Common Urgent Musculoskeletal Injuries in Primary Care

Prim Care Clin Office Pract 33 (2006) 751–777

Common Urgent Musculoskeletal Injuries in Primary Care Yvette L. Rooks, MD*, Brian Corwell, MD Department of Family Medicine, University of Maryland Medical Center, 29 South Paca Street, lower level, Baltimore, MD 21201, USA

Approximately 25% of patients seen in the primary care office complain of problems related to the musculoskeletal system. General knowledge of the musculoskeletal system is important for timely diagnosis and comprehensive treatment of patients, either by a primary care provider or in conjunction with an orthopedist. Accurate diagnosis, not definitive treatment, is the primary role of the primary care physician in the care of musculoskeletal injuries. Although musculoskeletal injuries are rarely life-threatening, they may be associated with other injuries that are. Injuries to muscle, bones, and joints may cause permanent disability that can, however, be minimized with timely appropriate care. This article is designed to provide primary care providers with a review of urgent treatment of specific common musculoskeletal injuries.

Evaluation of the patient who has acute shoulder pain Shoulder pain is a common complaint in both primary and emergency care. The pain may be traumatic or insidious, chronic or disabling. Patients who have true acute or traumatic pain are more likely to come to the emergency department than to the primary care office, whereas those whose pain occurs after minor falls and athletics mishaps, including fractures, dislocations, and soft-tissue injuries, may come to any medical facility. Acute pain originating within the shoulder usually appears suddenly after some traumatic event. Determining when and how the injury occurred is very important, as is determining the precise location, intensity, and pattern of radiation. The initial step in evaluating is to obtain a good history. Questions

* Corresponding author. E-mail address: [email protected] (Y.L. Rooks). 0095-4543/06/$ - see front matter Ó 2006 Elsevier Inc. All rights reserved. doi:10.1016/j.pop.2006.06.009 primarycare.theclinics.com

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should first be general. The second group of questions should be directed toward specific clinical entities suggested by the patient’s responses to the general questions. The clinical examination should include visual inspection for deformity, ecchymosis, atrophy, and asymmetry. Active and passive range of motion of the shoulder girdle should be assessed, and provocative tests that will provide a more focused evaluation should be used as well. A neurovascular evaluation of the upper extremity is essential to a thorough shoulder examination. To properly diagnose and treat shoulder pain, and to know when to refer for specialty consultation, the clinician must understand and be familiar with the functional anatomy of the shoulder, the common mechanisms of injury, the appropriate radiological studies, and available treatments. The shoulder is composed of the humerus, glenoid, scapula, acromion, clavicle, and surrounding soft-tissue structures. The shoulder region includes the glenohumeral joint, the acromioclavicular joint, the glenoclavicular joint, and the scapulothorasic articulation. Glenohumeral stability is the result of a combination of ligamentous and capsular constraints, surrounding musculature, and the glenoid labrum. Static joint stability is provided by the joint surfaces and the capsulolabral complex, and dymnamic stability by the rotator cuff muscles and scapular rotators [1]. Acromioclavicular joint injury A common injury among athletes and active patients is acromioclavicular (AC) sprain, also referred to as ‘‘shoulder separation.’’ AC joint injuries account for 12% of all dislocations of the shoulder girdle, and are more common in men than in women [2]. They are usually associated with contact sports, motor vehicle accidents, and falls. Acromioclavicular joint injury is associated with subsequent local pain. Tenderness, swelling, and often a deformity with prominence of the distal clavicle are seen. AC joint injuries are graded in severity according to the extent of ligamentous injury. Grade I represents an AC ligament sprain; Grade II, a complete ligament rupture, with a widened joint space. In a Grade III ligamentous injury, the AC and coracoid (CC) ligaments and their muscle attachments are totally disrupted, and the joint space is significantly widened. Grade IV injuries include the previous injuries, and, in addition, the clavicle is displaced posteriorily into or through the trapezius. In a Grade V injury, the distal clavicle is displaced superiorly, and in a Grade VI injury, the distal clavicle is displaced inferiorly. On examination, the AC joint is tender to palpation and painful on attempted shoulder motion. AC radiographs help determine the severity of the injury. Radiographs are likely to be normal with a Grade I injury. For appropriate management, one should evaluate for associated injuries, including sternoclavicular (SC) dislocation, and clavicle or coracoid fractures. All patients should be placed in a sling, both for comfort and to avoid further disruption of the injured joint.

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Patients who have Grade I and II injuries can be managed with rest, ice, and analgesics for 1 to 3 weeks. The patient may begin active range of motion of the arm when pain-free. Patients who have a Grade III sprain or higher should be referred to an orthopedist for consultation and possible surgical repair. Clavicle fracture Clavicle fractures account for 5% of all types of fractures, and are the most common type among children. Most clavicle fractures occur through the middle third of the clavicle. An indirect or direct blow to the shoulder causes fracture of the clavicle. Because the clavicle is directly beneath the skin, these fractures are relatively easy to diagnose. A radiograph should be taken to determine whether the patient has a displaced fracture of the proximal or distal clavicle, which may require a swifter referral to orthopedic care. A complete neurovascular examination of the upper extremities needs to be performed to rule out associated brachial plexus or vascular injury. The figure-of-eight bandage is the traditional method of treatment for fractures that occur through the middle third of the clavicle, but a simple sling is sufficient and can be an effective alternative. The primary intent is to reduce motion at the fracture site, in order to reduce the patient’s discomfort. Patients should wear the sling until a series of films indicate evidence of callus formation. Acute shoulder dislocations Glenohumeral dislocation is the most common shoulder dislocation, representing 95% of all shoulder injuries [2]. Acute disorders of the glenohumeral joint are usually the result of indirect forces applied to the joint. The shoulder can dislocate either anteriorly, posteriorly, or inferiorly. Anterior dislocations compose approximately 95% of such injuries, posterior and inferior dislocations making up the remaining 5%. In acute anterior dislocations the humeral head is forced out of the glenoid anteriorly and comes to rest beneath the coracoid process, clavicle, or glenoid. The humeral head usually is palpable anteriorly, and the diagnosis is often confirmed by locating a dimple in the skin beneath the acromion. Posterior dislocation of the shoulder joint is rare, and is frequently missed during initial evaluation. Typically, the patient holds the arm close to the body in abduction and internal rotation. Forward elevation is extremely limited. The physician should always look for possible related injuries, including proximal humeral fractures, avulsion of the rotator cuff, and injuries to the adjacent neurovascular structures. The axillary nerve is the most likely to be involved. The diagnosis of glenohumeral dislocation is confirmed with at least two radiographic views of the affected shoulder. A true anteroposterior view usually reveals an anterior dislocation. An axillary lateral view

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provides a more accurate picture of anteroposterior position of the humeral head, and can exclude a posterior dislocation. The shoulder dislocation should be reduced as soon as possible. Many maneuvers have been described, and the clinician should use the method most familiar. Postreduction radiographs can be obtained to confirm realignment. After any reduction procedure, the practitioner should perform a second, well-documented neurovascular examination. Immediate orthopedic consultation is required if reduction is not achieved and for any dislocation associated with fracture. In all cases, the shoulder should be immobilized and appropriate analgesia administered. Orthopedic referral should be obtained even for uncomplicated dislocations. Associated injuries, such as a ligamentous injury, may not be immediately obvious and are difficult to recognize in the acute evaluation. These potential injuries should be re-evaluated at time of follow-up.

Elbow and forearm injuries Elbow dislocation Swelling, deformity, and limited elbow motion suggest significant elbow injury. After the shoulder, the elbow is the second most frequently dislocated major joint [3]. Elbow dislocations are usually the result of a fall on an outstretched hand with the elbow extended. Most are simple dislocations with no concomitant fractures. Complex dislocations are less common, and involve major fractures that require emergency orthopedic consultation. Initial assessment of the dislocated elbow is critical, because it can affect the final outcome. Possible clinical findings include swelling, pain, loss of range of motion, and obvious deformity. Evaluation of other injuries to the ipsilateral upper extremities is necessary. Neurologic and vascular damage with displaced elbow injuries may occur, after which compartment syndrome of the forearm may develop; therefore it is mandatory to assess motor and sensory function of the neurovascular structures of the elbow and forearm. After the assessment, the practitioner must decide whether to reduce the elbow or to splint the joint and send the patient to the emergency department or a consulting orthopedist. This decision should be based on the physician’s experience and comfort with reduction. Radiographs should be examined for occult fractures. Closed reduction of the noncomplicated elbow dislocation is usually possible, but this procedure becomes more difficult if delayed. If the primary care provider attempts reduction, confirmation that the elbow joint has regained full range of motion and stability and a repeat neurovascular examination are essential. Post-reduction radiographs are necessary to confirm reduction. A long arm posterior splint is used to immobilize the elbow at 90 of flexion. Close orthopedic followup is necessary. Any complicated dislocation involving fracture, neurovascular compromise, or open dislocation should be referred immediately.

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Forearm fractures Fractures and dislocations occurring near the elbow and forearm are common in adults and children. These are severe and complex injuries, and frequently require orthopedic referral. These injuries have the potential for deforming complications. In the primary care setting, the initial diagnosis and treatment of these injuries is key to a gratifying recovery and avoiding permanent disability. Most forearm fractures are associated with a history of a fall on an outstretched arm or a direct blow to the forearm. Radial and ulnar fractures cause swelling, tenderness, and deformity of the forearm. Open fractures of this type are common. Isolated ulna or radius fractures cause localized swelling or tenderness over the fracture site. Less deformity is noticed with an isolated radial or ulnar fracture. In evaluating for a fracture, the physician should assess the function of the radial, median, and ulnar nerves, and the extensor and flexor tendons of the forearm. Radiographs of the forearm are needed to confirm the diagnosis. Additional radiographs of the elbow and wrist joints are warranted to rule out any additional injury. Subluxation of the head of the radius Radial head subluxation, or nursemaid’s elbow, is a very common injury in young children. It generally results from a sudden pull on the upper limb, such as that exerted by an adult to prevent a child from falling. The radial head is traumatically subluxed with forceful traction on the hand, with the elbow extended and the forearm pronated. The annular ligament either tears or slips over the radial head, allowing for radial head subluxation. With the release of traction on the arm, the ligament remains interposed between the radial head and the capitellum. The child’s injured elbow will usually be partially flexed and the forearm pronated and supported close to the trunk of the body. There will be anterolateral tenderness over the radial head. Radiographs are typically normal. The physician treats this condition by holding the elbow in one hand with the thumb overlying the head of the radius and slowly flexes the elbowdwhile the forearm is rotated into full supination. The physician may hear a click, signifying reduction, and the child will be quickly comfortable. The child should not be immobilized or restricted in any way. Distal radial fracture A Colles’ fracture, the most common distal radius fracture, is a closed fracture of the distal radial metaphysis. Colles’ fractures are common in adults and rare in children, who tend to fracture through the distal radial physis. The cause of injury is usually a fall on the outstretched hand. Examination of the forearm reveals the classic ‘‘dinner fork’’ deformity of the wrist, which is produced by the dorsal displacement of the fracture. The

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examiner should look for associated injuries, including fracture of the ulnar styloid and median nerve. Nondisplaced fractures can be immobilized in a long arm cast or sugar tong splint and referred to an orthopedist for follow-up. Displaced fractures require prompt referral for reduction, manipulation, and immobilization. Wrist injuries Injuries to the wrist are often misdiagnosed as a sprain. Although wrist sprains are common, that diagnosis should be considered only after careful physical and radiographic examinations have ruled out fracture and dislocation in this anatomic region. An accurate diagnosis of wrist injuries presupposes thorough knowledge of the topographical anatomy of the wrist and a careful, systematic evaluation of the extremity and appropriate radiographs. Ascertaining the specific point of tenderness within the carpus is the most important diagnostic test in assessing injuries to the wrist. Understanding the surface anatomy of the hand and wrist allows the physician to evaluate common injuries and appreciate less common injuries that might otherwise get overlooked. Fractures of the scaphoid result in point tenderness in the anatomic snuffbox and over the scaphoid tuberosity. Scapholunate and lunate injuries are maximally tender just distal to Lister’s tubercle on the dorsum of the wrist. Hamate hook fractures are diagnosed clinically by eliciting tenderness over the area just distal and radial to the pisiform. Scaphoid fracture Fractures of the scaphoid are the most common fracture of the carpal bones [4]. They are also the most commonly missed of all wrist injuries. The fracture is caused by a fall on the outstretched, dorsiflexed hand and wrist. Patients who have pain over the anatomical snuffbox should be treated for a possible scaphoid fracture, and a scaphoid view radiograph should be obtained to assist in the diagnosis. If the patient has scaphoid tenderness without radiographic evidence of a fracture, the wrist should be immobilized in a thumb spica splint/cast and have follow-up radiographs in 10 to 14 days. Orthopedic follow-up is prudent in all cases because: (1) vascular supply is through the bone’s distal portion, and missed diagnosis of a midscaphoid fracture can result in avascular necrosis of the proximal fragment; (2) nonunion is frequent following scaphoid fracture; and (3) there may be related injuries to the forearm, wrist, or hand. Fractures of the hook of the hamate A fractured hook of the hamate is a less common wrist injury that often is not diagnosed, because it is not apparent on standard radiographic views of the wrist. The injury occurs when a patient falls while holding an object, and the object lands between the ground and the ulnar side of the palm, or when

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there is a direct blow to the hypothenar eminence. A delay in diagnosis usually leads to nonunion. Patients will generally have full range of motion and minimal swelling, but will have a decreased grip as compared with the opposite side. The definitive physical diagnostic method is deep palpation to identify the point of maximal tenderness. In addition to standard radiographs of the wrist, a carpel tunnel view should be obtained. The ulnar nerve should also be evaluated during the examination. Patients should be splinted in an ulnar gutter or volar splint and referred to an orthopedist for definitive treatment. Carpal dislocations Scapholunate dislocation is commonly missed in the initial examination. It is the most common form of carpal instability. The mechanism of injury is hyperextension. Patients will complain of pain localized to the scapholunate joint and weakness, especially while gripping. Radiographs demonstrate a space between the scaphoid and lunate that is wider than 3 mm. In the physician’s office, a thumb spica splint is applied, and the patient is referred to an orthopedist for surgical repair. Lunate and perilunate dislocations are the most common carpal bone dislocations. Patients who fall on the heel of the hand are particularly susceptible to these injuries. Common symptoms include wrist deformity and limitation of motion. The deformity may be subtle on an anterior-posterior radiograph. The key to making the diagnosis is a true lateral radiaograph, in which close attention must be paid to the relationship between the radius, lunate, and capitate. In a lunate dislocation, the capitate is aligned with the radius and the lunate dislocates volar to the radius. In a perilunate dislocation, the lunate remains aligned with the radius and the capitate dislocates dorsally relative to the lunate. Perilunate dislocations may occur with or without an associated scaphoid fracture. Patients who have both types of dislocations need to be promptly referred to an orthopedist. Hand injuries Proper evaluation of hand injuries requires simultaneous consideration of the structure and function of all components of the hand. The close structural proximity of nerves, arteries, and bones increases the chances of associated lesions and skeletal injuries of the hand. Treatment cannot be initiated without regard for maintenance of sensibility and mobility of the hand, and the integrity of the skin overlying the injury [5]. Tendon injuries Tendons can be broadly divided into two categoriesdflexor and extensor. Flexor tendon injuries cause less impairment of hand function than extensor tendon injuries. This is mainly because of the redundancy of the hand

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flexor tendons, whereas only one extensor tendon exists for the second through fifth fingers [6]. The challenge for the primary care provider is to recognize the injury and make the proper diagnosis. Initially, the examiner needs to observe the resting posture of the hand. Any change in the normal flexion cascade may be a sign of a tendon injury. Secondly, if a laceration is present, the physician needs to examine the wound with the hand/finger in the position it was in at the time of the injury. Finally, the wound/tendon needs to be examined as the hand/finger is taken through its full range of motion. Flexor tendon injuries Although closed traumatic disruption can occur, these types of tendon injuries most often occur with lacerations. It is imperative to test the function of these tendons throughout their range of motion by evaluating the strength of these tendons against resistance; partial tears will cause weakness against resistance. Many flexor tendon injuries are treated with protective splinting alone. Only an orthopedist or hand specialist should perform surgical repair of flexor tendon injuries. Extensor tendon injuries The mallet finger is a common avulsion injury of the terminal extensor tendon of the distal interphalangeal joint (DIP). This injury occurs when there is an acute, forceful passive flexion of the DIP joint while the joint is in active extension. On examination there is no active extension of the joint. Radiographic examination is important to rule out bony avulsion. Treatments range from simple splinting of the joint in slight hyperextension for 6 to 8 weeks to open reduction and internal fixation. Boutonnie´re deformity results from an injury at the dorsal surface of the proximal interphalangeal (PIP) joint. A sharp force against the tip of a partially extended finger will result in hyperflexion of the middle joint. On examination the clinician should evaluate for point tenderness about the base of the middle phalanx, and for diminished extensor tendon strength with increased pain when the middle joint is extended against resistance. Unfortunately, this injury is often missed and diagnosed as a ‘‘jammed’’ or ‘‘sprained’’ finger. Radiographs should be obtained to evaluate for avulsion fracture. Treatment involves splinting the joint in complete extension. The patient should then be referred to an orthopedic/hand surgeon for possible operative repair. PIP joint dislocations are the most common ligamentous injury of the hand [7]. Fracture-dislocations of the PIP joint occur frequently and are potentially disabling. Hyperextension is the most common cause. The usual deformity is dorsal displacement of the middle phalanx on the proximal phalanx. After a careful history and examination for swelling, neurovascular

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status, and range of motion, a true lateral and posteroanterior radiograph should be obtained. The radiograph will demonstrate any joint displacement, angulation, and incongruity. Dorsal and lateral reduced injuries should be splinted at 30 of flexion following reduction and referred. The definitive treatment of PIP joint injuries depends on the type of injury. Hand fractures General principles of orthopedic management apply to fractures of the hand. Most closed phalanx fractures can be stabilized with splinting and managed on an outpatient basis. Open, intra-articular, or unstable phalanx fractures require more immediate consultation with a specialist. Metacarpal fractures of the head, neck, shaft, or base should be referred promptly for emergency room or orthopedic evaluation because of the difficulty with reduction, rotational deformity, and angulation that is common in these types of fractures. Phalangeal fractures Proximal phalangeal injuries can result in significant functional disability if not recognized and treated appropriately. Injuries to the fingers are usually a result of direct trauma to the digit. After a detailed history and physical examination, the possible presence of a rotational deformity must be carefully considered. Often the oblique radiograph does not show the true nature of the fracture, and a true lateral radiograph is needed to show angulation of the fracture. Stable, nondisplaced middle and proximal phalangeal fractures without angulation or rotational deformity can be managed with dynamic splinting to the adjacent finger. Follow-up radiographs should be obtained in 7 to 14 days to assess angulation and healing. Unstable fractures of the proximal and middle phalanges and displaced intra-articular fractures generally require operative reduction and fixation. Metacarpal fractures Metacarpal neck fractures are very common, particularly neck fractures of the fourth and fifth metacarpals (boxer’s fracture). They are usually the result of a direct blow or crush injury to the metacarpal. Radiographs demonstrate the proximal fragment angulating in the dorsal direction, whereas the distal fragment angulates in the volar direction. The amount of angulation that is acceptable varies directly with the normal physiologic mobility of the involved metacarpal. Rotational deformities, if present, must be completely corrected. Having the patient slowly make a fist with the palm facing upward can help assess for rotational deformities. Each digit should point toward the scaphoid tuberosity and should not overlap. Reduction of these types of fractures is usually beyond the scope of most primary care physicians. The patient should be splinted in a volar or gutter splint, depending

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on the injured metacarpal, and referred to an orthopedic surgeon. Most of these metacarpal neck fractures can be treated with closed reduction and casting.

Acute lower back pain Acute low back pain is one of the most common symptom-related complaints for visits to primary care physicians. A majority of these patients first present to a primary care physician, not a subspecialist. Though back pain has a benign course in over 90% of patients, the primary care physician must be vigilant and comfortable identifying the few patients with warning signs of a neurologically impairing or life-threatening etiology. The goal of the office assessment of patients with acute lower back pain is to evaluate for potentially dangerous etiologies first, which, if not promptly recognized, could result in significant morbidity and mortality. The approach recommended by these authors and others is to obtain from all patients who have lower back pain a systematic history, and to perform a careful physical examination and rely on the presence of so-called ‘‘red flags’’ or ‘‘alarm symptoms’’ to guide further diagnostic tests, specialty evaluation, and treatment. A summary of the red flag signs and symptoms can be found in Box 1. A careful and comprehensive history and physical examination are used to

Box 1. History and physical examination red flags Signs and symptoms concerning for infection or malignancy Age under 18 or over 50 Pain lasting for more than 6 weeks History of cancer Fever, chills, night sweats, weight loss Unremitting pain, night pain (may awaken patient from sleep) Intravenous drug users, immunocompromised Fever Signs and symptoms concerning for epidural compression Bowel or bladder incontinence Saddle anesthesia Decreased or loss of anal sphincter tone Severe or progressive neurologic defect Motor weakness Signs and symptoms concerning for fracture Major trauma Minor trauma in the elderly

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identify the small percentage of patients who have serious pathology as the underlying cause of their back pain. This approach can also be used to differentiate the most common entity, benign nonspecific back pain, from syndromes that require more immediate identification and evaluation: (1) nerve root compression, which refers to pain with accompanying sensory and motor deficits in the distribution of a lumbosacral nerve root; and (2) epidural compression syndrome, which consists of cauda equina syndrome, the closely related conus medullaris syndrome, and spinal cord compression. These disorders are grouped because they share a similar presentation and initial evaluation. Different causes of acute low back pain tend to have different distinguishing characteristics. For example, peripheral nerve pain may be described as ‘‘pins and needles’’ or ‘‘burning,’’ as opposed to nerve root pain, which is transient and very sharp, relieved with recumbent positioning and exacerbated by Valsalva-type maneuvers. Discogenic pain is typically worse with flexion, whereas pain from spondylolisthesis is aggravated by facet loading, which occurs in extension. Spinal stenosis is characterized by lower extremity radicular pain, which also becomes worse with extension (standing) and improves with flexion (sitting). Typical nonspecific back pain is unilateral. It may radiate to the buttocks or posterior thigh but not past the knee. Pain is increased with movement, improved with rest, and there are no complaints of numbness, weakness, or bowel or bladder dysfunction. Sciatica is sharp and burning, and radiates posteriorly down the leg past the knee. There may also be associated numbness or weakness. Epidural compression syndrome is associated with numbness, weakness, bilateral leg pain, incontinence, and saddle anesthesia. The importance of the clinical history cannot be overemphasized. As with any patient who complains of pain, symptoms should be characterized by the basic historical elements of the episode, such as the onset, character, severity, location, exacerbating, and alleviating factors, and the presence of radiation. Further questions, related to the aforementioned red flags, must also be asked to identify high-risk patients. Physicians must be especially cautious if the patient is under age 18 or over age 50, because tumors and infection appear with higher frequency in these age groups. In the older patient, one must always consider an abdominal aortic aneurysm (AAA) as a potential etiology of back pain. The presence of hematuria can make this entity appear as the classic kidney stone. The elderly may sustain fractures, including pathologic fractures, with relatively minor trauma. In other patients, any history of moderate to major trauma should increase suspicion of fracture. The immunocompromised and intravenous drug users are at increased risk of spinal bacterial infections. In fact, any patient who has intravenous drug use and back pain should be assumed to have an abscess or osteomyelitis until proven otherwise. Those who have a past medical history of cancer, especially cancers that are known to metastasize to the spine, are also at high risk. Most episodes of lower back pain will resolve within 4 to

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6 weeks. Lack of significant improvement in 6 to 8 weeks, or pain of greater duration are other red flags [8,9]. It should then be determined whether the patient is primarily describing back or leg symptoms. Radicular pain in a dermatomal distribution, often into the lower hamstring, knee, and foot, indicates nerve root compression or irritation (sciatica), whereas the more common nonspecific back pain without dermatomal radiculopathy implies muscle or ligamentous strain. The clinician should attempt to elicit historical features that are suggestive of infection or malignancy, such as unintentional weight loss, fevers, chills, dysuria, and night sweats. These screening questions are very important, because a majority of patients whose back pain is found to be caused by spinal malignancy have no known history of cancer. Because most benign back pain is tolerable, worsened with activity, and improved with rest, symptoms such as night pain and severe unrelenting pain that is not relieved by rest and recumbency should also raise a red flag. Symptoms that are suggestive of epidural compression syndrome are mainly neurologic in origin, and include any loss of bowel or bladder function, urinary retention, saddle anesthesia, or distal leg numbness or weakness. Pain that is worsened by coughing, sneezing, prolonged sitting and standing, or Valsalva maneuvers raises suspicion of disc herniation. The purpose of the physical examination is to evaluate neurologic complaints discovered in the history, to identify potential additional neurologic defects, and to continue to uncover any red flags. The neurologic examination systematically tests the reflexes and the motor and sensory components of the most commonly affected nerve roots. The clinician must account for abnormal or unstable vital signs, which may indicate an extraspinal cause of the back pain such as an AAA. The presence of fever (infection) and focal vertebral tenderness to percussion (fracture, infection) are important findings. Digital rectal examination should be performed in anyone in whom epidural compression syndrome is being considered (severe pain, hard neurologic findings) to assess sphincter tone and perianal sensation, to check for masses, and for a possible perirectal abscess. The straight leg raise (SLR), which tests for the presence of a herniated disc causing nerve root compression, is one of the most important tests for evaluating back pain (Appendix). Pain referred to the affected leg when the opposite leg is tested, called a positive crossed straight leg raise, is highly indicative of nerve root irritation and has a very high specificity. Reproduction of pain in the back, hamstring, or buttock region does not constitute a positive test. The clinician must also be able to distinguish between nonorganic back pain and true back pathology. Waddell’s signs are physical examination findings that can aid in making this important distinction [10]. Superficial, nonanatomic, or variable tenderness and gross overreaction during the physical examination suggest a nonorganic cause. The clinician may also simulate back pain through provocative maneuvers such as axial loading of the head or passive rotation of the shoulders and

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pelvis. Neither maneuver should elicit low back pain. There may be a discrepancy between the supine and sitting SLR. The seated version of the test, sometimes termed the distracted SLR, can be performed while distracting the patient or appearing to focus on the knee. Further, radicular pain elicited at a leg elevation of less than 30 is suspicious because the nerve root and surrounding dura do not move in the neural foramen until an elevation of more than 30 is reached. Sensory and motor findings suggestive of a nonorganic cause include nondermatomal sensory loss or cogwheel or give-way weakness. Waddell’s signs, especially if three or more are present, correlate with malingering and functional complaints. These signs can be used to evaluate select patients, and are merely a component of a comprehensive physical examination. They should never be used independently because they lack the sensitivity and specificity to rule out true organic pathology. A detailed distal neurologic examination must be performed that targets the three most common locations for disc herniation: L4, L5, and S1. Over 95% of herniated discs affect the L4-L5 or L5-S1 interspaces [11,12]. Those who have pathology at the higher lumbar spine will have hip flexion weakness and anterior thigh sensory changes in the corresponding dermatome. Those with pathology at the lower sacral levels (S2-S5) can have abnormal perianal sensation, anal wink (S2-S4), rectal tone (S2-S5), and bladder function. An understanding of the key physical examination components of the targeted L4-S1 neurologic examination is essential (Table 1). Though unnecessary for office practice, urinary catherization can be helpful in evaluating select patients. Measurement of a postvoid residual volume tests for the presence of urinary retention with overflow incontinence, suggesting compromised neurologic function. This is a very sensitive and specific finding for cauda equina syndrome. Laboratory testing, consisting of a complete blood count (CBC), erythrocyte sedimentation rate (ESR), and urinalysis (UA), is indicated in cases in which infection or tumor is suspected. Blood cultures, prostate-specific antigen (PSA), C-reactive protein (CRP), calcium and alkaline phosphatase may also be considered in appropriate cases. The emergency or specialty physician who will be assuming care of the patient should order the appropriate diagnostic imaging. Plain films (anteroposterior [AP] and lateral) are often the first step in cases of suspected infection, fracture, malignancy, or neurologic compromise. Additional views are only indicated if spondylolysis Table 1 L4-S1 neurologic examination (wf) Neurologic level

Motor

Sensory

Reflex

L4 L5

Knee extension Heel walking Great toe dorsiflexion Toe walking Foot eversion

Anteromedial thigh/knee Great toe web space

Patellar None

Lateral foot

Achilles

S1

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or spodylolisthesis, problems common in children, are suspected,. A bone scan is useful when looking for spinal stress fractures and spinal metastatic disease. Computed tomography scan is the study of choice for vertebral fractures and other bony disease. CT with myelography may be used in those patients who are unable to have magnetic resonance imaging. With the exception of the acute traumatic evaluation, MRI is the most informative investigative modality. An MRI is the modality of choice for evaluation of spinal infectious lesions, malignancy, herniated discs, and epidural compression syndrome. Disc disease is a very nonspecific finding, and also a component of normal aging. In fact, one in four of all asymptomatic persons younger than 60 will have positive MRI findings of a herniated disc. That number jumps to one in three in people over the age of 60. In one study, over 50% of patients studied were identified as having a disc bulge [13]. Most patients with back pain have the classic nonspecific lumbosacral back pain that may radiate into the buttocks or thigh, and that is worsened with activity and relieved with rest. Examination does not reveal any red flags or neurologic abnormalities. These patients are managed conservatively, which may include ice, heat, prescribed analgesia, or muscle relaxants, as well as close follow-up to ensure that the episode resolves. These types of patients should be told to continue daily activities as tolerated and should not be prescribed bed rest. Sciatica is defined as radicular pain into the leg in the distribution of a lumbar or sacral nerve root, which is often accompanied by a motor or sensory deficit. This is the classic clinical scenario of a herniated disc, which occurs when the tough outer disc layerdthe annulus fibrosisdtears, and the inner gelatinous materialdthe nucleus pulposusdprolapses, inflames, and presses on a nerve root. Patients complain less of back pain and more of lower extremity pain and radicular symptoms, because of the anatomic distribution of the nerve roots involved. Diagnosis consists of localizing the pain and neurologic dysfunction to an isolated nerve root. Multi-nerve– root pathology is a potential indicator of a spinal mass lesion or central disc herniation. A positive straight leg test further supports the diagnosis. Patients who have an otherwise normal examination and no hard neurologic findings do not require an urgent MRI or subspecialty referral. In fact, many patients who have a herniated disc can be managed by their primary care physician without specialty referral. Surgery is unlikely ever to be considered until a patient has failed a period of conservative therapy. Only epidural compression syndromes require emergent spinal decompression surgery. Epidural compression syndrome is characterized by lower back pain, unilateral or bilateral sciatica, lower extremity sensory or motor deficits, decreased or asymmetric deep tendon reflexes, and bowel or bladder dysfunction. Causes are multiple and include midline disc herniation, trauma, or mass effect from an abscess, hematoma, or spine metastases. These lesions are a surgical emergency and require immediate diagnosis and treatment. In

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cauda equina syndrome, urinary retention with overflow incontinence (greater than 50–100 mL) is the most common finding. Sensory loss, commonly in the buttocks or perineal region (saddle anesthesia), is the most common sensory deficit. Anal sphincter tone is often decreased. These patients require immediate specialty evaluation, MRI, and steroid administration to minimize the ongoing neurologic damage from compression and edema. Studies have shown that the ultimate functional outcome is largely dependent on the duration of symptoms and the condition at the time of presentation. Patients who receive rapid surgical decompression have a good prognosis. Spinal infections are an uncommon though emergent cause of back pain. Infection can affect the disc space or the vertebral body, or form an epidural abscess. Infection occurs via hematogenous spread, skin and soft-tissue infection, and following spinal surgery or epidural anesthesia. Spinal abscess of unknown etiology is not uncommon. Predisposing factors for epidural abscess are immunocompromised states such as intravenous drug abuse, diabetes mellitus, chronic renal failure, and alcoholism. Patients who have spinal infections often do not present acutely, because prolonged symptoms are common. Multiple visits to physicians often precede the correct diagnosis. Patients are often misdiagnosed as having a musculoskeletal strain. The key to diagnosis is not overlooking the disease as a possible cause. Outcome is related to the speed of diagnosis, and that diagnosis is made before the development of myelopathic signs. Missed diagnosis carries serious potential morbidity and mortality. Patients present with back pain, fever, chills, weight loss, unrelenting pain, and eventual neurologic deficits. Spinal cord damage occurs because of direct compression, local venous thrombosis, and interruption of the arterial supply. Focal neurologic deficits are late findings. Patients require MRI with contrast and immediate evaluation by a spine surgeon. Another infrequent though emergent etiology of back pain is spinal malignancy. Pain is the initial symptom in a vast majority of these cases. Those who have new or progressive neurologic signs or symptoms (weakness, sensory changes, decreased or absent reflexes, and so forth) should have emergent specialty evaluation and imaging with MRI. Unlike cauda equina syndrome, which requires only a focal MRI of the lumbosacral spine, suspicion of malignancy requires a screening MRI of the entire spine to evaluate for falsely localizing lesions, because there is a 10% risk of distant asymptomatic metastases, which may affect treatment. A metastatic workup, including CT of the chest, abdomen, and pelvis, should be obtained to identify the primary malignancy. Spinal cord compression secondary to neoplasm will also require consultation for possible emergent radiation therapy. Cancers known to cause spinal malignancies include primary cancers, myeloma, and metastatic cancers (breast, lung, thyroid, kidney, prostate). Metastatic disease is far more frequent than primary bone tumors. Unlike adults, children are more likely to have an established diagnosis of their back pain. Etiologies such as infection, including discitis and

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osteomyelitis, and tumor must be considered. Also common in preadolescent and adolescent children is spondylolysis, a defect in the pars interarticularis often secondary to repeated lumbar stress. It affects young athletes such as football players and gymnasts. Unlike nonspecific muscle pain, pain is exacerbated by spine extension (facet loading) and improved with flexion. The defect of the pars may be seen on oblique radiographs. Spondylolisthesis is the slippage of one vertebra anteriorly in relation to the vertebral body below it, and is best visualized on the lateral spine radiograph. The proper clinic disposition of patients with lower back pain is very important. Most patients will leave the office with a diagnosis of nonspecific back pain, and the problem will resolve spontaneously. Those with sciatica and no acute neurologic deterioration can be managed conservatively. Though the acute pain is often debilitating, pain often abates with nonsteroidal anti-inflammatory drugs (NSAIDs), analgesics, and physical therapy. MRI can be delayed for approximately 4 to 6 weeks. Those who have a herniated disc with symptoms in a single nerve root distribution can be managed conservatively as outpatients and re-evaluated in 1 week. Patients with multiroot or bilateral neurologic findings, or signs and symptoms of malignancy or infection should be sent to an emergency department that is equipped to perform the appropriate imaging study, most likely an MRI, and which has access to specialty consultation. Unless there is concern for acute decompensation en route to the emergency department, patients may be transported from the office via ambulance with basic life support (BLS) trained personnel. Patients who have back pain and a past medical history of cancer are a unique group. Those with isolated back pain without neurologic findings suggestive of cord compression can be closely followed for improvement and lack of progression, and should be re-examined within 5 to 7 days. All back pain patients evaluated in the primary care doctor’s office should be given clear ‘‘discharge’’ instructions, with unambiguous indications to return or go to the nearest emergency department with symptoms such as new or progressive leg weakness, bowel or bladder dysfunction, or saddle anesthesia. When sufficient concern exists for one of the red flag diagnoses, the patient’s workup should be transitioned to the local emergency department. The clinical pitfall to avoid is diagnosing an emergent back pain episode as ‘‘just a back strain.’’ The clinician should check for the presence of red flags in all patients who have back pain. To summarize, the patients who have low back pain emergencies are: (1) those who have a past medical history of malignancy and new back pain with neurologic findings, (2) those who have back pain and symptoms of epidural compression syndrome, (3) those who have back pain with symptoms suggesting an infectious etiology, (4) those who have back pain with gross muscle weakness or paralysis, and (5) those who have back pain and multiple nerve root involvement correlating with the clinical examination.

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Foot and ankle injury Patients with injuries to the foot and ankle are common in both physician’s offices and outpatient clinics. The common clinical question arises as to which patients need plain films of their foot or ankle. Clinical decision guidelines called the Ottawa Ankle Rules were developed to help the physician determine whether to obtain radiographs of the midfoot or ankle (Box 2). The rules were derived from an initial series of studies that were later prospectively validated. These rules have been reported to have a sensitivity of 97% to 100% [14]. All office patients presenting with a recent ankle injury should be sent for imaging if they meet the Ottawa ankle criteria. Ankle sprains are some of the most frequent sports-related orthopedic injuries. Common orthopedic injuries may mask themselves as simple ankle sprains, delaying both accurate diagnosis and appropriate treatment, and at times causing a worse long-term prognosis. An Achilles tendon injury can be easily overlooked unless it is specifically considered. This condition has been misdiagnosed in as many as 25% of cases [15,16]. The Achilles tendon represents the distal confluence of the gastrocnemius and soleus muscles, which insert on the calcaneus. The typical patient is a middle-aged male, poorly conditioned or sedentary, or a ‘‘weekend’’ athlete. The usual mechanism of injury is sudden or unexpected dorsiflexion of the foot or ankle. Disruption usually occurs 2 to 6 cm proximal to the tendon insertion, corresponding to an area of poor vascular supply. A common false assumption is that plantar flexion at the ankle is controlled solely by the Achilles tendon. In fact, many muscles can cause plantar flexion, including the toe

Box 2. Ottawa ankle and foot rules An ankle radiograph series is only required if there is any pain in the malleolar zone and any of these findings:  Bone tenderness at the posterior edge of the distal 6 cm or tip of the fibula  Bone tenderness at the posterior edge of the distal 6 cm or tip of the tibia  Total inability to bear weight, both immediately and in the office (weight-bearing is defined as the ability to take four steps regardless of limping) A foot radiograph series is only required if there is any pain in the midfoot zone and any of these findings:  Bone tenderness at the base of the fifth metatarsal  Bone tenderness at the navicular  Total inability to bear weight, both immediately and in the office

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flexors (flexor digitorum and flexor hallucis longus), tibialis posterior, and the peroneal muscles. Factors predisposing a person to rupture of the Achilles tendon include certain systemic inflammatory diseases, fluoroquinolone antibiotics, prior tendon steroid injections, and Achilles tendonitis. The diagnosis of Achilles tendon rupture is primarily clinical. Patients may report a ‘‘pop’’ or ‘‘snap’’ at the time of injury associated with sudden severe pain, similar to a ‘‘gunshot wound.’’ The acute pain may resolve quickly, and the episode may be misdiagnosed as an ankle sprain. The clinician may note swelling of the lower calf. There may be a palpable defect in the tendon 2 to 6 cm proximal to its insertion, called a positive ‘‘gap sign,’’ though this may be missed if swelling is significant. Patients may still be able to plantar flex the foot, albeit weakly, as described above. The patient often has difficulty bearing weight. The test to diagnose a complete rupture of the Achilles tendon is called the Thompson test (see Appendix). Imaging is unnecessary in cases of obvious tendon rupture. MRI or ultrasound are the diagnostic modalities of choice if the clinical diagnosis is in doubt. Office treatment following diagnosis involves rest, ice, compression and elevation (RICE). In addition, the clinician should provide crutches and pain-free immobilization in a posterior splint in passive equines position (plantar flexion). Patients may be sent home and should be referred for orthopedic follow-up within 72 hours. Prolonged delay may result in retraction of the tendon. Both operative and nonoperative treatment options are available, and depend on individual patient characteristics. The patient’s age, level of activity, degree of tendon retraction, and general medical health guide definitive care. Conservative treatment involves cast immobilization in plantar flexion, so as to approximate the two ends of the torn tendon. Surgical repair decreases the incidence of rerupture and allows an earlier return to activities [17]. The Maisonneuve fracture complex is defined as a fracture of the proximal third of the fibula, with associated syndesmosis disruption and deltoid ligament tear or medial malleolar fracture. Although less common than other types of ankle fractures, the Maisonneuve fracture is often initially misdiagnosed, which may result in long-term disability. The patient may present with pain in the region of the ankle without pain in the proximal fibula. This fracture will be missed if the clinician concentrates solely on the injured ankle and does not examine the proximal fibula. The latter is very important. Unless the diagnosis is considered at the time of the examination, only ankle films will be ordered, and the fracture will be missed. The mechanism is a pivot stress to the ankle, with external foot rotation in which the force vector travels upward, damaging the syndesmosis complex and fracturing the proximal fibula. This diagnosis should be suspected in patients who have a history of ankle eversion, together with medial malleolar and proximal fibular tenderness on examination. These patients require ankle and lower extremity plain films. The proper diagnosis will not be missed if the proximal fibula is palpated in all patients who have an ankle sprain.

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Patients should be referred to an orthopedist for open reduction and internal fixation. The base of the fifth metatarsal is a common site of fracture. Both the Jones’ fracture and the pseudo-Jones’ fracture involve pain over the fifth metatarsal base. These two entities should be managed very differently. They have different prognoses that must be distinguished by the primary care physician. A Jones’ fracture is a transverse fracture of the proximal diaphysis of the fifth metatarsal. It may be incorrectly diagnosed, unless the base of the fifth metatarsal is palpated for tenderness in all patients with ‘‘ankle sprains.’’ A true Jones’ fracture occurs approximately 1.5 cm distal to the base of the fifth metatarsal (the junction of the diaphysis and metaphysis). This must be differentiated from the more common pseudo-Jones’ fracture, in which the peroneal brevis tendon avulses its osseous attachment at the base of the fifth metatarsal. The avulsion fracture is associated with an inversion injury mechanism, as opposed to the Jones’ fracture, in which a strong adduction force is applied to the forefoot with the ankle plantarflexed. The difference is easily visible on plain films. A common clinical error is that only ankle films are ordered, which may not include or provide clear visualization of the fifth metatarsal. Proper clinical examination of the patient should always include palpation of the fifth metatarsal and, if it is tender, a foot imaging series should be ordered. Patients who have a Jones’ fracture should be made non-weight–bearing with crutches, and immobilized in a posterior splint. They should be referred to an orthopedist within 24 to 48 hours, who will place them in a non-weight–bearing, short leg cast for approximately 6 weeks and follow them closely. Competitive athletes or other highly active individuals may be offered surgery. Because this area is the weight-bearing lateral margin of the foot and since it corresponds to a watershed area of the blood supply, fracture is frequently complicated by nonunion, malunion, or recurrence. These complications occur in almost one fourth of patients treated conservatively [18]. Avulsion fractures can be treated with a hard-sole shoe, walking cast, or compression wrap. Patients should be made weight bearing as tolerated, and will usually heal well without sequelae. The clinical pitfall is misdiagnosing a potentially serious lower extremity injury as ‘‘just an ankle sprain.’’ The clinician should check all patients for other injuries in a systematic manner. Specific injuries not to be missed include Achilles tendon rupture, proximal fibular fracture, and fifth metatarsal fractures. Knee injuries Knee injuries are among the most common musculoskeletal disorders. The primary care physician is frequently called on to evaluate patients with acute bony and soft-tissue knee injuries. Being knowledgeable about and comfortable with evaluating knee injuries is an invaluable part of

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a physician’s clinical armamentarium. Clinical decision guidelines similar to those used for the ankle exist to aid in the determination of whether knee radiographs are necessary. Although not as widely used as the Ottawa ankle rules, two popular decision rules exist: the Ottawa and Pittsburgh knee rules (Box 3). Both rules have a high sensitivity (97%–99%), but the Pittsburgh knee rules have greater specificity [19]. The standard imaging series consists of three views: AP, lateral, and oblique radiographs. A sunrise view should be included to detect nondisplaced vertical patella fractures that may be missed in the conventional three-view series. Rupture of the quadriceps tendon results from forceful contraction of the quadriceps muscle, or can be secondary to a fall on a flexed knee. This injury is most often seen in older patients and younger individuals involved in jumping activities such as high jump or basketball. Rupture occurs just proximal to the patella. Just as in rupture of the Achilles tendon, patients will report severe pain, a loud ‘‘pop,’’ and an immediate inability to bear weight or extend the knee. Examination often reveals a palpable soft-tissue defect proximal to the superior pole of the patella. This may be obscured if sufficient edema has already developed by the time of examination. Patients will be unable to perform a seated straight leg raise, or to extend the knee from a fully flexed position. Knee films should be obtained to rule out associated fracture. Patients should be placed in a knee immobilizer and provided crutches. Early diagnosis and surgical repair within 48 to 72 hours are necessary to preserve the extensor mechanism of the knee. Two commonly confused musculoskeletal disorders warrant discussion because of their varied management and treatment: patellar dislocation and knee dislocation. Both disorders may have spontaneously reduced before evaluation, thereby increasing the potential for missed diagnosis. A

Box 3. Ottawa and Pittsburgh knee rules Ottawa knee rules. A knee radiograph series is required for acute knee injuries and any of these following conditions:  Age over 55  Fibular head tenderness  Inability to flex to 90  Inability to bear weight for four steps both immediately and in the office Pittsburgh knee rules. A knee radiograph series is only required if there is blunt trauma or a fall as mechanism, plus either of the following conditions:  Age under 12 or over 50  Inability to bear weight for four steps both immediately and in the office

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true knee dislocation is an orthopedic emergency. It is a rare injury because of the strength of the supporting ligaments. Knee dislocations usually require a great amount of force, such as would be generated by motor vehicle accidents, falls, or sports injuries. Dislocations with relatively minor trauma have been reported, often in obese patients. Anterior and posterior dislocations, named by the direction of the displacement of the tibia relative to the femur, are most common. Dislocations involve disruption of at least two of the major knee ligaments with the anterior and posterior cruciate ligaments (ACL, PCL) being most frequently involved. These injuries are typically associated with a large hemarthrosis. Because of the potentially devastating and limb-threatening vascular consequences, all office physicians need to be aware of the presentation, diagnosis, and management of knee dislocations. The nature of the injury is not always clinically evident because of spontaneous reduction at the time of evaluation. Further, swelling may be negligible because of tearing of the capsular structures and resulting dissipation of the acute hemarthrosis into the adjacent soft tissue. Therefore, a significant mechanism of injury in the setting of a multidirectional, severely unstable knee may indicate a spontaneously reduced dislocation. In any suspected case, a thorough neurovascular examination must be performed before and after reduction. Up to one third of injuries involve the tightly tethered, popliteal artery. Though the absence of distal pulses suggests vascular injury, the presence of pulses cannot be used as evidence of the lack of a vascular injury. Also, as many as 20% to 30% of cases involve injury to the common peroneal nerve, which controls ankle dorsiflexion and sensation over the first dorsal web space [20]. In a small study of knee dislocations [21], two thirds were reduced on presentation. The distribution of ligamentous injuries favored ACL (84%), PCL (87%), and combination (71%) injuries over injuries to the medial collateral (44%) and lateral collateral (62%) ligaments. Especially in cases of vascular compromise, knee dislocations should be reduced using longitudinal traction as soon as possible. The patient should then be placed in a long posterior splint in 15 of flexion and immediately sent to the nearest hospital for further evaluation. Whereas in the past all patients received arteriography, today a selective approach is employed. All patients showing hard signs of a vascular injury, such as an absence of pulses or presence of a bruit, require arteriography. Note that such hard signs may not manifest until after 24 to 48 hours. Patients with a normal vascular examination and ankle-brachial index may be admitted overnight for serial neurovascular examinations. Patella dislocations are relatively benign compared to knee dislocations. The usual mechanism of injury is a twisting movement about the knee. Direct trauma to the knee can also cause dislocation. Patellar dislocations are more common in women, because of their greater physiologic laxity, and in those who have connective tissue disorders. Dislocations predominately dislocate laterally and have a high rate of recurrence. The trauma results in a tearing of the medial patellofemoral ligament and the patella being

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displaced over the lateral condyle. The resulting pain, hemarthrosis, inability to extend the knee, and obvious deformity are very troubling to the patient. The patella may spontaneously reduce in the field with simple leg straightening. Otherwise, acute dislocation of the patella is usually obvious on clinical evaluation, because the dislocated patella causes a large bulge in the lateral leg with a prominent medial femoral condyle. If the dislocation is recent and did not spontaneously reduce, immediate reduction should be attempted. Reduction is moderately uncomfortable and may occasionally require procedural sedation. The patient should be placed in the supine position with the hip flexed (to relax the quadriceps muscles). The knee is then slowly hyperextended while gentle medial pressure is applied to the lateral aspect of the dislocated patella. Successful reduction is indicated by the return of the patella to the trochlear groove, absence of deformity, and normal knee function. Knee radiographs should be obtained after the reduction to assess for avulsion or fracture. Following reduction, the patient should receive crutches, be placed in a knee immobilizer in locked extension, and should follow the RICE protocol. The patient may be made partially weight-bearing as tolerated, and later be advanced to full weightbearing. Patients should return for follow-up in 1 week with either their primary care physician or an orthopedic surgeon. They will benefit from improving their range of motion and strengthening the quadriceps, and may be given a referral for physical therapy. Severe dislocations with associated ligamentous injury in competitive athletes and anyone who has a recurrent dislocation may benefit from orthopedic referral. Most athletes should wear a supportive knee brace and can expect to return to play within 4 to 6 weeks. Although the majority of knee injuries that present to the primary care physician are overuse injuries, acute traumatic soft tissue injuries of the knee are very common. Soft-tissue injuries of the knee are better classified as urgencies than emergencies. It is more important for the primary care physician to identify the presence of an internal knee derangement than to identify the specific injured structure. Another important category of patient presentation is the patient with acute knee trauma, hemarthrosis and a negative radiograph series. These patients are likely to have one of the following three entities: (1) an acute ligamentous tear, (2) a meniscal tear, or (3) an osteochondral fracture. Obtaining a detailed history and a careful physical examination can help distinguish among these conditions. The specific mechanism of injury (eg, a football player having been tackled from the side) is one of the most important aspects of the history. The physician should inquire about the direction and degree of the traumatic stress and the position of the knee at the time of injury. Also relevant is whether there was an audible ‘‘pop’’ at the time of injury, if there was immediate or delayed swelling, if the patient can continue to ambulate, and whether the knee locks or ‘‘gives way.’’ Always consider that pain referred from the hip or back may present as knee pain. Because of the ACL’s rich blood supply, sudden onset of a large effusion suggests an ACL injury.

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The physical examination is relatively straightforward, and includes inspection for deformity, edema, ecchymosis, and erythema. The examination can be limited in patients with severe pain or those with a large, tense effusion. The physician should always palpate for bony tenderness and order plain films if appropriate. The knee should not be significantly stressed if a fracture is suspected. The physician must assess neurovascular stability and rule out associated injuries. If radiographs are negative or not indicated, assessment of the anterioposterior and varus-valgus stability of the knee is the next step. A review of the physical examination of the knee can be found in the Appendix. Ligamentous injuries are classified according to a threelevel grading system. A Grade I sprain involves tenderness, mild, if any swelling, and no joint laxity. Grade II injuries involve a partial ligament tear with some laxity of the joint. Grade III injuries are complete ligamentous tears without a firm end point during stress testing. Important points to consider include always examining the uninjured knee first to establish a baseline clinical stability and dispel the patient’s fears, thereby improving cooperation. One must compare any irregularities to the uninjured knee, because abnormalities may be subtle. Side-to-side differences are more important than absolute laxity. The physician should consider aspirating large, tense joint effusions to increase the patient’s comfort, aid in diagnosis, and to improve the accuracy of the physical examination. There is a significant risk of a false-negative Lachman test in the presence of a large effusion. If the aspiration of a hemarthrosis reveals fat globules (lipohemarthrosis), a fracture is likely. The cruciate ligaments, the ACL and PCL, are primary stabilizers of the knee, and resist anteriorly and posteriorly directed stress, respectively. The ACL is a very frequently injured major knee ligament. It is often injured in contact sports, skiing, basketball, and soccer. The mechanisms of injury include acute extreme deceleration, noncontact- and contact-related hyperextension or valgus force, and external rotation. Patients typically report the knee ‘‘giving way,’’ with associated sudden pain, an audible ‘‘pop,’’ immediate swelling (hemarthrosis usually develops within 2 hours of injury), and an inability to continue activities. Diagnostic tests include the anterior drawer, Lachman, and pivot shift tests. The Lachman test is the single best component of the physical examination for testing the integrity of the ACL, and is more sensitive and accurate than the anterior drawer test. Meniscal tears frequently accompany, ACL tears. Definitive treatment of an ACL injury depends on the patient’s age, desired activity level, and whether there are other associated injuries. The ACL requires elective surgical repair for anyone planning return to sports activities. The PCL, by comparison, is broader and stronger than the ACL, and is less frequently injured. Injury is most frequently caused by a direct blow to the proximal tibia (classically, a knee-against-dashboard injury in a motor vehicle accident) or a fall on a flexed knee with a plantar-flexed foot. Hyperextension, a varus/valgus directed force while in full extension, and

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hyperflexion are less common mechanisms of injury. PCL injuries require an increased amount of force, and though isolated injuries do occur, PCL injuries are often part of a combined ligamentous injury. Unlike the ACL injury, PCL injury does not usually involve a distinct pop or tear. Patients often report only vague symptoms, such as gait unsteadiness, and they usually do not have severe pain. Swelling, if present, is often mild. Isolated injuries are often missed on initial evaluation. The posterior drawer test is diagnostic. Treatment of isolated Grade I and II PCL injuries is conservative. Grade III injuries, combined injuries, avulsion fractures, and failure of nonsurgical treatment (ie, recurrent symptomatic instability) often require surgical reconstruction. The medial collateral ligament (MCL) and the lateral collateral ligament (LCL) are the medial and lateral stabilizers of the knee and resist valgus and varus stress, respectively. The MCL is more frequently injured than the LCL. The cause of injury to the MCL is usually a lateral blow to the knee with the foot in a fixed position, or a valgus-directed force to the knee with external tibial rotation. LCL injuries are caused by varus directed stress with internal tibial rotation. Isolated LCL injuries are relatively rare. Varus and valgus stress tests examine the integrity of the collateral ligaments. The degree of injury can be estimated by the amount of joint line opening. The ligaments may also be tender to palpation along their entire course. With the possible exception of complete LCL tears, isolated tears usually heal without surgical intervention, with the possible exception of complete LCL tears. If the physician discovers a high-grade injury to the posterior or lateral side of the knee, referral for orthopedics is always prudent because of the need to rule out a commonly missed entity called a posterolateral corner injury. The posterolateral corner is a complex anatomical region that contributes to the static and dynamic stability of the knee. It is comprised of the LCL, popliteus muscle and tendon, the popliteofibular ligament, the arcuate ligament, and the posterolateral capsule. Posterolateral corner injuries are associated with posterolateral knee pain, tenderness, and swelling. As the acute swelling subsides, the patient may notice instability of the extended knee. Accurate diagnosis is important because this injury may require early surgical intervention for a satisfactory result. The menisci are fibrocartilaginous pads positioned on the articulating surface of the tibia. The blood supply enters from the periphery and does not fully penetrate the entire meniscus, which explains the notoriously poor healing following injury. The medial meniscus is injured more frequently than the lateral meniscus. Tears may occur in isolation, or in association with a major ligament injury such as an ACL tear. Injury results from twisting maneuvers or a rapid change of direction on a weight-bearing knee. Unlike other high-grade ligament injuries, meniscal injuries are usually characterized by only mild swelling, significantly less disability, and a continued ability to participate in sports activity. Patients may complain of joint line pain, delayed mild swelling, and locking (indicating the presence of

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a displaced meniscal fragment). Knee effusion develops more gradually than in ACL injuries, usually over 12 to 24 hours following injury. Joint line tenderness and McMurray’s and Apley’s tests aid in diagnosis. Treatment is primarily symptom-based. In the absence of mechanical symptoms, conservative therapy should be initiated. In cases involving younger patients, athletes, and those with large tears, mechanical symptoms, or a locked knee, surgical consultation is warranted. After any significant knee injury, the knee should be protected from further injury by placing the patient in a knee immobilizer and beginning the RICE protocol. The patient should be instructed to remove the knee immobilizer in order to perform daily range-of motion-exercises to avoid contracture and to maintain mobility. Orthopedic referral should occur within 1 week. MRI is the study of choice for noninvasive evaluation of ligament or meniscal injury and osteochondral fractures. The clinical pitfall to avoid is misdiagnosing a potentially serious knee injury as ‘‘just a sprain.’’ The clinician should check patients for other injuries in a systematic manner. Specific injuries not to be missed include quadriceps tendon rupture, patellar dislocation, knee dislocation, and meniscal or ligamentous injuries.

Appendix Physical examination tests Abduction (valgus) stress testdThis test assesses the integrity of the MCL. It is performed in extension and 30 of flexion. Place the patient in a supine position. One hand is placed on the lateral knee and the other hand grasps the forefoot and pulls it away from the midline. Instability indicates rupture of the MCL. Adduction (varus) stress testdThis test assesses the integrity of the LCL. It is performed in extension and 30 of flexion. Place the patient in a supine position. One hand is placed on the medial knee and the other hand grasps the forefoot and pulls it toward the midline. Instability indicates rupture of the MCL. Anterior drawer testdThis test assesses the integrity of the ACL. It is performed in 45 of hip flexion and 90 of knee flexion. Place the patient in a supine position. Sit on patient’s foot to anchor the lower extremity. Place hands around the knee, with the thumbs at the tibial tubercle, palpating the hamstring tendons with the fingers to ensure that they are relaxed. Grasp the proximal tibia with both hands and attempt anterior translation of the tibia. Assess for laxity and the presence of a discrete endpoint. Instability indicates rupture of the ACL. Apley’s grind testdThis test assesses the integrity of the menisci. Place the patient in a prone position with the knee flexed to 90 . Place one

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hand on the foot and the fingers of the other hand on the medial and lateral joint lines in turn. While partially flexing and extending the knee, rotate the tibia and apply downward pressure on the foot. Painful clicking during internal (lateral meniscus) or external rotation (medial meniscus) constitutes a positive test. Lachman testdThis test assesses the integrity of the ACL. It is performed in 20 to 30 of flexion. Place the patient in a supine position. Place one hand on the distal femur and grasp the proximal tibia with the other hand and attempt anterior translation. Assess for laxity and the presence of a discrete endpoint. Instability indicates rupture of the ACL. This is the single best test for the ACL, and it is more sensitive and accurate than the anterior drawer test. McMurray’s testdThis test assesses the integrity of the menisci. Place the patient in a supine position with the knee maximally flexed. Place one hand on the foot and the fingers of the other hand on the medial and lateral joint lines, in turn. With valgus stress, slowly extend the knee with the tibia either internally (lateral meniscus) or externally rotated (medial meniscus). Painful clicking constitutes a positive test. Pivot shift testdThis test assesses the integrity of the ACL. Place the patient in a supine position with the knee in full extension. Place one hand on the foot and with the other hand grasp the knee with the thumb behind the fibular head. Rotate the foot and tibia internally. Apply valgus stress to the knee as the knee is slowly flexed to 40 . The anterior tibia is subluxed on the femur with extension and initial flexion. It suddenly reduces (shifts) with further flexion, noticed by the ‘‘clunk’’ of reduction at 20 to 30 of knee flexion. Posterior drawer testdThis test assesses the integrity of the PCL. It is performed in 45 of hip flexion and 90 of knee flexion. Place the patient in a supine position. Sit on patient’s foot to anchor the lower extremity. Place hands around the knee, with both thumbs on top of the medial and lateral tibial plateaus. Attempt posterior translation of the tibia. Assess for laxity and the presence of a discrete endpoint. Instability indicates rupture of the PCL. Straight leg raise testdThis test assesses for the presence of a herniated disc. The SLR can be performed with the patient in the supine or seated position. Place one hand under the heel and grasp the knee with the other hand, keeping it fully extended. Monitor for the presence of radicular pain below the knee of the affected leg when the leg is elevated between 30 and 60 , especially if that pain is worsened by ankle dorsiflexion. Thompson’s testdThis test assesses the integrity of the Achilles tendon. For accuracy, the patient must be kneeling in a chair or in the prone position with the feet hanging over the edge. Squeeze the calf at its midportion and note the presence or absence of plantar flexion. Under normal circumstances, squeezing the calf causes plantar flexion. Absence

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of plantar flexion is a positive test and confirms a complete Achilles tendon rupture.

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