Arch Hand Microsurg.  2023 Dec;28(4):281-286. 10.12790/ahm.23.0032.

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

• Oh SH
• Kang JH

• KMID: 2548600
• DOI: http://doi.org/10.12790/ahm.23.0032

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.

Keyword

Locked metacarpophalangeal joint; Sesamoid arthritis; Sesamoidectomy; Trigger thumb

Figure

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  Fig. 1. Preoperative clinical image. (A) Extension and (B) flexion of the thumb.

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  Fig. 2. Preoperative imaging studies. (A) Plain radiography showed deformity of the radial sesamoid bone and a bone fragment around the metacarpophalangeal joint (MCPJ). (B) Computed tomography scan and magnetic resonance imaging revealed a bird beak-shaped radial sesamoid bone and entrapment in the MCPJ, which caused mechanical MCPJ blocking.

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  Fig. 3. (A) Inability to flex the metacarpophalangeal joint (MCPJ) of the thumb. (B) The radial sesamoid bone with arthritic changes was resected. (C) After radial sesamoidectomy and tenolysis, the patient recovered a passive range of motion in the MCPJ of the thumb. (D) Severe decortication and arthritic changes in the sesamoid surface were observed on the articular side (above) and the volar side (below).

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  Fig. 4. (A) Limited range of motion of the thumb during extension (left) and flexion (right) before the third surgery. (B) Tenolysis of the flexor tendon with severe adhesion and tendon thickening. (C) Adipofascial flap elevation for the volar plate defect. (D) Postoperative range of motion (extension [left] and flexion [flexion]) of the thumb under wide-awake anesthesia.

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  Fig. 5. Range of motion of thumb at the final follow-up at our clinic. There was mild extension lag of the interphalangeal joint of the thumb; however, the range of motion had improved. The patient resumed activities of daily living without other complications. (A) Extension. (B) Flexion.

Reference

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