Silastic replacement of the trapezium for arthrosis--a twelve year follow-up study.

Thirty-three patients with 39 Swanson silastic trapezium implants have been studied. Three years after operation no dislocation or evidence of implant wear was found, but re-examination at an average of 12 years after operation revealed dislocations and implant wear in about half of the cases. Cyst formation in surrounding carpal bones was found in twenty cases. The result in terms of pain relief and thumb function was good and comparable to the three-year follow-up. A significant correlation was found between weakness of the pinch grip and dislocation of the implant. No correlation was found between pain and dislocation of the implants, nor between pain and presence of intraosseous cysts.