[Guepar anatomical trapeziometacarpal prosthesis].

Introduction: A choice of surgical techniques of treatment for trapeziometacarpal (TMC) Osteo-Arthritis (OA) have been described. Total arthroplasty is often used, especially in France. Many papers have been published, presenting various prostheses. In English literature, this device is not thoroughly used.
Materials and Methods: [corrected] Guepar total arthroplasty is a cemented ball-in-socket prosthesis in metal-polyethylene. It includes an anatomical stem available in 4 sizes. After failure of the conservative treatment, total arthroplasty must be reserved to elderly patients, painful, with OA Dell stage III or IV aligned or not. The trapezial height must be sufficient. The authors reports the preliminary results of 64 Guepar prostheses, anatomical new design, implanted since 1995.
Results: Results of 63 prostheses are presented. One removal had been necessary at 9 months for metacarpal loosening (failure). Mean follow-up was 29 months. Clinical results were judged excellent or good in all cases. Regarding the radiological results, no modifications has been observed in 56 cases. Six radiolucent lines without displacement of the implants has been noted, with no incidence on clinical results. In one case, a metacarpal stem penetrated into the medullary canal in the bone axis but without any clinical modifications.
Discussion and Conclusion: Clinically, in addition to pain relief, trapeziometacarpal prosthesis allows to preserve the first column length and to obtain a better opposition of the thumb as well of a better thumb-digits pinch, compared after trapeziectomy. Radiologically, as for total hip arthroplasty, the exact adaptation of an anatomical stem (new design) to the canal has probably a better prognosis at long term follow-up.