Aims Combined endoprosthetic replacement of the ipsilateral distal femur and proximal tibia is rarely performed. It is usually undertaken to achieve limb salvage after resection of primary bone tumours around the knee. This study aims to determine the viability of ‘composite’ endoprosthetic reconstruction around the knee, and report implant survival and limb salvage rates. Methods A retrospective review of a prospectively maintained departmental database was undertaken to identify patients who had undergone composite endoprosthetic reconstruction around the knee. The primary outcome of interest was revision-free implant survival. Secondary outcomes were amputation-free survival, the Musculoskeletal Tumor Society (MSTS) score, and extensor lag. A total of 34 patients (21 male and 13 female) with a mean age of 32 years (14 to 66) underwent surgery between January 1997 and November 2024, and were followed up for a median interval of 12.6 years (IQR 3 to 14). Results The oncological diagnoses were osteosarcoma (n = 26), Ewing’s sarcoma (n = 5), and one each of giant cell tumour of bone, spindle cell sarcoma, chondrosarcoma, and synovial sarcoma. Of the eight primary and 26 revision cases, the pooled five- and ten-year revision-free implant survival rates were 77% (95% CI 63 to 94%) and 61% (95% CI 45 to 83), respectively (Kaplan-Meier). Resection length and construct:stem ratio had no impact on revision rate. Limb salvage at five and ten years was 81% (95% CI 68 to 96) and 69% (95% CI 54 to 89), respectively. Range of motion outcomes were available in 30 patients and MSTS scores in 20 patients. The mean extensor lag was 25° (10° to 50°) and the mean MSTS score was 53% (27% to 67%). Conclusion Composite endoprosthetic reconstruction around the knee after tumour resection is a viable limb salvage option in the primary or revision setting; however, it does carry a risk of reoperation in the medium and long term. The leading reason for failed limb salvage in the long term is infection. We recommend careful patient selection and preoperative discussion before contemplating composite reconstruction. Cite this article: Bone Joint J 2026;108-B(6):827–834.
Baird et al. (Mon,) studied this question.