Elbow & Forearm MCQs

A 25-year-old man has an isolated flexor digitorum profundus laceration just proximal to the distal interphalangeal (DIP) flexion crease of his ring finger. The tendon ends are trimmed, removing 10 mm from each end (secondary to fraying) and the tendon repaired. Four months later, he reports limited finger motion of the long, ring, and small fingers. He cannot fully extend his wrist and all joints of the 3 fingers simultaneously. He has full passive flexion but cannot actively completely close his fingers into a fist. What is the most likely cause?A. QuadrigiaB. Intrinsic tightnessC. Lumbrical plus deformityD. Disruption of the tendon repai

DISCUSSION: The MRI scan reveals a transection of the biceps muscle. The underlying brachialis is intact. This injury can occur as a result of a cord wrapped around the upper arm. Care should be taken to ensure that there is no concurrent vascular injury.

The structure identified is the distal biceps tendon. Rupture of this tendon causes weakness in both flexion and supination. The biceps tendon does not affect extension or pronation.

This patient has rupture of the lateral ulnar collateral ligament (LUCL), producing posterolateral rotatory instability (PLRI). This is best demonstrated with a positive lateral pivot shift test.PLRI can be diagnosed using the lateral pivot shift or posterolateral drawer. According to O’Driscoll, the elbow dislocates in 3 stages from lateral to medial (circle of Horii). Stage 1 involves disruption of the LUCL and partial/total disruption of the LCL complex (creating PLRI). Patients have pain with varus stress. Stage 2 includes disruption of the anterior capsule from incomplete elbow posterolateral dislocation. Stage 3 is divided into:(a) Disruption of all soft tissues surrounding/ including the posterior MCL except for the anterior bundle. This bundle forms the pivot around which the elbow dislocates in a posterior direction by way of a posterolateral rotatory mechanism; and (b) complete disruption of the MCL.O'Driscoll et al. describe PLRI diagnosed in 5 patients who had elbow dislocation using the posterolateral rotatory instability test, which they describe as being analogous to the test for lateral rotatory instability of the knee after ACL rupture. They believed the condition was laxity of the LUCL, which allowed transient rotatory subluxation of the ulnohumeral joint and secondary dislocation of the radiohumeral joint, without radio-ulnar joint dislocation. They recommended repair of the LUCL to eliminate PLRI.Sanchez-Sotelo et al. retrospectively described 12 cases of direct repair and 33 ligamentous reconstructions for PLRI. 86% were satisfied with the procedure. Better results were obtained with patients with post-traumatic etiology, instability at presentation, and those with augmented reconstruction with tendon graft (compared with ligament repair alone).Figure A shows structures on the lateral side of the elbow. The corresponding labels are seen in Illustration A. Illustration B shows the lateral pivot shift (also known as the posterolateral rotatory instability test).Incorrect Answers:

A 50-year-old woman has had acute weakness in her dominant hand for 6 weeks. Before noticing the onset of weakness, she experienced several weeks of vague discomfort in her shoulder and forearm, generalized fatigue, and a low-grade fever. There is no history of trauma. An examination reveals weakness of thumb and index finger distal interphalangeal (DIP) joint flexion. Electrodiagnostic testing shows fibrillations and positive sharp waves in the flexor pollicis longus and index flexor digitorum profundus muscles. The next appropriate step isA. observation.B. corticosteroid injection.C. immediate surgical decompression.D. tendon transfers.

The lateral epicondylar epiphysis is the last to ossify in the elbow at age 12 to 14 years in males. The first secondary ossification center to ossify is the capitellum, which ossifies during the first 6 months of life. Next is the radial head, ossifying between age 3 and 6 years. The medial epicondyle appears between 5 and 7 years; the trochlea and olecranon at 8 and 10 years, respectively. In females, the appearance of ossification centers is about a year earlier than males.

Widening of the medial ulnohumeral joint on an AP radiograph is only visible after overlengthening of the radial head by 6 mm or more. At least in this cadaver study, the most sensitive method was to visually assess the lateral aspect of the ulnohumeral joint with the radial head resected and then with the trial radial head in place. This method allows detection of any overlengthening.

The patient shown underwent distal biceps repair with a button technique. Among the reports in the literature, the most commonly noted complication associated with this technique is lateral antebrachial cutaneous nerve irritation. Re-rupture, radioulnar synostosis, and posterior interosseous nerve injury can occur, but are not as common as lateral antebrachial cutaneous nerve injury.

Osteochondritis of the capitellum is characterized by pain, swelling, and limited motion. Catching, clicking, and giving way also can occur. It commonly affects athletes who participate in competitive sports with high stresses, such as pitching or gymnastics.

The patient presents with lateral epicondylitis, which typically involves the origin of the extensor carpi radialis brevis (ECRB). ECRB is in the mobile wad compartment and its antagonist muscle is flexor carpi ulnaris.Lateral epicondylitis is an overuse injury, typically secondary to repetitive pronation and supination motion in extension, that leads to inflammation of the ECRB origin at the elbow. Histological analysis typically shows vascular hyperplasia and disorganized collagen. Clinically, patients will have pain over the lateral elbow exacerbated by resisted wrist extension. ECRB, the most commonly involved muscle origin, is innervated by the deep branch of the radial nerve and inserts on the base of the 3rd metacarpal. As it is radial wrist extensor, its antagonist is the ulnar sided wrist flexor.Brummel et al. reviewed the clinical presentation and management options for lateral epicondylitis. They report acute symptoms in younger patients and chronic symptoms in older patients. NSAIDs, extensor stretching and activity modification are the mainstay of nonsurgical treatment.Bunata et al. studies 85 cadavar elbows to determine anatomic factors contributing to tennis elbow. They found that the ECRB undersurface rubs against the lateral capitellium in elbow extension leading to tendinosis.Illustration A is cross-sectional diagram of the forearm with muscle bellies labeled. Notice the location of ECRB in the mobile wad. Illustration B is a coronal T2 MRI showing fluid signal and undersurface tearing near the extensor origin as can be seen in lateral epicondylitis.Incorrect Answers:1-4: The ECRB is in the mobile wad and its antagonist is flexor carpi ulnaris. All other answers are incorrect.

A provocative test for medial epicondylitis can be elicited by applying resistance to a patient with their fist clenched, wrist flexed and pronated.Medial epicondylitis is an overuse syndrome of the flexor-pronator mass. The pronator teres (PT) and flexor carpi radialis (FCR) are thought to be most affected with this condition. It is most common in the dominant arm and occurs with activities that require repetitive wrist flexion/forearm pronation. Patients are most tender over the origin of PT and FCR at the medial epicondyle. Resisting a patient with their fist clenched, wrist flexed and pronated can cause worsening of their pain. This maneuver can be used as a provocative test for this condition.Cain et al. reviewed elbow injuries in throwing athletes. They comment that the common flexor-pronator muscle origin provides dynamic support to valgus stress in the throwing elbow, especially during early arm acceleration and help produce wrist flexion during ball release.Amin et al. reviewed the evaluation and management of medial epicondylitis. They report that medial epicondylitis typically occurs in the fourth through sixth decades of life, the peak working years, and equally affects men and women. Physical therapy and rehabilitation is the main aspect of recovery from medial epicondylitis, once acute symptoms have been alleviated.Illustration A shows a video of this provocative test for medial epicondylitis. Incorrect Answers:

DISCUSSION: Essex-Lopresti injuries affect axial stability of the forearm. Injury to the interosseous membrane or the triangular fibrocartilage complex can result in proximal migration of the radius. REFERENCES: Morrey BF, Chao EY, Hui FC: Biomechanical study of the elbow following excision of the radial head. J Bone Joint Surg Am 1979;61:63-68. Coleman DA, Blair WF, Shurr D: Resection of the radial head for fracture of the radial head: Long-term follow-up of seventeen cases. J Bone Joint Surg Am 1987;69:385-392.

DISCUSSIONCertain complications are more strongly associated with the approach and surgical procedure for elbow pathology. With a 2-incision distal biceps repair, heterotopic ossificationwith a radial-ulnar synostosis is a concern. This complication can be minimized through irrigation of bone debris and care to avoid dissection between the radius and ulna. With a single-incision distal biceps repair, the lateral antebrachial cutaneous nerve is retracted during the procedure. Numbness on the lateral side of the forearm is common, although often temporary. During arthroscopic debridement for lateral epicondylitis, injury to the radial UCL can occur, leading to posterolateral rotatory instability of the elbow. The modified Jobe technique for UCL reconstruction typically involves an ulnar nerve transposition during the procedure. Numbness and tingling in the fourth and fifth digits are concerns when this procedure is performed.

The most commonly injured nerve during a distal biceps repair is the lateral antebrachial cutaneous nerve (LABCN). Injury to this nerve would result in lateral volar forearm numbness.Distal biceps avulsions can be partial or complete. Indications for surgical management include young, healthy patients who do not wish to sacrifice function, as well as partial biceps avulsions that do not respond to conservative management. Repair of a distal biceps avulsion can be approached through either an anterior one-incision technique or a two-incision technique (Boyd-Anderson). The one-incision technique uses the interval between the brachioradialis (radial nerve) and pronator teres (median nerve), while the two-incision technique uses this same interval in addition to a second posterolateral elbow incision. The lateral antebrachial cutaneous nerve is the most common nerve injured during either approach.Kelly et al. retrospectively reviewed 74 distal biceps tendon repairs, and found five sensory nerve paresthesias. The lateral antebrachial cutaneous nerve was most commonly injured, followed by the superficial radial nerve.Cain et al. retrospectively reviewed 198 distal biceps tendon repairs, and found a 36% complication rate. Lateral antebrachial cutaneous nerve paresthesias were found in 26%, while radial sensory nerve paresthesias were found in 6%, and posterior interosseous nerve (PIN) injury in 4%.Illustration A shows the close relationship between the lateral antebrachial cutaneous nerve (LABCN) and the distal biceps. Illustration B shows the sensory nerves of the upper extremity and their respective areas of innervation.Incorrect Answers:

DISCUSSION: The patient has a type I (Hahn-Steinthal) capitellar fracture that is best seen on the lateral radiograph. If a fracture fragment is seen proximal to the radial head, a capitellar fracture is the most likely injury because radial head fractures do not migrate proximally. The fragment is large enough for fixation. Excision is the preferred treatment for small shear osteochondral type II (Kocher-Lorenz) capitellar fractures. Closed reduction usually is not successful because of rotation of the displaced fragment. REFERENCES: Mehdian H, McKee M: Management of proximal and distal humerus fractures. Orthop Clin North Am 2000;31:115-127. Ring D, Jupiter J, Gulotta L: Articular fractures of the distal part of the humerus. J Bone Joint Surg Am 2003;85:232-238.

DISCUSSION: Ninety percent of injuries to the proximal radius in children are radial neck fractures, and 50% of these fractures are through the metaphyseal bone. The remaining 50% are Salter-Harris type I or II fractures. These radiographs show a fracture of the radial head and subluxation of the radius anteriorly. Most congenital radial head dislocations are posterior lateral. Nonsurgical treatment modalities are unlikely to be successful due to the wide displacement of the fracture fragments, as well as dislocation of the radial head.

This is a rare injury, and it is important to recognize both the proximal and distal concurrent injuries. In the past, the radial head excision has been the primary form of treatment, but this has shown poor long-term results; silicone replacement has been fraught with reactive synovitis. Radial ulnar synostosis is a complication, not a planned course of treatment.

The patient presents with lateral epicondylitis and develops posterolateral rotatory instability (PLRI) of the elbow due to excessive arthroscopic debridement. The correct answer is reconstruction of the lateral ulnar collateral ligament using palmaris longus or gracilis allograft.PLRI is the result of an incompetent lateral ulnar collateral ligament (LUCL), a component of the elbow lateral collateral ligament complex. The LUCL originates on the lateral epicondyle of the humerus and inserts upon the supinator crest of the ulna. When deficient from acute trauma or from repetitive microtrauma, the elbow becomes rotationally unstable with elbow extension, supination, and an applied valgus force. In this case, the patient has had iatrogenic damage to the LUCL from an arthroscopic release of the extensor carpi radialis brevis (ECRB) for treatment of lateral epicondylitis. This patient exhibits an important manifestation of this: a positive chair pushup test. This test is positive when pushing off of a chair with a supinated forearm causes pain and instability. Due to the chronicity of the injury (3 months) and his persistent symptoms of instability (pain and clicking) the patient would benefit from surgical reconstruction of the damaged LUCL using either palmaris longus or gracilis allograft.Kelly et. al. reviewed the known major and minor complications of elbow arthroscopy among 473 consecutive cases at their institution from 1980-1998. The most common complications were transient nerve palsies in 10 patients. Among them, the majornerves involved included the anterior interosseous nerve, posterior interosseous nerve, ulnar nerve, superficial radial nerve, and medial antebrachial cutaneous nerve. The risk of iatrogenic nerve injury was increased among patients with rheumatoid arthritis. The most frequent complication was prolonged drainage from the portal sites.Calfee et. al. reviewed the management of lateral epicondylitis. The authors suggest open or arthroscopic surgical debridement of the common extensor origin after failure of rest, orthoses, nonsteroidal drugs, physical therapy, cortisone and platelet-rich plasma injections. They do acknowledge that excessive debridement may compromise lateral elbow stability and cause PLRI.O'Brien et. al. described the surgical techniques for managing PLRI, including an open technique for chronic injuries or revision treatment. In this setting, the authors suggest use of palmaris or gracilis allograft for reconstruction.Figures A and B are an axial and coronal T2 weighted MRI of an elbow demonstrating signal intensity in the origin of the ECRB, consistent with lateral epicondylitis.Incorrect Answers:

Closed central slip injuries treated nonsurgically require extension splinting of the PIP joint. DIP joint active range of motion is allowed during this time period. This allows the connections between the lateral bands and the central slip to pull the central slip distally with DIP joint active motion, minimizing the gap across the central tendon injury and keeping the DIP joint from getting stiff as well.

The extensor carpi radialis brevis is most often cited as the anatomic location of pathology in lateral epicondylitis. Histologic examination demonstrates noninflammatory tissue, primarily angiofibroblastic tendinosis though normal tendon histology is also present. There is usually no evidence of acute inflammation or chondroblastic tissue, or significant calcium deposition.