Sesamoid arthritis with locked metacarpophalangeal joint misdiagnosed as trigger finger: a case report

Abstract

Locked metacarpophalangeal joint (MCPJ) is mainly caused by joint pathologies, although tendinopathy is also a possible cause. Furthermore, it can be misdiagnosed as tendinopathy with triggering symptoms. Herein, we present a 60-year-old housewife with thumb flexion inability lasting for 4 months. Three weeks previously, she visited another clinic and was misdiagnosed with trigger thumb. Her symptoms did not resolve after trigger thumb surgery. At our clinic, physical examination and imaging studies were conducted. Sesamoid arthritic change with entrapment in the MCPJ was found, and the entrapped sesamoid bone inhibited flexion of the MCPJ of the thumb. Based on the examinations, radial sesamoidectomy was planned. After surgery, the patient recovered a passive full range of motion immediately. Despite a rehabilitation program, at 6 months postoperatively, severe stiffness and contracture at the MCPJ were noted. Therefore, a second operation with tenolysis and volar plate release was conducted under wide-awake anesthesia. Intraoperatively, severe adhesion was observed in flexor tendon, volar plate release was performed, and small defects were found in the volar plate when thumb was fully extended. To prevent secondary healing of the volar plate defect, a dorsoradial adipofascial flap was used. At 6 months after the second surgery, the patient’s range of motion in the MCPJ had improved, and she resumed activities of daily living without other complications. Hand surgeons frequently misdiagnose conditions as trigger finger if there is triggering or locked-joint symptoms. An accurate preoperative diagnosis with a detailed physical examination and imaging studies are essential for better operative results.