal head from any proximal stabilizing influence. The only attachments to the metacarpal head, the collateral ligaments, remain attached to the proximal phalanx. If the metacarpal head tilts volarly and the proximal phalanx is in a neutral position, the joint is actually hyperextended and the collateral ligaments become slack. If this is not corrected, the resultant scar will fix the collateral ligaments in a shortened position, blocking flexion. Inadequate reduction leaves a prominent metacarpal head in the palm, which may produce discomfort on grasping objects. This fracture can be reduced by gaining control of the metacarpal head through the collateral ligaments. The proximal phalanx is grasped and the MP joint is flexed 90 degrees to produce tightening of the collateral ligaments about the metacarpal head. While maintaining this control, pressure is directed dorsally onto the metacarpal head as the metacarpal shaft proximal to the fracture is forced volarly. After the fracture is reduced, the proximal phalanx is maintained in 70 to 80 degrees of flexion during a 3-week period of immobilization. Malrotation can be prevented by including the adjacent fingers in the splint. After 3 weeks, gentle exercises are begun. Fracture of Metacarpal Shajl The following metacarpal fractures are more likely to be unstable and to require open reduction and internal fixation: (1) spiral frac778

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Sur5

August

1993

tures, (2) oblique fractures involving more than one metacarpal shaft, (3) fractures through either the second or fifth metacarpal, (4) comminuted fractures, and (5) fractures in which segments of the bone are lost. When there is comminution of the fracture at the condylar neck, external fixation is difficult to maintain. Digital length can be maintained by a transverse Kirschner wire impaling the metacarpal head and penetrating the adjacent stable metacarpal. A single wire, however, does not prevent rotation of the metacarpal head on the wire. A second wire is required to provide complete immobilization. Exposure of the metacarpal may be necessary for accurate placement of these wires. Internal fixation is particularly helpful in the patient in whom the risk of stiff joints is high. Motion is begun within 24 hours. Metacarpal shaft fractures may be transverse, oblique, or comminuted. The transverse fracture angulates dorsally, producing volar displacement of the metacarpal head. Dorsal angulation results from the pull of the intrinsic and long flexor muscles, which are volar to the fracture plane. These fractures are frequently unstable in the index and little fingers. However, transverse fractures of the long and ring metacarpals are usually stable after reduction. Oblique fractures have a tendency to telescope because of the proximal pull of the intrinsic muscles. Rotational deformity of the fingers is therefore common in oblique fractures. The effect of slight malrotation at the metacarpal shaft on the distal phalanx is deceptively great. If 5 degrees of malrotation is accepted at the shaft of the metacarpal, then the distal phalanx will override 10.5 mm (Fig. 24). The importance of preventing malrotation cannot be overemphasized. Malrotation is minimized by passive flexion of all fingers into the palm while stabilizing the fractures and testing again after internal fixation. When there is a tendency toward shortening, length may be maintained by gentle closed reduction of the fracture and cross-pinning to an adjacent metacarpal. Skeletal traction to prevent shortening of the metacarpal is used infrequently because the pin for traction must be in the proximal phalanx and positioning the MP joint in extension for adequate traction predisposes toward the development of a stiff MP joint, Pulp or skin traction is difficult to maintain and can lead to circulatory embarrassment of the skin or digit. Fractures in the midshaft or neck of the metacarpal usually result in volar angulation of the distal fragment, displacing the metacarpal head into the palm. The metacarpal shaft fracture is reduced by flexing the MP joint to gain control of the distal fragment of metacarpal and forcing the metacarpal head dorsally while pushing the proximal metacarpal fragment volarly. If reduction is unstable because telescoping or shortening cannot be corrected and maintained, then internal fixation with a Kirschner wire driven transversely through the fractured metacarpal head and into the stable adjacent metacarpal is indicated. Application of plates requires more extensive disCur-r Probl

Surg,

August

1993

779

FIG.

24. A rotational deformity at the metacarpal 10.5 mm deviation at the tip of the finger.

shaft

level

of 5 degrees

will produce

a

section but may be necessary if reduction is not obtained. A second wire is needed to ensure stability. Cornminuted fractures usually result from low-velocity weapon injuries and require internal fixation to maintain length and proper rotation. The degree of shortening is eventually checked by the intermetacarpal ligament that attaches to the metacarpals. Fractures of the metacarpals of the index and little fingers are more difficult to treat than fractures of the long and ring metacarpals because the latter are splinted by intact metacarpals on either side. Fractures of the shaft of the long and ring fingers, which are stable after reduction, can be protected by a dorsal splint, thereby permitting active motion of the fingers. When a fracture is reduced and immobilized, pain around the site subsides rapidly. If pain persists, further investigation of the cause is mandatory. Disastrous results have been associated with fracture management when unexplained pain persists in a well-reduced, well-immobilized fracture. 780

Cur-r

Probl

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1993

Open reduction and internal fixation of metacarpal fractures is necessary in the following circumstances: (1) when a displaced fracture involves a joint, (2) when the fracture is markedly displaced so that the interposition of soft tissue prevents reduction, (3) when the fracture is unstable in a reduced position, and (4) when multiple fractures are present. The principles of treatment presented previously are applicable to fractures of the thumb metacarpal; however, the thumb is so important in hand function that particular care must be exercised to ensure proper reduction, alignment, and immobilization. The plane of metacarpal rotation across the palm must be fully appreciated when positioning the thumb after fracture reduction. Fractures through the base or shaft are displaced by the tendinous structures inserting into each fragment. The distal metacarpal fragment is flexed into the palm by the pull of the thenar muscles, as described earlier. The proximal fragment serves as an insertion for the abductor pollicis longus and produces extension-abduction of this fragment. Because extension of the proximal fragment is limited by the ulnar ligament, the distal fragment should be manipulated to effect and maintain reduction. Oblique and cornminuted fractures predispose to shortening and malrotation (Fig. 2.5). If the reduction is unstable, internal fixat,ion with Kirschner wires or plates and screws is indicated (Fig. 26). Proximal and Middle PhalangeaI Fractures Transverse fractures of the phalanges, particularly those involving the midshaft, heal slowly. The surface area of the midshaft is small and composed primarily of cortical bone. From 5 to 6 weeks of immobilization may be needed before adequate fixation occurs. The time of immobilization is determined by the type of fracture (transverse, oblique, cornminuted), the adequacy of reduction, the method of fixation (internal or external), and clinical assessment of the healing process. Roentgenograms are helpful in confirming fracture reduction, but the decision to begin mobilization is made through clinical assessment. Fractures of the proximal and middle phalanges are generally unstable. These phalanges are supported by the snug skin capsule and are subjected to the pull of tendons and tendinous aponeurosis transversing or inserting into the phalanges. Fractures of the proximal phalanx are usually held in a displaced position by the pull of the extensor mechanism and the interossei (Fig. 27). The interossei tend to flex the MP joint, pulling the proximal fragment of the proximal phalanx into flexion. Displacement of the flexor tendons within the fibroosseous tunnel into flexion pulls the distal fragment of the proximal phalanx volarly. The extensor mechanism accentuates this volar displacement and flexion of the PIP joint occurs. The fractures may be transverse, oblique, or cornminuted and the principles of fracCur-r Probl

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August

1993

781

FIG. 25. Oblique scope

proximally

fractures of the long, and rotate.

ring,

and little finger

metacarpals

(arrows)

that tele-

ture treatment discussed previously are applicable. Two additional considerations must be appreciated. First, the periosteum of the proximal and middle phalanges forms the dorsal wall of the fibroosseous tunnel in which the flexor tendons glide. Consequently, any fracture of these phalanges interrupts the continuity of the gliding surfaces of the flexor tendon sheath. Furthermore, impingement of the fracture site on the flexor tendons can produce direct damage to the tendons. If the digit is immobilized for an extended period, the flexor tendons can become adherent to the fracture site. It is therefore preferable to maintain tendon gliding while the fracture heals, To accomplish these goals, open reduction and internal fixation is frequently required. Placement of Kirschner wires in the proximal 782

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1993

FIG. 26. Open

reduction

and

internal

fixation

with

plates

and

screws

restore

anatomic

alignment.

phalanx is facilitated by acutely flexing the MP joint so that the base of the proximal phalanx is palpable. With a high-speed drill, the wire pierces the skin and penetrates the base of the proximal phalanx to exit on the opposite side of the phalanx. Plates and screws may be used effectively, but their placement requires extensive exposure, including splitting the extensor tendon. A second consideration is the need for early joint motion. Consider, for example, a compound crushing fracture of the proximal phalanx with dislocation of the DIP joint that is reduced and pinned directly. Three days after operation, active PIP and MP joint flexion is maintained. Less appropriate treatment may result in an unstable proximal fragment, adhesion of the flexor tendons to the site of fracture Cum

Probl

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August

1993

783

FIG. 27. A, An oblique fracture (arrow) of the proximal phalanx results in displacement of the distal fragment because of the pull of the flexor, extensor, and intrinsic musculature. B, If unreduced, this will heal in a shortened position. C, To prevent shortening, the fragments have been stabilized with two Kirschner wires.

callus, and checkreining of the proximal interphalangeal and MP joints. Any method that advocates immobilization of the PIP joint in acute flexion or of the MP joint in extension must be suspect. Distal Phalaw Fractures of the distal phalanx usually result from crushing injuries that produce significant soft-tissue injury. In such cases, the primary concern is soft-tissue repair. When the fractures are comminuted, the fragments are molded into position and splinted. These fractures frequently fail to unite. Chip fractures involving the base of the distal phalanx must be evaluated for avulsion of the insertion of the extensor tendon or the flexor tendon. There is a direct relationship between the period of immobilization and the final result. Poor results are obtained in finger fractures immobilized for more than 3 weeks. If finger fractures are immobilized for 4 weeks, 60% of patients have significant joint stiffness and loss of hand function. JOINT

INJURIES

ARTICULAR FRACTURES OF THE ADULT SKELETON Articular fractures may be associated with dislocations of the injured bone. Fractures extending into an articular surface present problems not encountered in diaphyseal fractures. These problems 784

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1993

are created by (1) the reactions evoked in healing of fractures extending through articular cartilages, (2) the need to maintain a smooth gliding surface for proper joint function, and (3) edema formation after injury. Disruption of the smooth cartilaginous articular surfaces can lead to the development of traumatic arthritis. Recognition of the hazards of edema formation is essential. If the collateral ligaments and soft tissues surrounding the joints are allowed to participate in the healing phenomenon in a shortened position, the joints will become stiff. Similarly, edema around tendons is associated with collagen deposition that restricts the tendon gliding. Thumb: Carpometacarpal Joint Because the thumb plays such a major role in hand function, any injury involving the thumb is of major importance. The base of the thumb metacarpal articulates with the saddle-shaped trapezium. The metacarpal base presents the reciprocal of the saddle joint to aid in stability. The radial lateral ligament, which is covered by the abductor pollicis longus tendon, inserts into the thumb metacarpal. The volar edge of the metacarpal base (volar beak) receives the insertion of the ulnar (anterior oblique) ligament. This ligament inserts proximally into the ridge of the tubercle on the trapezium. The dorsal capsular ligamentous structures are covered by the extensor pollicis brevis and longus tendons. The entire capsule is redundant. The ulnar ligament limits the range of abduction and extension of the thumb. If this ligament is not functioning, the unopposed pull of the abductor pollicis longus and extensor pollicis longus and brevis muscles dislocates the metacarpal shaft radially and proximally (Fig. 28). Fracture dislocations involving this joint require accurate reduction and maintenance of this reduction to minimize traumatic arthritis, persistent pain, and instability. Two opposing treatment views have developed. One view supports closed reduction and simple plaster immobilization even though the late anatomic results, as judged radiographically, are poor.25 The functional results are often excellent despite poor reduction. The opposing view notes that closed reduction of the fracture dislocation may be accomplished readily, but maintaining reduction with plaster casts is difficult. Traction is introduced to counteract the unopposed pull of the abductor pollicis longus and the short and long extensors. Skin traction often proves inadequate and even dangerous. Skeletal traction is therefore more satisfactory. Over time, authorities began to recommend placement of the pins for traction closer to the fracture site and internal fixation of the displaced fracture has gradually become the nonnz6 Advocates of internal fixation to maintain reduction have suggested the following techniques: (1) percutaneous pinning across the reduced fracture site, (2) percutaneous pinning of the thumb metacarCur-r Probl

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August

1993

785

FIG. 28. The volar

beak of the thumb positioned by the intact anterior oblique arrows) is displaced dorsally by extensor

metacarpal (single arrow) remains reduced ligament while the shaft of the metacarpal and abductor muscle pull.

and (two

pal to the index metacarpal after the fracture has been reduced, (3) percutaneous pinning across the fracture site and into the trapezium, and (4) open reduction and direct fixation with pins or screws (Fig. 29). The results are excellent. Closed Reduction and Plaster Immobilization.-Closed reduction can usually be accomplished without difficulty. Maintaining this reduction requires constant pressure on the base of the metacarpal fracture until union has occurred, usually about 6 to 8 weeks. Frequently, a palpable click can be detected as the bone is reduced. This requires a snugly fitting cast, which must be adequately padded to prevent skin necrosis at the points of pressure. Adhesive felt is utilized to pad the pressure points. Plaster is applied one strip at a time to allow molding to the contour of the hand, wrist, and forearm. While the plaster is still soft, traction is applied to the thumb and the fracture is reduced by direct pressure over the base of the thumb metacarpal. This position is maintained until the plaster has hardened enough to permit further reinforcement with plaster. Radiographs are taken at 1 and 2 weeks to confirm reduction. At 6 weeks, the plaster is discarded and gradual motion is begun. Skeletal traction is the safest and most efficient method for apply786

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1993

FIG. 29. Under nal fixation has

direct visualization, been accomplished.

the fracture

from

Fig. 28 has

been

reduced

and

inter-

ing traction. A Kirschner wire is inserted across the metacarpal shaft near the condylar neck and an outrigger is incorporated into the thumb spica cast. The cast is carefully molded around the base of the thumb, the palmar aspect of the head of the metacarpal, and the radial side of the thenar eminence. Open Reduction and Internal Fixation.-A the base of the thenar eminence is curved Cur-r

Probl

SW..

August

1993

transverse incision at distally along the radial 787

dorsal surface of the metacarpal. The skin flap is reflected and the thenar muscles are reflected from the metacarpal. This exposes the carpometacarpal joint. The joint capsule is entered laterally, preserving the dorsal and volar ligamentous attachments. The bony fragment is then identified. The fracture is reduced, aided by traction on the thumb and pressure on the dorsum of the metacarpal, and a Kirschner wire is driven across the base of the thumb metacarpal into the volar fragment. Care must be taken to ensure accurate anatomic reduction of the fragments. The wire is cut, the thenar muscles are reattached, and the skin edges are sutured. Plaster cast immobilization is used for 6 to 8 weeks. This method has subsequently been adopted by many of the earlier advocates of closed reduction and plaster cast immobilizationz7 A lag screw can be inserted through the metacarpal base and into the fragment. Fingers MP Joint.Fractures of the MP joint may involve the proximal phalanx, metacarpal head, or both. Fracture of the proximal phalanx occurs from direct force on the head of the proximal phalanx with the MP joint in extension. The base of the phalanx fractures with significant separation of the fragments. Internal fixation is recommended to reconstruct the smooth articular surface and to allow early motion. Closed reduction of the fracture and percutaneous pinning of the fragments is usually adequate, but open reduction may be required. Interposition of soft tissues in the fracture site requires open reduction. Fracture of the articular head of the metacarpal is an infrequent variant of the “boxer’s fracture.” In this injury, the impact is received directly on the metacarpal head, producing a fracture through the joint surface (Fig. 30). Telescoping of the fragment IS frequent. This fracture must be treated aggressively. If closed reduction cannot be obtained (and it usually cannot), open reduction is required. The fragment is fixed with either Kirschner wires or screws after anatomic reduction. Early mobilization must be instituted to prevent the development of stiff joints. PIP&i&.-Injuries to the PIP joint may result in the greatest functional loss of any single fracture in the hand. Fracture dislocation at the PIP level usually presents as a fracture of the ventral rim of the base of the middle phalanx (Fig. 31). The fracture may involve more than 50% of the articular surface; however, it is usually 20% to 40%. Because the volar plate of this joint is attached to this fragment, the accessory collateral ligaments, volar plate, and bony fragment maintain their normal relationships. Dislocation occurs because the joint surfaces have lost their structural congruity and the central slip of the extensor apparatus pulls the middle phalanx dorsally and prox788

Curr

Probl

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FIG. 30. A direct row),

necessitating

injury open

to the metacarpal head has resulted reduction and internal fixation.

in an articular

fracture

(ar-

imally. The larger the volar fragment, the greater the chance of dislocation. The proper collateral ligaments may remain attached to the middle phalanx and become slack as the middle phalanx is displaced dorsally. In some cases, at least one of the collateral ligaments is torn. The subluxation may be easily reduced; however, maintaining reduction is most difficult. If not treated aggressively, traumatic arthritis develops in the joint, which remains swollen, tender, unstable, and sensitive to minor trauma. A variety of methods of management have been suggested, ranging from closed reduction, to closed reduction and skeletal traction, to open reduction and internal fixation. The last method of treatment has become most popular and will be described. Treatment by acutely flexing the PIP joint and maintaining this position is mentioned only to condemn it. When a single, large volar fragment is present, open reduction and internal fixation yield a good result. The interphalangeal joint is exposed through a volar zigzag incision. The filmy portion of the fibrous digital sheath over the joint is opened to permit retraction of the flexor tendons and exposure of the volar plate. The volar plate is reCur-r Probl

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789

FIG. 31. Fracture the middle

phalanx,

of the volar lip of the middle which subluxes dorsally.

phalanx

(arrow)

can

result

in instability

of

fleeted proximally with the attached fracture fragment (Fig. 32). If the articular surfaces are cornminuted, one collateral ligament is detached, the joint is hinged open, and the surfaces are inspected and reduced. If the fracture is not cornminuted, the collateral ligaments are left intact. The displaced middle phalanx is reduced and a fine Kirschner wire is drilled through the bony fragment and into the middle phalanx. A second Kirschner wire is placed obliquely across the joint to prevent recurrent dislocation during fracture healing. If the collateral ligament was detached, it is repaired. If the fragment is too small to receive a Kirschner wire or is cornminuted, it is excised and the volar plate is sutured directly to the defect in the middle phalanx. When the volar lip is severely cornminuted, an alternative is to position a pull-out wire through the volar plate just proximal to its insertion into the volar lip fragments. This wire encircles the bone and is tied over a button on the dorsum of the middle phalanx. The transarticular wire is removed after 5 to 6 weeks. Excellent results with this technique have been reported in a large series.z8 DIP Joint.-Fractures involving the DIP joint usually result from crush injuries and may be compound. These fractures require splinting for 4 to 6 weeks, followed by gradual mobilization. Occasionally, longitudinal fractures of the middle phalanx extend between the condylar heads. These fragments should be reduced and fixed with one 790

Curt- Pmbl

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1993

FIG. 32. A, The flexor

sheath has been opened over the PIP joint and the flexor tendons have been retracted, exposing the detached volar plate (arrow). 6, With the flexor tendons retracted, the volar plate is elevated, exposing the PIP joint and the site of bony fracture (volar lip middle phalanx) (arrow).

or more transverse Kirschner wires. This allows early movement and minimizes adhesion formation between the healing bony fragments and the adjacent extensor and flexor tendons. If fixation and early mobilization are not instituted, significant adhesion formation may result. DISLOCATIONS

The dislocated joint must be thoroughly examined to rule out fracture, ligament rupture, and partial ligament rupture, in that order. Sprain, a partial tear of a ligament or capsule, is a diagnosis by exCurrProblSurg,

August1993

791

elusion. Stress roentgenograms must be obtained to determine ligament rupture. These roentgenograms cannot be interpreted as normal until the injured part has been anesthetized. Often the ligament avulses a fragment of bone at its attachment, rather than rupturing through its substance, and this displaced fragment can be detected on roentgenogram. For a complete dislocation to occur, joint ligaments must be disrupted. It is our purpose here to review joint dislocations, to discuss the anatomic derangements associated with the injuries, and to present the current methods for management.

Thumb Carpometacarpal Joint.-The base of the thumb metacarpal articulates with the saddle-shaped trapezium. It is maintained in this saddle by the ulnar ligament, which originates on the volar beak of the thumb metacarpal and inserts on the tuberosity of the trapezium. A thinner dorsal ligament is reinforced by the broad insertion of the abductor pollicis longus into the base of the metacarpal. A second slip of abductor tendon is frequently present, overlying the joint anteriorly. Dislocation is almost always dorsal (Fig. 33). Even though anatomic reduction is readily accomplished and maintained by proper casting, subsequent instability in the joint is frequent. Little?’ suggests open reduction and reconstruction of the disrupted ligament (Fig. 34). With this technique, there is an excellent prognosis for a stable thumb. MP Joint: Dorsal Dislocations.Hyperextension injury of the MP joint is the penultimate event before dorsal dislocation. The hyperextension injury ruptures the volar plate attachments, the accessory collateral ligaments, and at least the volar part of the proper collateral ligaments. Physical examination can reveal much concerning the degree of injury, particularly if the joint has been reduced before examination. Swelling, point tenderness, and function are assessed. Unopposed passive hyperextension of the joint not present before injury is indicative of interruption of the adductor pollicis or flexor pollicis brevis muscles. Palpation of the flexor pollicis brevis during thumb-to-index pinch can reveal the functional state of this muscle. If the muscle functions normally, then regional anesthesia is necessary to determine the extent of capsular damage. Complete dislocation indicates injury of the proper collateral ligaments. Asymmetric injury of the proper collateral ligaments produces rotation of the proximal phalanx as it is dislocated. If the volar plate is avulsed proximal to the insertions of the adductor pollicis and flexor pollicis brevis muscles, the sesamoids are noted on roentgenogram to follow the proximal phalanx into extension. If a fracture through the sesamoids is demonstrated on roentgenogram, the sesamoids are sewn together 792

Curr

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1993

FIG. 33. The thumb

is dislocated oblique ligament. (From Weeks yan S. Plastic surgery: principles

dorsally and laterally, completely disrupting the anterior PM, Pin PG. In: Jurkiewicz MJ, Krizek TJ, Mathes SJ, Ariand practice. St. Louis: Mosby, 1990:708.)

with sutures through the volar plate proximal and distal to the fracture. If the volar plate tear passes distal to the sesamoids, the sesamoids do not follow the displacement of the proximal phalanx. The most common site of volar plate rupture is proximal to the sesamoids. As a result, the tendons of the flexor pollicis brevis and the oblique head of the adductor pollicis straddle the metacarpal head. The flexor pollicis longus tendon is displaced laterally. Reduction is facilitated if the insertions of the intrinsic muscles to the sesamoids are intact (the muscles guide the volar plate back into proper positioning). If the metacarpal is flexed into the palm, the tension on the intrinsic muscles is lessened, thereby permitting gradual traction and flexion to complete reduction. After reduction, adequate stress roentgenograms are obtained to detect lateral instability in the collateral ligaments. Furthermore, dorsal stability must be verified. If the proximal phalanx can be readily dislocated dorsally, the intrinsic muscles are torn and should be repaired. Instability after pure dorsal dislocations is uncommon. Postreduction roentgenograms verify proper positioning of the joint surfaces, width of joint space, and poCum

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793

FIG. 34. The anterior oblique ligament is reconstructed according to the method of Littler with a portion of the flexor carpi radialis tendon. (Redrawn from Littler; From Weeks PM, Pin PG. In: Jurkiewicz MJ, Kriezek TJ, Mathes SJ, Ariyan S. Plastic surgery: principles and practice. St. Louis: Mosby, 1990:709.)

sitioning of the sesamoids. In pure dislocations of the proximal phalanx (in the absence of collateral ligament disruption or intrinsic muscle disruption), excellent results can also be expected from splinting the properly reduced joint in slight flexion for 3 weeks. Operative intervention in dorsal dislocations is indicated in the following situations: (1) when the dislocation is irreducible or the joint space is abnormally wide after reduction, (2) when the joint is unstable in the flexion-extension plane; careful attention must be paid to the positioning of the sesamoid bones on roentgenogram, and (3) when dislocations after reduction exhibit lateral instability of greater than 40 degrees with radial or ulnar stress. Surgical exposure is gained through a transverse incision along the thumb’s most proximal skin crease. The incision is curved proximally along the metacarpal. Any structures trapped within the joint space are extracted and repositioned, and the tension on the dislocated proximal phalanx is reduced by flexing the carpometacarpal joint, applying traction on the proximal phalanx, and gently flexing the proximal phalanx. Dorsal and lateral stability of the joint must be inspected. If the joint is unstable dorsally, the adductor pollicis and flexor pollicis brevis muscles are exposed to determine the extent of injury so that they can be repaired. If the volar plate has been avulsed from the proximal phalanx, it is reattached with the pull-out wire technique. Disruption of the tendons at their insertion into the sesamoids is repaired. When lateral instability is present, the disrupted 794

Cum

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1993

collateral ligament is repaired. Immobilization in slight flexion for 3 weeks is sufficient. Excellent results are obtained by either surgical repair or splinting the anatomically reduced joint in slight flexion for 3 weeks. Hyperextensibility to stress test in itself does not justify open reduction because many individuals can voluntarily and painlessly hyperextend their thumb MP joints to 4.5 or even 60 degrees yet have no clinical weakness or subsequent degenerative changes. MP Joint: Volar Dislocation.-When the. proximal phalanx is displaced volar to the metacarpal head and telescopes into the palm, the collateral ligaments have been disrupted and the posterior joint capsule is torn. Membranous attachments of the volar plate may be intact. Closed reduction can be readily accomplished. Stress roentgenograms are obtained to determine the integrity of the collateral ligaments. Operative intervention is indicated if the ulnar collateral ligament is disrupted. Otherwise, the joint is held in 30 degrees of flexion as the collateral ligaments heal. Active motion is begun early. MP Joint: Lateral Dislocation.-The factors contributing to lateral stability of the MP joint include: (1) the broad head of the metacarpal, (2) the radial and ulnar collateral ligaments, (3) the accessory collateral ligament and volar plate, and (4) the intrinsic muscles inserting into the sesamoids, proximal phalanx, and extensor apparatus. These features provide great stability to the joint, yet dislocation is more frequent at this joint than in the MP joints of all the fingers, The dislocation is frequently reduced by the patient pulling on the thumb. When the patient is seen in the emergency department, the joint is tender and swollen but in normal alignment. Flexion and extension are normal; however, lateral instability may be demonstrated. To state conclusively that the collateral ligaments have not been ruptured, the thumb must be anesthetized and the collateral ligaments must be tested again. If significant lateral deviation is noted, stress roentgenograms are obtained. Complete rupture of a collateral ligament must occur before significant lateral displacement is possible. The joint deviates more than 40 degrees when total disruption of a collateral ligament has occurred. Roentgenograms may reveal a fragment of bone at the base of the proximal phalanx, indicating ligament detachment (Fig. 35). The radially directed stress draws the aponeuroses of the adductor pollicis taut across the joint capsule, squeezing the collateral ligament proximally. This doubles the ligament onto itself with the free end pointing proximally, a situation that does not promote adequate healing of the ligament head. Malpositioning has been reported in 25 of 39 patients operated on for ulnar collateral ligament tears.30 Consequently, all thumb MP joints exhibiting a major disruption of the ulnar collateral ligament (greater than 40 degrees of lateral motion on Curr

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795

See legend 796

on opposite

page. Curr

Probl

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1993

stress roentgenograms) should undergo operative repair. Surgical exposure is gained through a curved dorsal ulnar incision over the MP joint. The folded collateral ligament is identified at the proximal end of the adductor aponeurosis. This aponeurosis is divided parallel to the fibers of the extensor pollicis longus tendon. As the adductor aponeurosis is reflected, the frayed ends of the ligament and its detachment site on the proximal phalanx are exposed. The collateral ligament is reattached to the proximal phalanx with the pull-out wire technique. The adductor aponeurosis is repaired and the MP joint is immobilized in slight flexion and ulnar deviation with a Kirschner wire. In the series referred to previously, all patients obtained excellent results for stability and pinch strength and were free of pain. Fingers znterphalangeal Joint.-Contributing to the stability of the interphalangeal joint are (1) the broad insertions of the flexor and extensor tendons spanning the joint, (2) the short, thick collateral ligaments, (3) the volar plate, (41 snug fixation of the skin envelope, and (5) single plane of joint mobility. Dislocation requires major ligament rupture, yet the flexor and extensor tendon insertions almost always remain intact. Closed reduction is readily accomplished. Postreduction roentgenograms must be obtained for verification that joint congruity has been reestablished. The joint is mobilized within 48 hours to prevent stiffness. Carpometacarpal Joint.-Dislocation of the metacarpal base is not uncommon. Most frequently, the dislocation is in a dorsal direction in response to a volar force (Fig. 36). Roentgenographic examination in the true lateral position is essential for making this diagnosis. Closed reduction is usually possible, yet a significant incidence of instability and recurrent subluxation necessitates internal fixation by inserting a Kirschner wire transversely into the adjacent stable metacarpal. Six weeks of immobilization is adequate. Failure to obtain complete reduction often leaves the patient with a weak grip, a tender bony prominence, and persistent pain. Carpometacarpal dislocations of the ulnar side of the hand are generally reduced with ease, but if closed reduction is incomplete, open reduction and Kirschner wire fixation is necessary. If open reduction is not required, then closed reduction and percutaneous insertion of a Kirschner wire through the metacarpal into the normal adjacent FIG. 35. The bony thumb have avulsed the joint. Curr

Probl

Surg,

attachments a segment

August

1993

of the medial of bone (arrow)

collateral ligament from the proximal

at the MP joint of the phalanx, destabilizing

797

FIG. 36. A, The metacarpals of all the fingers are dislocated dorsally (single arrow), as noted on a lateral view. A fracture at the base of the long finger metacarpal is evident (double arrow). B, An anteroposterior view reveals overlap at the carpometacarpal joints (arrows) associated with the dislocation.

metacarpal base ensures maintenance mobilization is required for stability.

of reduction.

Six weeks of im-

MP Joint.-Dorsal dislocation of the base of the proximal phalanx at the MP joint occurs most frequently in the index finger. The proximal phalanx is positioned atop the metacarpal head (Fig. 37). The volar plate of the joint is disrupted most frequently from its loose, filmy attachments to the metacarpal but remains attached to the proximal phalanx. The volar plate follows the proximal phalanx dorsally and is usually found dorsal to the metacarpal head. The collateral ligaments are lax during this displacement and may not be ruptured. Occasionally, however, the radial collateral ligament tears, resulting in ulnar deviation of the finger. The flexor tendons are taut as a result of the dislocation and slip over the ulnar side of the smooth metacarpal head. This ulnar displacement occurs because the intermetacarpal ligament that inserts into the proximal fibroosseous tunnel is present on the ulnar side of the index finger but absent from the radial side. The lumbrical muscle encircles the metacarpal head on its radial side and the palmar fascia completes the encirclement of the metacarpal head proximally (Fig. 38). Closed reduction is generally impossible and should not be pursued. For operative reduction a volar incision is made, exposing the 798

Cur-r

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1993

FIG. 37. The proximal phalanx is dislocated dorsally (arrows), overlaps, and is parallel to the metacarpal producing the bayonet deformity. (From Weeks PM, Pin PG. In: Jurkiewicz MJ, Krizek TJ, Mathes SJ, Ariyan S. Plastic surgery: principles and practice. St. Louis: Mosby, 1990:712.)

prominence of the metacarpal head. After the skin is reflected proximal to the metacarpal neck, the palmar fascia is split longitudinally to expose the lumbrical muscle and flexor tendon sheath. The taut, long flexor tendons on the ulnar side of the metacarpal head are released by incising the flexor sheath along the proximal phalanx. As the tendon pull is relaxed, the volar plate can be extracted from its dorsal location and repositioned. Distal traction permits reduction of the proximal phalanx. Fixation of the volar plate to the metacarpal or the deep fascia discourages dorsal instability. Immobilization in 60 degrees of flexion prevents significant shortening of the torn collateral ligaments as they heal. Dorsal dislocation of the proximal phalanx in the little finger is less frequent than in the index finger. The anatomic disarrangement is similar to that seen with the index finger, except that the flexor tenCurr

Probl Surg,

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1993

733

Lumbrical

muscle

FIG. 38. A, The flexor tendons are displaced to the ulnar side of the metacarpal head. B, The lumbrical muscle is displaced to the radial side of the metacarpal head. The volar plate is displaced between the articular surfaces, preventing reduction.

dons of the little finger are displaced to the radial side of the metacarpal head and the abductor digiti quinti tendons complete the encirclement of the metacarpal head on the ulnar side. Open reduction is required. Dislocation at the long or ring MP joint is rare because of the presence of the transverse metacarpal ligament on both sides of these joints. PIP Joints.-Dislocations sal, or volar direction.

of the PIP joint

may be in a lateral,

dor-

LATERAL DISLOCATION.Collateral ligament injuries of the PIP joints of the fingers are not uncommon. Frequently, they are the result of athletic injuries. Collateral ligament injuries are caused by abduction or adduction forces applied to the extended finger and are characterized clinically by unilateral pain, swelling, and sharply localized tenderness. Stress roentgenograms of the injured joint should be obtained and, if abnormal, compared with those of the corresponding finger joint of the uninjured hand. Severe tenderness may necessitate anesthesia to overcome muscle spasm. Partial tears of the ligament are dif800

Curr

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1993

ferentiated from complete tears by the degree of lateral mobility in the joint. Partial tears of the ligament usually cause pain, swelling, and localized tenderness, with minimal lateral instability on stress roentgenograms. Partial tears require early mobilization. Complete ligament tears, inadequately treated, result in disability of the finger by continued swelling, stiffness, and sensitivity to minor trauma. Successful operative repair of ruptured collateral ligaments has been reported in 14 of 18 patients.31 The radial collateral ligament was ruptured in 1.5 patients, and the ulnar collateral ligament was ruptured in three patients. In each case, the ligament had disrupted from its attachment to the proximal phalanx. The ligament was dislocated into the PIP joint in seven patients. Operative repair was accomplished with the pull-out wire technique and immobilization of the PIP joint in full extension was maintained for 3 or 4 weeks with a plaster cast. Within 12 to 16 weeks, motion was regained and no patient had lost more than 10 degrees of flexion or extension. DORSALDmocmON.-FOr dorsal dislocation to occur at the PIP joint, the volar plate must be detached, either from the base of the middle phalanx or from the neck of the proximal phalanx (Fig. 39). Most frequently, the disruption occurs at its insertion into the middle phalanx. The tear may extend posteriorly, dividing the collateral ligament into segments parallel to the direction of its fibers. The volar plate thus maintains its attachment to the proximal phalanx and its lateral attachments to the accessory collateral ligament. A segment of the proper collateral ligaments may maintain its attachments to the proximal phalanx, while the remaining segment is attached to the anterolateral surface of the dorsally displaced middle phalanx. When the middle phalanx is dislocated dorsally, the collateral ligaments are slack. Traction and gentle flexion facilitate reduction of the dislocation. If the collateral ligament attachments between the proximal

FIG. 39. The most common

dislocation at the PIP joint occurs dorsally. The volar plate attachments are disrupted distally. (From Weeks PM, Pin PG. In: Jurkiewicz MJ, Krizek TJ, Mathes SJ, Ariyan S. Plastic surgery: principles and practice. St. Louis: Mosby, 1990:714.)

CurrProblSur5

Au@st1993

801

phalanx head and the middle phalanx base are intact, the reduction will be stable. Early mobilization with limited extension is permitted. If the collateral ligament is torn from its insertion, open reduction and direct suture are preferred; the volar plate should be repaired at the same sitting. VOIARDISMGWION.-R~~~~~~ of the central slip of the extensor hood, identified at surgical exploration or by clinical examination, was reported in five consecutive cases of volar dislocation at the PIP joint (Fig. 40).32 All other cases treated by closed reduction and immobilization exhibited some dysfunction in the extensor apparatus (e.g., boutonniere deformity). Rupture of the central slip and triangular ligament predisposes toward development of a boutonniere deformity unless operative repair is accomplished. Consequently, an anterior dislocation of the PIP joint should be viewed as a disruption of the central tendinous slip, an avulsion of the collateral ligament (which may be displaced between the lateral band and the oblique retinacular ligament), a tear of the volar plate, and a bony dislocation. Prompt reduction and repair of these structures (middle slip, collateral ligament, and volar plate), combined with stabilization of the PIP joint in extension with a fine Kirschner wire for 6 weeks, is necessary. DIP Joint-Stability in the DIP joint is maintained by the flexor and extensor tendons bridging the joint, the short stout collateral ligaments, the dense volar plate, and the firm skin-ligament capsule. Dislocations are frequently compounded because of the firm skinligament capsule. Dorsal dislocations are associated with rupture of

FIG. 40. Volar dislocation by disruption TJ, Mathes 1990:714.) so.2

at the PIP joint is less common but is frequently accompanied of the extensor insertion. (From Weeks PM, Pin PG. In: Jurkiewicz MJ, Krizek SJ, Ariyan S. Plastic surgery: principles and practice. St. Louis: Mosby,

Curr

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1993

the collateral ligaments and the volar plate. Disruption of the extensor and flexor tendons is uncommon, with the long flexor usually displaced laterally. In twisting injuries, the extensor tendon insertion may be avulsed. Careful attention to the roentgenograms may reveal bone chips associated with the extensor tendon avulsion. If a significant-sized chip is associated with avulsion of the extensor tendon, then direct suture repair is indicated. If the profundus tendon is avulsed from the distal phalanx, it should be repaired. Reduction of the dislocation is readily accomplished with the patient under local anesthesia. Immobilization in 5 to 10 degrees of flexion with a transfixing Kirschner wire minimizes dressing needs. In the absence of extensor tendon injury, active and passive motion is begun after 3 to 4 weeks of immobilization. A stable functional joint can be expected.

RJZPLANTATION It should be remembered that the patient has the final say as to whether replantation should be performed. Replantation is indicated if the patient wants the part replanted and understands the consequences. With more recent evaluation of functional results after replantation, the following guidelines have been developed.33 If a single digit is amputated distal to the PIP joint, it can be replanted with a good functional result. If a single digit is amputated through or proximal to the PIP, the functional results are not nearly as good and completion of the amputation is recommended in many centers. When two or more fingers are amputated proximal to the PIP joint, replantation is indicated. When any portion of the thumb is amputated, replantation is indicated. More proximal amputations have been replanted with good results, especially at the wrist level (Fig. 41). Unfortunately, in complete amputation above the elbow in adult patients, functional recovery in the hand is inadequate. Replantations at the arm level are controversial, but pressure from the patient and the family is such that it is routinely performed. Replantation at the proximal arm level can be performed anticipating late amputation of the hand and fitting of a prosthesis at the distal forearm level after elbow flexion has been restored. This is often a difficult decision for the patient. Factors affecting the success of replantation include the age of the patient, the type of amputation, the level of amputation, and the general health of the patient. When all factors are equal, the younger patient has a better prognosis for functional recovery. Successful limb replantation is dependent on initial limb management, ischemia time, technical abilities of the surgeons, and postoperative management. The limb ‘should be cooled as quickly as possible to slow muscle necrosis. Perfusion of the amputated part with heparin Cur-r mob1

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1993

803

FIG. 41. A, The amputated hand has been maintained in a cold environment before replantation. B, Full extension of the fingers and thumb has been regained. C, The patient is able to flex the fingers and thumb fully and has slight wrist flexion.

in 10% dextran has been recommended but is not universally accepted because perfusion of the vessels can cause direct intimal injury.34 Decompressive incisions are required because of postoperative edema. Initially, the bones are shortened and internally fixed. Vascular shunts are used for arm amputations. The vessels are repaired and circulation is established. Nerve repair is performed at the same sitting, except in traction injuries when the ends are approximated. It is important to anticipate the extent of postoperative edema because extensive fasciotomies are usually required. Early passive motion of distal joints is important in maintaining supple joints. The contraindications to replantation are (1) life-threatening associated injuries, (2) serious medical illnesses, (3) atherosclerosis of the digital vessels, (4) severe crush or avulsion injury of the part, (5) multiple-level amputations with crushing of the tissues, (6) an index finger with injured MP joint, (7) prolonged warm ischemia time, (8) poor patient motivation, and (6) impaired patient mental status (for example, psychosis). Replantation is a highly specialized procedure 804

Curr

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1993

FIG. 42. A, The skin of the ring finger,

including the nail and nailbed, has been completely avulsed except for the digital nerves, which have been severely stretched. B, The skin cocoon has been revascularized and assumes normal coloration. C, Flexion at 7 days provides a good functional result. (From Weeks PM, Young VL. Revascularization of the skin envelope of a denuded finger. Plast Reconstr Surg 1982;69:527-31.)

Curr

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1993

80.5

that should be performed only by individuals well versed in the technical aspects and will not be discussed in further detail. Avulsion injuries such as ring avulsion present unique problems because the surgeon is left with the functioning units of bones, joints, neurovascular bundles, tendons, and the tendon sheath devoid of coverage (Fig. 42). Earlier attempts to provide coverage with pedicle flaps were unsatisfactory and amputation was recommended. Recently, however, revascularization of the avulsed skin cover has been accomplished with good functional results.35 SUMMAFkY A systematic approach to the injured hand has been presented that ensures no injuries are overlooked and provides the basis for a reconstructive approach. This scheme is tissue oriented, first evaluating injury to the vasculature, then to the skin, bone, joint, nerve, and tendon units. The most complex injuries can be thoroughly evaluated and properly treated with this method. REFERENCES

1. American College of Surgeons. Early care of the injured patient. 2nd ed. Philadelphia: WB Saunders, 1976. 2. Sanford JP. Guide to antimicrobial therapy. Dallas: Antimicrobial Therapy, Inc., 1993:31-32. 3. Gilula LA, Destouet JM, Weeks PM, et al. Roentgenographic diagnosis of the painful wrist. Clin Orthop 1384;187:52- 64. 4. Entin MA. Salvaging the basic hand. Surg Clin North Am 1968;48:1063-81. 5. Holden CE. The pathology and prevention of Volkmann’s ischaemic contractuna. J Bone Joint Surg Br 1979;61:296- 300. 6. Gelberman RH, Akeson WH. Decompression of forearm compartment syndrome. Clin Orthop 1978;134:225-9. 7. Lineaweaver W, McMorris S, Saucy D, Howard R. Cellular and bacterial toxicity of topical antimicrobials. Plast Reconstr Surg 1985;75:394-6. 8. Wilgis EFS. Observations on the effects of tourniquet ischemia. J Bone Joint Surg Am 1971;53:1343-52. 9. Sunderland S, Bradley KC. The perineurium of peripheral nerves. Anat Ret 1951;113:125. 10. Watchmaker GP, Gumucio CA, Crandall RE, Vannier MA, Weeks PM. Fascicular topography of the median nerve: a computer based study to identity branching patterns. J Hand Surg Am 1991;16:53-9. 11. Lehman RA, Hayer GJ. Degeneration and regeneration in peripheral nerve. Brain 1967;90285-96. 12. Seddon HJ. Three types of nerve injury. Brain 1943;66:237- 88. 13. Sunderland S. A classification of peripheral nerve injuries producing loss of function. Brain 1951;74:491- 516. 14. Dellon AL. Clinical use of vibratory stimuli to evaluate peripheral nerve injury and compressive neuropathy. Plast Reconstr Surg 1980;65:466-76. 15. Van Beck A, Glover J. Primary or delayed primary neurorrhaphy in rat sciatic nerve. J Surg Res 1975;18:335- 9. 606

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16. Kline DG, Hackett E. Reappraisal of timing for exploration of civilian peripheral nerve injuries. Surgery 1975;78:54- 65. 17. Millesi H, Meisal G, Berger A. Further experience with interfascicular grafting of the median, ulnar, and radial nenres. J Bone Joint Surg Am 1976;50:20918.

18. Higgs P, Wray RC, Weeks PM. Rate of bursting strength gain in repaired nerves. Ann Plast Surg 1979;3:338-40. 19. Mukherju SR. Tensile strength of nerves during healing. Br J Surg 1953;1192:192-5. 20. Leddy JP, Packer JW. Avulsion of the profundus insertion in athletes. J Hand Surg 1977;2:66-9. 21. Helal B, Chen SC, Iwegbu G. Rupture of the extensor pollicis longus tendon in undisplaced Colles’ type of fracture. Hand 1982;14:41-7. 22. Wray RC, Holtmann B, Weeks PM. Clinical treatment of partial tendon lacerations without suturing and with early motion. Plast Reconstr Surg 1977;59:231-40. 23. Lee H. Double loop locking suture: a technique of tendon repair for early active mobilization. J Hand Surg Am 1990;15:945-58. 24. Salter RB, Harris RW. Injuries involving the epiphyseal plate. J Bone Joint Surg Am 1963;45:587-622. 25. Griffiths JC. Fracture at the base of the first metacarpal bone. J Bone Joint Surg Br 1964;46:712- 9. 26. Gedda KO. Studies on Bennett’s fracture: anatomy, roentgenology, and therapy. Acta Chir Stand Suppl 1954;193:5-114. 27. Gedda KO, Moherg E. Open reduction and osteosynthesis of the so-called Bennett’s fracture in the carpometacarpal joint of the thumb. Acta Orthop Stand 1953;22:249-57. 28. McCue FC. Athletic injuries of the proximal interphalangeal joint requiring surgical treatment. J Bone Joint Surg Am 1970;52:937-56. 29. Eaton RG, Littler JW. Ligament reconstruction for the painful thumb carpometacarpal joint. J Bone Joint Surg Am 1973;55:1655-66. 30. Stener B. Displacement of the ruptured ulnar collateral ligament of the metacarpophalangeal joint of the thumb. A clinical and anatomical study. J Bone Joint Surg Br 1962;44:869- 79. 31. Redler I, Williams JT. Rupture of a collateral ligament of the proximal interphalangeal joint of the finger: analysis of 18 cases. J Bone Joint Surg Am 1964;49:322-6. 32. Spinner M, Choa BY. Anterior dislocation of the proximal interphalangeal joint. J Bone Joint Surg Am 1970;52:1329- 35. 33. Urbaniak JR. To replant or not to replant? That is not the question. J Hand Surg 1983;8:507-8. 34. Tamai S. Twenty years’ experience of limb replantation-review of 293 upper extremity replants. J Hand Surg 1982;7:549-56. 35. Weeks PM, Young VL. Revascularization of the skin envelope of a denuded finger. Plast Reconstr Surg 1982;69:527-31.

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