We performed 20 de la Caffiniere trapeziometacarpal arthroplasties for osteoarthritis occurring only at this joint and reviewed all patients after periods of up to ten years. Eighteen arthroplasties were satisfactory postoperatively, although all 20 patients had a satisfactory range of motion and only one experienced pain after surgery such that it impeded normal function. Failure occurred in two patients and was due to overreaming of the trapezium during surgery and a traumatic dislocation. A radiolucency between the prosthesis and bone was observed in one arthroplasty, although this patient was asymptomatic. We recommend arthroplasty using the de la Caffiniere prosthesis as a satisfactory method of treatment for the osteoarthritic trapeziometacarpal joint.

Augmentation of the acetabular component of total hip replacements is a method of increasing stability and preventing recurrent dislocation. We report a series of mechanical experiments designed to evaluate the turning moments and angles required to dislocate standard, long posterior wall and two different augmented prostheses.