Case 53
History and Physical Examination
A 35-year-old industrial worker presents with a 3-month history of persistent lateral elbow pain. He denies any specific traumatic injury and denies any numbness in the hand or upper extremity. He reports worsening of symptoms with repetitive work and no improvement with nonsteroidal medications.
Range of motion of the elbow is normal, as is stability and strength of the elbow and hand. He is neurovascularly intact in the upper extremity. No tenderness is palpable around the elbow except for 5 cm distal to the lateral epicondyle. The patient is nontender directly over the lateral epicondyle and immediately distal to it. No tenderness exists in the posterolateral gutter. The patient has a negative Tinel sign for the ulnar nerve medially.
Differential Diagnosis
1. Lateral epicondylitis
2. Posterior interosseous nerve compression
3. Extensor musculature overuse
4. Elbow arthritis
Radiologic Findings
Anteroposterior (AP) and lateral radiographs of the elbow reveal no abnormalities.
Diagnosis
Posterior Interosseous Nerve Compression. Accurate diagnosis of posterior interosseous nerve compression is difficult. It can be easily confused with lateral epicondylitis, and lateral epicondylitis often coexists with posterior interosseous nerve compression. Likewise, differentiation of posterior interosseous nerve compression from simple extensor musculature overuse symptoms is difficult as well. The absence of findings suggestive of lateral epicondylitis, in combination with the tenderness exhibited in the area of the arcade of Froshe, suggests posterior interosseous nerve compression. No objective evidence of motor denervation with extensor musculature weakness was seen, but weakness is an unusual finding in posterior interosseous nerve compression.
Patients usually complain of dull, aching dorsal lateral forearm or elbow pain worsened with activities. This pain is often described as “burning” and radiates along with the anatomic course of the forearm extensor muscles. Patients sometimes complain of grip weakness and reduced stamina of the forearm muscles. Rest and activity restrictions tend to improve symptoms, only to recur with resumption of normal activities.
Nonoperative management of posterior interosseous nerve compression consists of activity restrictions and protective splinting. Oral nonsteroidal antiinflammatory medications may be helpful as well. It is important to remember that lateral epicondylitis often coexists with posterior interosseous nerve compression and treatment of the lateral epicondylitis, which includes an exercise program and nonsteroidal medications, along with an occasional local corticosteroid injection, is indicated. Failure of nonoperative treatment to improve posterior interosseous nerve compression, particularly if lateral epicondylitis symptoms resolve, serves as an indication for surgical intervention.
PEARLS
• Selective injections in the area of localized pain is often helpful in accurately determining the site of pain on the lateral aspect of the elbow. A selective lidocaine injection around the arcade of Froshe will often completely eliminate the patient’s pain when compression of the posterior interosseous nerve at this site is present.
• Approach to the posterior interosseous nerve through the muscle splitting approach of the mobile wad musculature allows for excellent visualization and is routinely employed by the authors. Often, after incising the skin and subcutaneous tissues, the posterior interosseous nerve can actually be palpated deep to this musculature, making the approach and identification of the nerve easier.
