Injury of the distal biceps at the musculotendinous junction

Abstract

Although complete rupture of the distal biceps tendon at the osseous insertion has been well documented in the literature, musculotendinous ruptures of the distal biceps remain exceedingly uncommon. In this report, we present a series of 6 distal biceps musculotendinous ruptures in 6 different patients, verified either with magnetic resonance imaging or by direct visualization at surgical exploration. In 5 of 6 patients, a single traumatic injury was reported, whereas the sixth reported 2 episodes of injury and pain occurring approximately 1 week apart. A common mechanism of injury seems to prevail in this type of injury: glenohumeral elevation with the elbow extended and the forearm in supination. Although surgical outcomes of distal biceps osseous avulsions frequently lead to excellent results, the surgical options for musculotendinous junction injuries are limited, with outcome studies lacking. These 6 patients, who did not undergo repair, obtained a mean score of 97.5 on the Mayo Clinic Performance Index for the Elbow. Symptoms of musculotendinous injury to the distal biceps are similar to tendinitis or complete or partial avulsion of this muscle-tendon unit. The examination reveals an intact distal biceps tendon. In patients with a mechanism of injury consistent with a musculotendinous injury of the distal biceps, radiographic modalities, particularly magnetic resonance imaging, are recommended to confirm the diagnosis to differentiate it from the more common distal biceps tendon avulsion, or partial rupture, to limit the morbidity associated with potentially unnecessary operative procedures.