Radial Tunnel Syndrome: A Diagnostic Challenge – A Case Report

Case Diagnosis: Radial Tunnel Syndrome in the setting of Mild Segmental Radial Neuritis

Case Description or Program Description: A 36-year-old right-handed female presented with an 18-month history of right lateral elbow pain and bilateral hand tightness and numbness. Symptoms included dorsal hand and finger numbness radiating from the lateral elbow, worsened by wrist extension and finger use. Two Orthopedic Surgeons previously diagnosed lateral epicondylitis and recommended physical therapy (PT) without relief. Prior EMG/NCS and cervical MRI were unrevealing. Examination showed increased sensation over the lateral dorsal right hand, positive Maudsley test, and positive Tinel’s sign over the radial tunnel. Diagnostic ultrasound confirmed mild segmental radial neuritis of the posterior interosseous nerve without extrinsic compression.

Setting: An outpatient physical medicine and rehabilitation clinic within an urban academic medical center.

Assessment/Results: The patient’s ultrasound findings and clinical presentation supported RTS. She was referred for PT with nerve gliding and eccentric strengthening. After a few PT sessions, she reported mild improvement and opted to continue. If symptoms persist, ultrasound-guided radial tunnel corticosteroid injection was recommended.

Discussion (relevance): Radial Tunnel Syndrome (RTS) is an entrapment neuropathy of the posterior interosseous nerve (PIN) within the radial tunnel, often presenting with lateral forearm pain and motor sparing. It is frequently misdiagnosed as lateral epicondylitis or cervical radiculopathy, delaying treatment. Standard electrodiagnostic studies are often normal, and high-resolution ultrasound can detect neuritis. Conservative management, including PT, activity modification, and corticosteroid injections and/or hydrodissection, is the mainstay, with surgery for refractory cases.

Conclusions: This case highlights RTS as a diagnostic challenge and underscores ultrasound’s utility when electrodiagnostic studies are inconclusive. Early recognition and tailored management may prevent chronic pain and functional impairment. Further studies are needed to refine diagnostic criteria and optimize treatment pathways.