Long-term clinical outcomes of modular endoprosthetic reconstruction for primary bone tumours of the proximal femur.

Endoprosthetic reconstruction of the proximal femur is a well-accepted technique in the treatment of bone tumours. However, controversies remain regarding the optimal reconstructive technique. For instance, there is little evidence to support resurfacing of the acetabulum. Our preferred technique during recent years was hemiarthroplasty with a bipolar femoral head and an attachment tube for tendinous reinsertion. Aim of this study was to evaluate the long-term clinical outcomes of these reconstructions. All consecutive patients in whom a MUTARS® proximal femoral replacement was performed between 1999 and 2023 for a primary bone tumour were retrospectively evaluated, with a minimum follow-up of 24 months. Sixty-four patients matched inclusion criteria. Mean age was 52 years (8 to 89). Chondrosarcoma was the predominant diagnosis (n = 37, 58%), followed by osteosarcoma (n = 16, 25%). At review, 36 patients (56%) were alive. Median follow-up was 10.1 years (IQR 4.5-14.7). Fifty-four reconstructions (84%) were bipolar hemiarthroplasties. Twenty-eight (44%) implants were silver-coated. Median reconstruction length was 18 cm (8 to 45). Dislocation occurred in five bipolar hemiarthroplasties (9%) and in three total hip arthroplasties (33%). Aseptic loosening was not observed. One periprosthetic fracture was observed (2%). Deep infections occurred in eight reconstructions (13%). The cumulative incidence of mechanical failure at five, ten, and fifteen years was 11.8% (95% CI 3.4-20.3), 22.6% (95% CI 10.1-35.2), and 29.7% (95% CI 14.4-44.9). In our experience, bipolar hemiarthroplasty appears to be a viable technique for reconstruction of the proximal femur after bone tumour resection, with a low rate of mechanical failure and acetabular wear at long-term follow-up.