Complication inhabituelle à 20 ans d’une arthroplastie trapézo-métacarpienne

Abstract

Trapeziometacarpal joint arthroplasty is a reliable method for treating TM osteoarthritis, with the major benefit of rapid pain relief and recovery after surgery. Despite recent advances in prosthetic design, with a 90% survival rate at 10 years, there remain complication risks that cannot be ignored. The most common complications are prosthetic dislocation and trapezial cup loosening. To our knowledge, flexor tendon rupture has not been reported after TM joint arthroplasty. We report a unique case of total asymptomatic trapeziometacarpal prosthesis dislocation, accidentally discovered after the occurrence of a rupture of the index flexor tendons more than 20 years after surgery in an 82-year-old woman. Formal testing was informative and confirmed the lack of normal function of the superficial and profundus flexor tendons of her left index finger. There was no sign of carpal tunnel compression. She showed satisfactory thumb mobility with a Kapandji score of 8/10 and a grip strength of 10 kg. She had near-comparable mobility to the contralateral healthy side. X-rays showed a total dislocation of the prosthesis stem, whose proximal end was located next to the carpal tunnel. We undertook surgical exploration via a carpal tunnel approach. The prosthesis stem was located at the radial base of the carpal tunnel. Both index flexor tendons were ruptured. The stem was removed and not replaced. The reconstruction of the index profundus flexor tendon was performed by transfer of the ring finger flexor superficialis tendon using the Pulvertaft technique in zone 3. Immobilization was considered unnecessary. Active and passive rehabilitation were performed daily and initiated on postoperative day 1. Follow-up at 6 months showed satisfactory motion of the thumb without any pain, a Kapandji score of 8/10, a grip strength of 12 kg, satisfactory flexion of the index and ring fingers, and a Quick-DASH score of 29.55/100. We noticed a clinical shortening of the thumb explained by significant shortening of M1 on radiographs. This case presents a rare case of complication of trapeziometacarpal joint arthroplasty, since dislocation went unnoticed for a considerable time. Our strategy was to avoid any loss of range of motion. Prosthesis removal was efficient and ring finger superficial flexor tendon transposition allowed immobilization to be avoided. This observation adds a new clinical complication of the trapeziometacarpal prosthesis, and shows an example of how it was promptly managed.