Dysfunction of the Lateral Branch of the Superficial Radial Nerve Associated with Radial Collateral Ligament Injuries of the Thumb Metacarpophalangeal Joint: A Case Series with Cadaveric Dissections

The lateral branch of the superficial radial nerve (SRN) may undergo a neuropraxic stretch injury following radial collateral ligament (RCL) injury to the thumb metacarpophalangeal joint. This case series presents seven athletes who sustained a previously undescribed injury pattern combining dysfunction of the lateral branch of the SRN associated with RCL injury. Successful stabilization of the joint as well as relief of pain was obtained with surgical repair of the RCL, neurolysis and wrapping of the nerve with a tissue engineered allograft product, and, when necessary, excision of a post-traumatic osteophyte. Diagnostic workup along with surgical treatment is presented. Additionally, cadaveric dissections confirmed the course of this nerve, proximity to surrounding structures, and its innervation of the MP capsule. (Journal of Surgical Orthopaedic Advances 29(4):195–198, 2020)

Key words: radial collateral ligament, lateral branch of superficial radial nerve, thumb metacarpophalangeal joint