BJJ - 2026-06-01 - Journal Article
Implant survival and limb salvage rates after combined proximal tibial and distal femoral endoprosthetic replacement.
Baird CAE, Archer JE, Green NM, Burahee A, Riaz M, Ahmed Kamel S, Stevenson J, Kurisunkal V, Evans S
Topics
Key Takeaway
Combined proximal tibial and distal femoral endoprosthetic reconstruction achieves 10-year revision-free implant survival of 61% and limb salvage of 69%, with infection as the leading cause of long-term limb loss.
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Summary
This study evaluated revision-free implant survival and limb salvage in 34 patients undergoing composite distal femur plus proximal tibia endoprosthetic reconstruction for primary bone tumors around the knee at a single center over 27 years. Kaplan-Meier analysis showed 5- and 10-year revision-free survival of 77% and 61%, and limb salvage of 81% and 69%, respectively. Mean MSTS score was 53% and mean extensor lag was 25°, reflecting the functional compromise inherent to this construct.
Key Limitation
The heterogeneous cohort mixing primary reconstructions (n=8) and revision cases (n=26) conflates two distinct clinical scenarios with likely different baseline failure risks, making survival estimates difficult to apply to either group independently.
Original Abstract
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.