Misdiagnosis and Radial Tunnel Syndrome: Considering the Distal Biceps Tendon

Radial tunnel syndrome (RTS) has long been a difficult therapeutic and diagnostic entity for upper extremity surgeons. The presentation is vague and the diagnosis is typically one of exclusion. Multiple clinical entities are known to mimic RTS, but little attention has been paid to the distal biceps. Experience suggests that insertional biceps tendonitis is a potential confounding diagnosis in suspected RTS and that magnetic resonance imaging (MRI) may be of diagnostic benefit in chronic cases before surgical intervention is undertaken. This study is a 13-patient case series. The included patients presented with proximal forearm pain and positive provocative maneuvers for RTS. All included patients were found to have distal biceps pathology on MRI evaluation. At final follow-up (average 6.9 years), all patients had resolution of symptoms with therapy aimed specifically at addressing the distal biceps tendon. A diagnosis of insertional biceps tendonitis could explain both the typical success with conservative treatment and the poor results from surgical intervention for RTS. (Journal of Surgical Orthopaedic Advances 28(1):35–40, 2019)
Key words: conservative management, distal biceps, misdiagnosis, radial tunnel syndrome, tendonitis, therapy