Long-term evaluation of Silastic trapezial arthroplasty in patients with osteoarthritis.

This study of 151 Silastic trapezial arthroplasties evaluates the long-term radiographic and clinical results in patients with osteoarthritis. A radiographic grading system was developed to objectively evaluate and quantify changes seen at the implant-bone contact areas, within the metacarpal medullary canal and distal pole of the scaphoid. Trapezial arthroplasties studied on average of 51 months after implantation revealed that in 56% (85 of 151) of scaphoids cysts had developed, and 74% (111 of 151) of the metacarpals had intramedullary radiolucency and/or cysts. Histopathologic evaluation of the areas of radiographic changes demonstrated silicone synovitis. Statistical analysis revealed that the radiographic changes in the scaphoid and medullary canal of the metacarpal were not directly related to time. Patient satisfaction, found to be 84% (127 of 151) of the study population, did not correlate with the grade of scaphoid or metacarpal radiographic change. This systematic radiographic grading system has been found useful in the long-term durability evaluation of Silastic trapezial arthroplasties.