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Fractures of the distal phalanx
FRACTURES OF THE DISTAL PHALANX FRANK
CHEN,
MD,
and LAWRENCE
H. S C H N E I D E R ,
MD
The exposed nature of the peripheral portion of the fingers make fractures of the distal phalanges the most common of workplace injuries. Most are simply treated by local wound care and protective splinting, both for comfort and to prevent further injury. Articular injuries, however, are more complex and require recognition by the primary examiner so that appropriate treatment can be applied.
KEY WORDS: fractures, distal phalanx, complications
Injuries to the distal phalanx are common because of the exposed nature of the peripheral portion of the working hand. Fractures of the distal phalanx make up the majority of hand fractures involved in industrial accidents. 1 In a study of worker's compensation cases, distal phalanx fractures accounted for 50% of treated fractures. 2 The treatment of these injuries is most often directed to the care of the associated soft tissue component rather than the fracture itself. Treatment of the fracture usually involves a period of protective splinting until comfortable and then subsequent mobilization. 3-7 On occasion, techniques of internal splinting can be used to aid soft tissue healing. 5 Certain distal phalangeal fractures, however, require operative treatment, such as those with an associated avulsion of the flexor digitorum profundus tendon, s These techniques as well as others applicable to the treatment of distal phalanx fractures are generally well accepted and noncontroversial, with the exception of the area of the mallet fracture, where some disagreement exists. Trauma to the distal phalanx is most often caused by a crush injury that is associated with significant soft tissue disruption, including nailbed damage, and can result in tissue loss. 6,9 Closed injuries to the distal phalanx can be very painful secondary to hemorrhage into the unyielding fibrous septa of the pulp and into the nailbed. When there is a subungual hematoma, pressure can be relieved by drainage by a perforation of the nail with a needle or heated paperclip. 3,~° More recently we have used batterypowered cautery, which allows for drainage of the nailbed without the need to put pressure on the finger, and therefore drainage can be accomplished without causing discomfort to the patient. Treatment of the soft tissue injury is usually primary to care of distal phalangeal injury. Soft tissue debridement, repair, and loose closure followed with splinting is the usual treatment in the nondisplaced nonarticular distal phalanx fracture. Reduction is often unnecessary even in the situation of comminuted or splayed bone. The splint functions to provide comfort and protection from further From The Division of Hand Surgery, Department of Orthopaedic Surgery, Thomas Jefferson University Hospital, Philadelphia, PA. Address reprint requests to Lawrence H. Schneider, MD, The Philadelphia Hand Center, 901 Walnut St, Philadelphia, PA 19107. Copyright © 1997 by W.B. Saunders Company 1048-6666/97/0702-0001$05.00/0
injury. A foam-backed aluminum splint can be used in either a dorsal or palmar position at the middle and distal phalanges. It is not usually necessary to splint the proximal interphalangeal joint, but in more severe injuries, the splint can be extended to include the proximal joint for the first week to provide additional comfort. The classification of distal phalanx fractures can be divided into: s (1) distal-tuft fractures, (2) central-shaft fractures, and (3) proximal articular fractures. The tuft fracture itself can be either a simple transverse (Fig 1) or a comminuted fracture (Fig 2). Both can be treated with protective splinting with attention generally directed to the soft tissue injury. These fractures often heal by fibrous union resulting in clinical stability and excellent function despite a radiograph that shows no evidence of bony union even months after injury. This suggests that the surgeon should not rely on radiographs in these cases after the initial films are made. The rehabilitation of these injuries is directed toward restoring distal interphalangeal joint range of motion and desensitization of the healed soft tissue. Shaft fractures result from crush injuries sustained at a more proximal level than those of the tuft. They are more commonly transverse but can sometimes be longitudinal, depending on the direction of the injuring force. If sufficient soft tissue stability exists in the event of a nondisplaced or minimally displaced fracture, these injuries can be treated in similar fashion to tuft fractures. If the soft tissue injury is significant, internal splinting is considered to provide stability for wound healing. Either a Kirschner wire or a 20-gauge hypodermic needle on a syringe can be drilled across the fracture site to provide stability. (Fig 3). The internal splint device is usually left in place for 3 to 4 weeks. Treatment of shaft fractures with these methods is infrequently needed and should be reserved for selected unstable injuries with major soft tissue disruption. Articular fractures occur by a mechanism other than crush injuries. These injuries are usually closed and are separable into palmar, dorsal, or epiphyseal injuries. 5,8,11
PALMAR ARTICULAR
FRACTURES
The classic description of this injury involves the football tackler tightly grasping the jersey of an opponent as the latter pulls away. A closed avulsion injury of the flexor digitorum profundus (FDP) occurs as active finger flexion
Operative Techniques in Orthopaedics, Vol 7, No 2 (April), 1997: pp 107-115
107
Type l These injuries result in retraction of the tendon end to the level of the palm with rupture of both vinculae. A fracture fragment is not usually associated with this injury type. Surgical reattachment of the FDP is recommended within the first 2 weeks of injury. ~7 The repair demands reattachment of the profundus to bone, and a Bunnell pullout technique is used in these type I injuries. I8
Type II A small bone fragment is seen retracted to the proximal interphalangeal joint (PIP) level (Fig 4). The long vinculum is still intact, and repair can usually be accomplished up to about 4 weeks postinjury. In the surgical treatment of these injuries, a volar zigzag incision is made on the affected finger to expose the flexor tendon apparatus. 18A transverse incision is made in the flexor sheath just distal to the A-2 pulley to expose the avulsed tendon end usually held in this location by the intact long vinculum. The tendon end with its associated bony fragment is then passed beneath the sheath and pulleys to the level of the distal phalanx for reinsertion. Use of a pliable catheter passed retrograde along the intended tendon tract may be helpful on occasion. The tendon is then reinserted using the Bunnell pullout technique. Either the classic wire pullout or a modification 18using the 3-0 prolene can be used. The latter allows for removal by pulling distally on the suture and
Fig 1. The tuft injury can present as a simple transverse fracture at the tip of the distal phalanx.
is subjected to a counter force that forces the distal phalanx into extension. The most commonly injured digit is the ring finger. Several explanations have been offered to explain this digit's predisposition for this problem. It was shown experimentally by Manske and Lesker 12that the ring finger FDP insertion is weaker compared with that insertion in other digits. Gunter 13 believed that the existence of a common flexor muscle belly to the middle, ring, and small finger makes the ring finger more vulnerable, and Leddy 14 attributed the lack of independence of ring finger extension as the reason for its susceptibility to this injury. Radiographs of the involved finger may be normal which can result in the misdiagnosis of "jammed or sprained finger." This then leads to inappropriate or no treatment. Awareness of this injury and an appropriate history with careful examination for active DIP joint flexion are critical to avoid missing the diagnosis, which will benefit from early surgical treatment. A delay in diagnosis will create treatment problems because with time it becomes more difficult to bring the injured FDP tendon out to the distal phalanx. In addition, early restoration of FDP function has resulted in better distal joint flexion. 15 Though rare, acute vascular compromise of the digit has been reported after FDP avulsion, necessitating emergent operative intervention. 16 Leddy and Packer 17 described three types of avulsion injuries at the FDP insertion:
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Fig 2. Comminuted fracture of the distal tuft. CHEN AND SCHNEIDER
Fig 3. (A) Severe crush injury with significant soft tissue injury with instability. (B) A 20-gauge hypodermic needle is driven across the fracture under local anesthesia, (C) Radiograph with the needle in place.
avoids some of the problems associated with the wire technique, which pulls proximally against the juncture. In the modified technique, a 3-0 double-armed suture is secured to the distal end of the graft with a criss-cross stitch. The needle ends are then cut off, and the sutures are then threaded through a Keith needle placed through the middle portion of the nail into a hole in the distal phalanx previously created in the volar cortex by a bone awl and curette. The tendon end is then fed into the medullary canal and pulled tightly into the bone. The suture ends are then tied over a button on the nail. A strip of fine mesh gauze is then wrapped beneath the button to further tighten this system. Active motion exercises are initiated at 3 weeks after a period of protected mobilization. The FRACTURES OF THE DISTAL PHALANX
Prolene stitch or wire can be removed at 4 weeks. This method can be applied to most type II injuries; however, the surgeon must very carefully evaluate the posture of the finger before closure. If excessive flexion is noted intraoperatively after the repair, the procedure should be abandoned, and another technique may be applied such as a tendon graft in one or two stages, is
Type III These injuries have an associated large bony fragment that will not retract too far proximally because of the size of the fragment, which usually settles at the A-4 pulley. A lateral radiograph will show this large fragment just proximal to
109
Fig 4. (A) Type 2 injury. Loss of active flexion of the long finger at the distal joint secondary to avulsion injury of by the flexor digitorum profundus. (B) Radiograph shows defect in the palmar base of the distal phalanx with the fragment seen proximally at the proximal phalanx. (C) The fragment and the distal tendon end have been retrieved and will be reattached to the distal phalanx. (C and D) FulB function in extension and flexion at 6 months.
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CHEN AND SCHNEIDER
Fig 5. (A) Type 3 injury. Loss of flexion at the distal joint of the finger. (B) Radiographs show a large fragment off the distal phalanx. The profundus tendon is attached to the bone fragment, (C) Open reduction with wire pullout suture and Kirschner wire reestablishes the tendon insertion. (D and E) Range of motion in the early postoperative period.
FRACTURES OF THE DISTAL PHALANX
111
the distal interphalangeal (DIP) joint (Fig 5). In type II[ injuries, both vinculae are usually intact and, because of their proximity to the insertion, time for repair is not as critical. Treatment of these injuries is by open reduction and internal fixation, using the pullout suture technique where the wire or Prolene can incorporate the fracture fragment and pull it into its bed. Interfragmentary screw or Kirshner wire fixation of the this fragment is sometimes necessary. A variant of type III injuries has been recognized by Robins and Dobyns ~9and Smith. 2° In this rare situation, a large bony fragment is held up at the level of the A-4 pulley, but in addition the tendon has become detached from the fragment and has retracted proximal to the PIP joint or into the palm. This will require treatment of both the tendon rupture and the fracture. It is not possible to predict this occurrence by clinical examination and will only be discovered at the time of operative repair. Open reduction and internal fixation using both Kirshner wires and the pullout technique can be used to address this injury (Fig 6).
DORSAL ARTICULAR FRACTURES--MALLET FRACTURES Sudden forced flexion of the distal phalanx during active extension can result in an injury to the extensor mechanism at the DIP joint with an associated articular fracture. This avulsion injury has been called the "mallet fracture" and has been in some appearances the subject of controversy with regard to treatment methods. All agree that undis-
placed mallet fractures can be treated by splinting the distal joint in an extension splint for 6 to 8 weeks. However, the treatment of displaced mallet fractures with a significant bony fragment is the focal point of debate. This is attested to by the multitude of articles offering different operative methods for the treatment of this lesion. Most authors have limited their operative treatment to fractures that constitute greater than one third of the articular surface and that do not completely reduce when splinted in extension. 1°,21Stark et a]22 reported excellent postoperative function in 36 mallet fractures treated with meticulous open reduction and internal fixation. Horiuchi, 23 however, noted limited range of motion despite a pain-free joint after open reduction, internal fixation (ORIF) of 12 displaced mallet fractures. In a series of mallet fractures treated by the senior a u t h o r , 24 it was shown that nonoperative treatment would be followed by excellent function regardless of the size of the fragment or amount of displacement. Even when the joint was subluxated closed, splinting could suffice. This was because of the ability of the distal phalanx to remodel in the healing period. 24 In the author's study, fractures were divided into three types: Type I: fracture without joint subluxation Type II: fracture with DIP subluxation Type III: epiphyseal injury All were further subtyped into A--fracture fragment involving less than one third of the articular surface, B--involving one third to two thirds of the articular
Fig 6. (A) A type 3 variant in which the articular surface is disrupted. In addition, the profundus tendon has separated from the bone fragments and was found proximal in the finger. (B) The joint has been reduced and blocked by the Kirschner wire, while the tendon has been reattached to the base of the distal phalanx. (C and D) Range of motion of the ring finger achieved at I year.
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CHEN AND SCHNEIDER
Fig 7, (A) Mallet fracture. The fragment involves more than one third of the base of the distal phalanx and is displaced. (B) The distal phalanx is supported by a dorsal aluminum splint. The fracture has not completely reduced. (C) Radiograph at 2 years. The joint has remodeled and motion is essentially full.
surface, and C--;mvolving greater than two thirds of the articular surface. Lesions in all groups had functionally good results with simple splinting. Bone remodeling occurred in all iniured digits with reconstitution of the articular surface and preservation of the joint space. A near-normal range of motion was achieved in all but one patient. The only consistent complication, if it could be called that, was a dorsal prominence at the fracture site, which is often present regardless of the method of treatment and is seen even in the presence of meticulous open reduction. At this time, on the senior author's service, all mallet fractures are treated closed with splinting in extension. Only the DIP joint need be immobilized, using either a dorsal or velar splint or a commercially available plastic splint (Stack). It is emphasized that splinting should be
without interruption throughout the 6- to 8-week healing period (Fig 7). Lange and Engber 25 brought to our attention the variation of this fracture that was caused by a hyperextension injury. The dorsal aspect of the base of the distal phalanx is crushed against the head of the middle phalanx, leading to a dorsal lip fracture that looks the same as the traditional mallet fracture. There is a tendency toward subluxation here if the fracture is treated in hyperextension. When we recognize this injury, we would still treat it nonoperatively but in mild flexion (10 °) in a DIP splint. Epiphyseal S e p a r a t i o n Fractures
A crush injury to the distal portion of a child's digit can sometimes result in an epiphyseal fracture, of the distal
Fig 8. (A) Injury has driven the phalanx into flexion. The bone has penetrated the skin. (B) The injury was reduced and has healed. One year later, radiograph shows that the epiphyseal line has closed. FRACTURES OF THE DISTAL PHALANX
113
Fig 9. (A) Epiphyseal separation distal phalanx. (B) Open reduction replaced the epiphysis anatomically. (C) The injury healed without incident, and the plate is still open at 3 years after injury.
phalanx. On presentation to the emergency ward, the proximal nail plate is often seen outside the nail fold, and a characteristic radiograph of this juxtaepiphyseal fracture will be seen 21 (Fig 8). Treatment of these injuries is closed
reduction and use of the nail as an external splint. In cases in which there is complete dislocation of the epiphysis, it will be necessary to perform ORIF with Kirshner wire fixation, which is added to provide added stability (Fig 9).
Fig 10. Nonunion of a distal phalangeal shaft fracture. This fracture was unstable and symptomatic. (B) Distal radius bone graft was held with two Kirschner wires. (C) Healed at 6 months. 114
CHEN AND SCHNEIDER
COMPLICATIONS Most complications are related to the soft tissue component of this injury Chronic pain can result from injury to the neurovascular structures. DaCruz et a126 reported that more than 70% of patients 6 months after distal phalanx fracture continued to have symptoms that affected their day-to-day activities. Cold hypersensitivity was reported in one in three pat:ients in that series. These problems can be addressed through desensitization therapy, local blocks, neuroma excision, or even a revision by amputation. Symptomatic nonunion of distal phalanx fractures is rare. In one case, a bone graft was used in a persistent n o n u n i o n of the shaft of t h e d i s t a l p h a l a n x (Fig 10). I n f e c t i o n after o p e n i n j u r y or after o p e r a t i v e t r e a t m e n t can be disastrous. Incision a n d d e b r i d e m e n t with antibiotic t r e a t m e n t w i l l likely a m e l i o r a t e this s i t u a t i o n . I n s o m e i n s t a n c e s , a m p u t a t i o n m a y b e n e c e s s a r y to c o n t r o l this p r o b l e m . I n c l u s i o n cysts h a v e b e e n k n o w n to o c c a s i o n a l l y o c c u r at the site of o p e n injury. 8 T r e a t m e n t of this cyst i n v o l v e s e x c i s i o n of the m a s s . I n the s i t u a t i o n of s y m p t o m atic p o s t t r a u m a t i c arthritis, j o i n t a r t h r o d e s i s is a u s e f u l a n d reliable t r e a t m e n t o p t i o n .
SUMMARY Fractures of the distal phalanx most commonly result from crush injuries. Fracture management is for the most part secondary to care for the surrounding soft tissue. Specific treatment for the fracture itself is infrequently needed. Displaced fractures of the volar articular surface, however, are associated with avulsion of the FDP, which requires surgical attention.. We have been pleased with the pullout technique to reattach this tendon and its accompanying bony fragment. Despite some disagreement, displaced mallet fractures are best treated by nonoperative means. After consolidation of distal phalanx fractures, patients may still complain of persistent problems usually related to the soft tissue component of the original injury.
REFERENCES 1. Absoud EM, Harrop SN: Hand injuries at work. J Hand Surg [Br] 9:211-215,1984 2. Butt WD: Fractures of the hand. I. Description. Can Med Assoc J 86:731-735,1962 3. Brown PW: The management of phalangeal and metacarpal fractures. Surg Clin North Am 53:1393-1437, 1973
FRACTURES OF THE DISTAL PHALANX
4. Burton RI, Eaton EG: Common hand injuries in the athlete. Orthop Clin North Am 4:809-838, 1973 5. Schneider LH: Fractures of the distal interphalangealjoint. Hand Clin 10:277-285,1994 6. Hubbard LF: Fractures of the hand and wrist, in Evarts CM (ed): Surgery of the Muculoskeletal System. New York, NY, Churchill Livingstone, 1983 7. Jupiter JB, Belsky MR: Fractures and dislocations of the hand, in Browner JD, Jupiter JB, Levine AM, et al (eds): Skeletal Trauma. Philadelphia, PA, Saunders, 1992 8. Schneider LH: Fractures of the distal phalanx. Hand Clin 4:537-547, 1988 9. Leddy JP: Avulsions of the flexor digitorum profundus. Hand Clin North Am 1:77-83,1985 10. Lister GD: The Hand: Diagnosis and Indications. New York, NY, Churchill Livingstone, 1993 11. Green DP, Rowland SA: Fractures and dislocations in the hand, in Rockwood CA, Green DP (eds): Fractures in Adults. Philadelphia, PA, Lippincott, 1991 12. Manske PR, Lesker PA: Avulsion of the ring finger flexor digitorum profundus tendon: An experimental study. Hand 10:52-55, 1978 13. Gunter GS: Traumatic avulsion of the insertion of the flexor digitorum profundus. Aust N Z Surg 30:1-8, 1960 14. Leddy JP: Flexor tendons: Acute Injuries, in Green DP (ed): Operative Hand Surg. New York, NY, Churchill Livingstone, 1993 15. Carroll RE, Match RM: Avulsion of the flexor profundus tendon insertion. J Trauma 10:1109-1118,1970 16. Gordon LM, Monsanto EH: Acute vascular compromise after avulsion of the distal phalanx with the flexor digitorum profundus tendon. J Hand Surg [Am] 12:259-261,1987 17. Leddy JP, Packer JW: Avulsion of the profundus tendon insertion in athletes. J Hand Surg [Am] 2:66-69, 1977 18. Schneider LH, Hunter JM: Flexor tendon injuries: Late reconstruction, in Green DP: Operative Hand Surgery. New York, NY, Churchill Livingston, 1993, chap 51 19. Robins PK, Dobyns JH: Avulsion of the insertion of the flexor digitorum profundus tendon associated with fracture of the distal phalanx: A brief review, in AAOS: Symposium on Tendon Surgery in the Hand. St. Louis, MO, CV Mosby, 1975 20. Smith IH: Avulsion of the profundus tendon with simultaneous intraarticular fracture of the distal phalanx: Case report. J Hand Surg [Am] 6:600-601,1981 21. Seymour N: Juxta-epiphyseal fracture of the terminal phalanx of the finger. J Bone Joint Surg 48:347-349,1966 22. Stark HH, Gainor BJ, Ashworth CR, et al: Operative treatment of the intra-articular fractures of the dorsal aspect of the distal phalanx digits. J Bone Joint Surg Am 69:892-896, 1987 23. Horiuchi Y, Itoh T, Sasaki K, et al: Dorsal dislocation of the DIP joint with fracture of the volar base of the distal phalanx. J Hand Surg [Br] 14:177-182, 1989 24. Wehbe MA, Schneider LH: Mallet fractures. J Bone Joint Surg Am 66:658-669,1984 25. Lange RH, Engber WD: Hyperextension Mallet finger. Orthopedics 6:1426-1431, 1983 26. DaCruz DJ, Slade RJ, Malone W: Fractures of the distal phalanges, l Hand Surg [Br] 13:350-352,1988
115
CHEN,
MD,
and LAWRENCE
H. S C H N E I D E R ,
MD
The exposed nature of the peripheral portion of the fingers make fractures of the distal phalanges the most common of workplace injuries. Most are simply treated by local wound care and protective splinting, both for comfort and to prevent further injury. Articular injuries, however, are more complex and require recognition by the primary examiner so that appropriate treatment can be applied.
KEY WORDS: fractures, distal phalanx, complications
Injuries to the distal phalanx are common because of the exposed nature of the peripheral portion of the working hand. Fractures of the distal phalanx make up the majority of hand fractures involved in industrial accidents. 1 In a study of worker's compensation cases, distal phalanx fractures accounted for 50% of treated fractures. 2 The treatment of these injuries is most often directed to the care of the associated soft tissue component rather than the fracture itself. Treatment of the fracture usually involves a period of protective splinting until comfortable and then subsequent mobilization. 3-7 On occasion, techniques of internal splinting can be used to aid soft tissue healing. 5 Certain distal phalangeal fractures, however, require operative treatment, such as those with an associated avulsion of the flexor digitorum profundus tendon, s These techniques as well as others applicable to the treatment of distal phalanx fractures are generally well accepted and noncontroversial, with the exception of the area of the mallet fracture, where some disagreement exists. Trauma to the distal phalanx is most often caused by a crush injury that is associated with significant soft tissue disruption, including nailbed damage, and can result in tissue loss. 6,9 Closed injuries to the distal phalanx can be very painful secondary to hemorrhage into the unyielding fibrous septa of the pulp and into the nailbed. When there is a subungual hematoma, pressure can be relieved by drainage by a perforation of the nail with a needle or heated paperclip. 3,~° More recently we have used batterypowered cautery, which allows for drainage of the nailbed without the need to put pressure on the finger, and therefore drainage can be accomplished without causing discomfort to the patient. Treatment of the soft tissue injury is usually primary to care of distal phalangeal injury. Soft tissue debridement, repair, and loose closure followed with splinting is the usual treatment in the nondisplaced nonarticular distal phalanx fracture. Reduction is often unnecessary even in the situation of comminuted or splayed bone. The splint functions to provide comfort and protection from further From The Division of Hand Surgery, Department of Orthopaedic Surgery, Thomas Jefferson University Hospital, Philadelphia, PA. Address reprint requests to Lawrence H. Schneider, MD, The Philadelphia Hand Center, 901 Walnut St, Philadelphia, PA 19107. Copyright © 1997 by W.B. Saunders Company 1048-6666/97/0702-0001$05.00/0
injury. A foam-backed aluminum splint can be used in either a dorsal or palmar position at the middle and distal phalanges. It is not usually necessary to splint the proximal interphalangeal joint, but in more severe injuries, the splint can be extended to include the proximal joint for the first week to provide additional comfort. The classification of distal phalanx fractures can be divided into: s (1) distal-tuft fractures, (2) central-shaft fractures, and (3) proximal articular fractures. The tuft fracture itself can be either a simple transverse (Fig 1) or a comminuted fracture (Fig 2). Both can be treated with protective splinting with attention generally directed to the soft tissue injury. These fractures often heal by fibrous union resulting in clinical stability and excellent function despite a radiograph that shows no evidence of bony union even months after injury. This suggests that the surgeon should not rely on radiographs in these cases after the initial films are made. The rehabilitation of these injuries is directed toward restoring distal interphalangeal joint range of motion and desensitization of the healed soft tissue. Shaft fractures result from crush injuries sustained at a more proximal level than those of the tuft. They are more commonly transverse but can sometimes be longitudinal, depending on the direction of the injuring force. If sufficient soft tissue stability exists in the event of a nondisplaced or minimally displaced fracture, these injuries can be treated in similar fashion to tuft fractures. If the soft tissue injury is significant, internal splinting is considered to provide stability for wound healing. Either a Kirschner wire or a 20-gauge hypodermic needle on a syringe can be drilled across the fracture site to provide stability. (Fig 3). The internal splint device is usually left in place for 3 to 4 weeks. Treatment of shaft fractures with these methods is infrequently needed and should be reserved for selected unstable injuries with major soft tissue disruption. Articular fractures occur by a mechanism other than crush injuries. These injuries are usually closed and are separable into palmar, dorsal, or epiphyseal injuries. 5,8,11
PALMAR ARTICULAR
FRACTURES
The classic description of this injury involves the football tackler tightly grasping the jersey of an opponent as the latter pulls away. A closed avulsion injury of the flexor digitorum profundus (FDP) occurs as active finger flexion
Operative Techniques in Orthopaedics, Vol 7, No 2 (April), 1997: pp 107-115
107
Type l These injuries result in retraction of the tendon end to the level of the palm with rupture of both vinculae. A fracture fragment is not usually associated with this injury type. Surgical reattachment of the FDP is recommended within the first 2 weeks of injury. ~7 The repair demands reattachment of the profundus to bone, and a Bunnell pullout technique is used in these type I injuries. I8
Type II A small bone fragment is seen retracted to the proximal interphalangeal joint (PIP) level (Fig 4). The long vinculum is still intact, and repair can usually be accomplished up to about 4 weeks postinjury. In the surgical treatment of these injuries, a volar zigzag incision is made on the affected finger to expose the flexor tendon apparatus. 18A transverse incision is made in the flexor sheath just distal to the A-2 pulley to expose the avulsed tendon end usually held in this location by the intact long vinculum. The tendon end with its associated bony fragment is then passed beneath the sheath and pulleys to the level of the distal phalanx for reinsertion. Use of a pliable catheter passed retrograde along the intended tendon tract may be helpful on occasion. The tendon is then reinserted using the Bunnell pullout technique. Either the classic wire pullout or a modification 18using the 3-0 prolene can be used. The latter allows for removal by pulling distally on the suture and
Fig 1. The tuft injury can present as a simple transverse fracture at the tip of the distal phalanx.
is subjected to a counter force that forces the distal phalanx into extension. The most commonly injured digit is the ring finger. Several explanations have been offered to explain this digit's predisposition for this problem. It was shown experimentally by Manske and Lesker 12that the ring finger FDP insertion is weaker compared with that insertion in other digits. Gunter 13 believed that the existence of a common flexor muscle belly to the middle, ring, and small finger makes the ring finger more vulnerable, and Leddy 14 attributed the lack of independence of ring finger extension as the reason for its susceptibility to this injury. Radiographs of the involved finger may be normal which can result in the misdiagnosis of "jammed or sprained finger." This then leads to inappropriate or no treatment. Awareness of this injury and an appropriate history with careful examination for active DIP joint flexion are critical to avoid missing the diagnosis, which will benefit from early surgical treatment. A delay in diagnosis will create treatment problems because with time it becomes more difficult to bring the injured FDP tendon out to the distal phalanx. In addition, early restoration of FDP function has resulted in better distal joint flexion. 15 Though rare, acute vascular compromise of the digit has been reported after FDP avulsion, necessitating emergent operative intervention. 16 Leddy and Packer 17 described three types of avulsion injuries at the FDP insertion:
108
Fig 2. Comminuted fracture of the distal tuft. CHEN AND SCHNEIDER
Fig 3. (A) Severe crush injury with significant soft tissue injury with instability. (B) A 20-gauge hypodermic needle is driven across the fracture under local anesthesia, (C) Radiograph with the needle in place.
avoids some of the problems associated with the wire technique, which pulls proximally against the juncture. In the modified technique, a 3-0 double-armed suture is secured to the distal end of the graft with a criss-cross stitch. The needle ends are then cut off, and the sutures are then threaded through a Keith needle placed through the middle portion of the nail into a hole in the distal phalanx previously created in the volar cortex by a bone awl and curette. The tendon end is then fed into the medullary canal and pulled tightly into the bone. The suture ends are then tied over a button on the nail. A strip of fine mesh gauze is then wrapped beneath the button to further tighten this system. Active motion exercises are initiated at 3 weeks after a period of protected mobilization. The FRACTURES OF THE DISTAL PHALANX
Prolene stitch or wire can be removed at 4 weeks. This method can be applied to most type II injuries; however, the surgeon must very carefully evaluate the posture of the finger before closure. If excessive flexion is noted intraoperatively after the repair, the procedure should be abandoned, and another technique may be applied such as a tendon graft in one or two stages, is
Type III These injuries have an associated large bony fragment that will not retract too far proximally because of the size of the fragment, which usually settles at the A-4 pulley. A lateral radiograph will show this large fragment just proximal to
109
Fig 4. (A) Type 2 injury. Loss of active flexion of the long finger at the distal joint secondary to avulsion injury of by the flexor digitorum profundus. (B) Radiograph shows defect in the palmar base of the distal phalanx with the fragment seen proximally at the proximal phalanx. (C) The fragment and the distal tendon end have been retrieved and will be reattached to the distal phalanx. (C and D) FulB function in extension and flexion at 6 months.
110
CHEN AND SCHNEIDER
Fig 5. (A) Type 3 injury. Loss of flexion at the distal joint of the finger. (B) Radiographs show a large fragment off the distal phalanx. The profundus tendon is attached to the bone fragment, (C) Open reduction with wire pullout suture and Kirschner wire reestablishes the tendon insertion. (D and E) Range of motion in the early postoperative period.
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the distal interphalangeal (DIP) joint (Fig 5). In type II[ injuries, both vinculae are usually intact and, because of their proximity to the insertion, time for repair is not as critical. Treatment of these injuries is by open reduction and internal fixation, using the pullout suture technique where the wire or Prolene can incorporate the fracture fragment and pull it into its bed. Interfragmentary screw or Kirshner wire fixation of the this fragment is sometimes necessary. A variant of type III injuries has been recognized by Robins and Dobyns ~9and Smith. 2° In this rare situation, a large bony fragment is held up at the level of the A-4 pulley, but in addition the tendon has become detached from the fragment and has retracted proximal to the PIP joint or into the palm. This will require treatment of both the tendon rupture and the fracture. It is not possible to predict this occurrence by clinical examination and will only be discovered at the time of operative repair. Open reduction and internal fixation using both Kirshner wires and the pullout technique can be used to address this injury (Fig 6).
DORSAL ARTICULAR FRACTURES--MALLET FRACTURES Sudden forced flexion of the distal phalanx during active extension can result in an injury to the extensor mechanism at the DIP joint with an associated articular fracture. This avulsion injury has been called the "mallet fracture" and has been in some appearances the subject of controversy with regard to treatment methods. All agree that undis-
placed mallet fractures can be treated by splinting the distal joint in an extension splint for 6 to 8 weeks. However, the treatment of displaced mallet fractures with a significant bony fragment is the focal point of debate. This is attested to by the multitude of articles offering different operative methods for the treatment of this lesion. Most authors have limited their operative treatment to fractures that constitute greater than one third of the articular surface and that do not completely reduce when splinted in extension. 1°,21Stark et a]22 reported excellent postoperative function in 36 mallet fractures treated with meticulous open reduction and internal fixation. Horiuchi, 23 however, noted limited range of motion despite a pain-free joint after open reduction, internal fixation (ORIF) of 12 displaced mallet fractures. In a series of mallet fractures treated by the senior a u t h o r , 24 it was shown that nonoperative treatment would be followed by excellent function regardless of the size of the fragment or amount of displacement. Even when the joint was subluxated closed, splinting could suffice. This was because of the ability of the distal phalanx to remodel in the healing period. 24 In the author's study, fractures were divided into three types: Type I: fracture without joint subluxation Type II: fracture with DIP subluxation Type III: epiphyseal injury All were further subtyped into A--fracture fragment involving less than one third of the articular surface, B--involving one third to two thirds of the articular
Fig 6. (A) A type 3 variant in which the articular surface is disrupted. In addition, the profundus tendon has separated from the bone fragments and was found proximal in the finger. (B) The joint has been reduced and blocked by the Kirschner wire, while the tendon has been reattached to the base of the distal phalanx. (C and D) Range of motion of the ring finger achieved at I year.
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Fig 7, (A) Mallet fracture. The fragment involves more than one third of the base of the distal phalanx and is displaced. (B) The distal phalanx is supported by a dorsal aluminum splint. The fracture has not completely reduced. (C) Radiograph at 2 years. The joint has remodeled and motion is essentially full.
surface, and C--;mvolving greater than two thirds of the articular surface. Lesions in all groups had functionally good results with simple splinting. Bone remodeling occurred in all iniured digits with reconstitution of the articular surface and preservation of the joint space. A near-normal range of motion was achieved in all but one patient. The only consistent complication, if it could be called that, was a dorsal prominence at the fracture site, which is often present regardless of the method of treatment and is seen even in the presence of meticulous open reduction. At this time, on the senior author's service, all mallet fractures are treated closed with splinting in extension. Only the DIP joint need be immobilized, using either a dorsal or velar splint or a commercially available plastic splint (Stack). It is emphasized that splinting should be
without interruption throughout the 6- to 8-week healing period (Fig 7). Lange and Engber 25 brought to our attention the variation of this fracture that was caused by a hyperextension injury. The dorsal aspect of the base of the distal phalanx is crushed against the head of the middle phalanx, leading to a dorsal lip fracture that looks the same as the traditional mallet fracture. There is a tendency toward subluxation here if the fracture is treated in hyperextension. When we recognize this injury, we would still treat it nonoperatively but in mild flexion (10 °) in a DIP splint. Epiphyseal S e p a r a t i o n Fractures
A crush injury to the distal portion of a child's digit can sometimes result in an epiphyseal fracture, of the distal
Fig 8. (A) Injury has driven the phalanx into flexion. The bone has penetrated the skin. (B) The injury was reduced and has healed. One year later, radiograph shows that the epiphyseal line has closed. FRACTURES OF THE DISTAL PHALANX
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Fig 9. (A) Epiphyseal separation distal phalanx. (B) Open reduction replaced the epiphysis anatomically. (C) The injury healed without incident, and the plate is still open at 3 years after injury.
phalanx. On presentation to the emergency ward, the proximal nail plate is often seen outside the nail fold, and a characteristic radiograph of this juxtaepiphyseal fracture will be seen 21 (Fig 8). Treatment of these injuries is closed
reduction and use of the nail as an external splint. In cases in which there is complete dislocation of the epiphysis, it will be necessary to perform ORIF with Kirshner wire fixation, which is added to provide added stability (Fig 9).
Fig 10. Nonunion of a distal phalangeal shaft fracture. This fracture was unstable and symptomatic. (B) Distal radius bone graft was held with two Kirschner wires. (C) Healed at 6 months. 114
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COMPLICATIONS Most complications are related to the soft tissue component of this injury Chronic pain can result from injury to the neurovascular structures. DaCruz et a126 reported that more than 70% of patients 6 months after distal phalanx fracture continued to have symptoms that affected their day-to-day activities. Cold hypersensitivity was reported in one in three pat:ients in that series. These problems can be addressed through desensitization therapy, local blocks, neuroma excision, or even a revision by amputation. Symptomatic nonunion of distal phalanx fractures is rare. In one case, a bone graft was used in a persistent n o n u n i o n of the shaft of t h e d i s t a l p h a l a n x (Fig 10). I n f e c t i o n after o p e n i n j u r y or after o p e r a t i v e t r e a t m e n t can be disastrous. Incision a n d d e b r i d e m e n t with antibiotic t r e a t m e n t w i l l likely a m e l i o r a t e this s i t u a t i o n . I n s o m e i n s t a n c e s , a m p u t a t i o n m a y b e n e c e s s a r y to c o n t r o l this p r o b l e m . I n c l u s i o n cysts h a v e b e e n k n o w n to o c c a s i o n a l l y o c c u r at the site of o p e n injury. 8 T r e a t m e n t of this cyst i n v o l v e s e x c i s i o n of the m a s s . I n the s i t u a t i o n of s y m p t o m atic p o s t t r a u m a t i c arthritis, j o i n t a r t h r o d e s i s is a u s e f u l a n d reliable t r e a t m e n t o p t i o n .
SUMMARY Fractures of the distal phalanx most commonly result from crush injuries. Fracture management is for the most part secondary to care for the surrounding soft tissue. Specific treatment for the fracture itself is infrequently needed. Displaced fractures of the volar articular surface, however, are associated with avulsion of the FDP, which requires surgical attention.. We have been pleased with the pullout technique to reattach this tendon and its accompanying bony fragment. Despite some disagreement, displaced mallet fractures are best treated by nonoperative means. After consolidation of distal phalanx fractures, patients may still complain of persistent problems usually related to the soft tissue component of the original injury.
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