Functional evaluation in distal femoral endoprosthetic replacement for bone sarcoma

A multicenter study of successfully treated patients (mean age, 36.7 years) with a minimum 1-year followup (average, 35.4 months) after distal femoral endoprosthetic replacement for bone sarcoma was done using the 1987 and 19 93 versions of the Musculoskeletal Tumor Society, the Short Form-36, and th e Toronto Extremity Salvage Score functional evaluation criteria. Fifty-six patients (28 women and 28 men) fulfilled the criteria. Thirty-one Kotz pro stheses (fixed hinge, uncemented) and 25 Modular Replacement System Prosthe ses (rotating hinge, cemented) were used. Thirty-five patients walked witho ut aids, 19 used a cane, and two used crutches or a walker. The Musculoskel etal Tumor Society 1987 mean score was 28.1. The Musculoskeletal Tumor Soci ety 1993 mean score was 80.4. The Toronto Extremity Salvage Score mean was 81.6. The Short Form-36 Physical Component Score had a mean of 43.2 and Men tal Component Score mean of 54.2. The two groups of implants were comparabl e, except for the length of bone resection. Multivariate regression analysi s revealed that patient age, existence of a pathologic fracture, and type o f prosthesis all significantly accounted for differences in functional outc ome as measured by the Musculoskeletal Tumor Society 1993, the Toronto Extr emity Salvage Score, and the Short Form-36 Physical Component Score scales. Although both implants provided satisfactory function, the Musculoskeletal Tumor Society 1993 and the Toronto Extremity Salvage Score results were si gnificantly better with the Modular Replacement System prosthesis. The effe ct of possible differences among surgeons or institutions was not addressed .