Pseudo-Stener lesion due to proximal ulnar collateral ligament rupture: A case report.

INTRODUCTION AND IMPORTANCE: Ulnar collateral ligament (UCL) ruptures are a common injury of the thumb. The UCL will most commonly rupture at the distal insertion. It has been proposed that a partial or non-displaced tear can be managed non operatively. However, a complete rupture that occurs at the distal insertion will commonly not be able to heal non-operatively due to the interposition of the adductor aponeurosis. This clinical finding is known as a Stener lesion, first described by Bertil Stener in 1962.

CASE PRESENTATION: We present the case of a 63-year-old-woman with instability of the thumb, pain, and a small mass at the ulnar side of the metacarpal phalangeal joint (MCPJ).

CLINICAL DISCUSSION: A Stener lesion mass is commonly palpated on the ulnar MCPJ due to the ligament being trapped proximally to the overlying aponeurosis. Our patient mistakenly presented with a Stener lesion that was intraoperatively discovered to be a mass of granulation tissue. This patient underwent repair of the UCL and was able to return to unrestricted daily activities after six weeks.

CONCLUSION: This case highlights an unusual rupture pattern and shows the proper surgical techniques for repairing such an injury. It is imperative to restore joint stability to prevent decreased grip strength and early onset of osteoarthritis of the MCPJ.

LEVEL OF EVIDENCE: Therapeutic Level 3B.