Mid- to long-term results of allograft-prosthesis composite reconstruction after removal of a distal femoral malignant tumor are comparable to those of the proximal tibia.

PURPOSE: To compare the outcomes of allograft-prosthesis composite for reconstruction after malignant tumors at the distal femur and proximal tibia.

METHODS: Case-control study of 24 patients with distal femur tumor and 21 with proximal tibia tumor. Union of the allograft-host interface was assessed by the International Society of Limb Salvage criteria, and complications according Henderson. Functional outcome was evaluated by the Musculoskeletal Tumor Society (MSTS) score, Western Ontario and McMaster Universities (WOMAC) score, and pain by a visual analog scale.

RESULTS: The median follow-up in the femoral group was 11.4 (range 2.3-25.0) years, and 10.1 (range 2.2-25.0) in tibial group. Incorporation of the allograft was successful in more than 90% in both groups. Tumor location was not significant predictor for allograft failure in multivariate analysis. Aseptic prosthesis loosening occurred in two patients in either group, and another patient in the tibial group had a breakage of the tibial insert. Excluding local recurrences and amputations, the prosthesis survival at 10 years was 94.1% in the femoral group, and 83.3% in the tibial group (n.s.). For the patients with preserved limb, the median MSTS score was 23.6 in the femoral group and 22.8 in tibial group (n.s.). Likewise, there were no significant differences in median WOMAC score (n.s.) or VAS pain (n.s.).

CONCLUSIONS: Allograft-prosthesis composite is an effective procedure for distal femur tumors related to the graft, prosthesis survival, and functional outcomes. The results are comparable to those for proximal tibial tumors.

LEVEL OF EVIDENCE: Therapeutic study, Level III.