Aim. The use of megaprostheses for knee reconstruction after distal femur resection in young bone sarcoma patients has become popular since early ′80. The authors reviewed their experience with different distal femur megaprostheses in children. Method. Clinico-radiographic evolution in a consecutive series of 113 children, that had implanted below age 15 (range 6-14) a distal femur megaprosthesis in the period 1984-2007, was analized. A modular implant was used in 97 cases with uncemented femoral stem (three different models along the period). The implant presented fixed-hinge joint in 78 cases while rotating-hinge knee was utilized in 19 cases. In 39 cases the fixed-hinge joint had a tibial component with a polished stem to allow the residual growth of proximal tibia; in two cases a mechanically extendable prosthesis was used. A custom-made noninvasive extendable prosthesis with cemented femoral stem and smooth uncemented tibial stem was used in 15 cases since 2002. Radiological and functional results were analysed and a statistical comparison of implant outcome according different stems was obtained. Results. At a 74 months follow-up (29-294), 72 patients are alive; but 43 of them (60%) had further surgery related to primary implant. Surgical revision rate was 88% (39% for mechanical failure) in long survivors treated before 1995 and 50% (14% with mechanical failure) in more recent cases (p< 0.05). Three long survivors progressed in time to total femur megaprostheses. Five out the 15 cases treated by custom made expandable prostheses were revised before completion of skeletal growth because of implant failure. Conclusion. In limb-salvage for bone sarcoma, megaprostheses are the preferred method to reconstruct distal femur in growing children, but a durable reconstruction is not easy to be achieved. The use of new devices specially addressed to younger patients deserves a serious scientific survey by musculoskeletal oncology community

We evaluated the clinical results and complications after extra-articular resection of the distal femur and/or proximal tibia and reconstruction with a tumour endoprosthesis (MUTARS) in 59 patients (mean age 33 years (11 to 74)) with malignant bone or soft-tissue tumours. According to a Kaplan–Meier analysis, limb survival was 76% (95% confidence interval (CI) 64.1 to 88.5) after a mean follow-up of 4.7 years (one month to 17 years). Peri-prosthetic infection was the most common indication for subsequent amputation (eight patients). Survival of the prosthesis without revision was 48% (95% CI 34.8 to 62.0) at two years and 25% (95% CI 11.1 to 39.9) at five years post-operatively. Failure of the prosthesis was due to deep infection in 22 patients (37%), aseptic loosening in ten patients (17%), and peri-prosthetic fracture in six patients (10%). Wear of the bearings made a minor revision necessary in 12 patients (20%). The mean Musculoskeletal Tumor Society score was 23 (10 to 29). An extensor lag > 10° was noted in ten patients (17%).

These results suggest that limb salvage after extra-articular resection with a tumour prosthesis can achieve good functional results in most patients, although the rates of complications and subsequent amputation are higher than in patients treated with intra-articular resection.

Cite this article: Bone Joint J 2013;95-B:1425–31.