Intercalary defects reconstruction of the femur and tibia after primary malignant bone tumour resection. A series of 13 cases.

INTRODUCTION Performing intercalary segment reconstruction after malignant bone tumour resection results in both mechanical and biological challenges. Fixation must be solid enough to avoid short-term or mid-term mechanical failure. The use of an allograft or autograft must ensure long-term survival of the reconstruction. The goal of this study was to analyse the clinical and radiological outcomes of these reconstructions. PATIENTS AND METHODS Thirteen patients were operated on eight femurs and five tibias. The median age was 20 years old (range 14-50). The most common diagnosis was osteosarcoma. The median resection length was 15cm (Q1-Q3: 6-26). A plate was used for fixation in nine cases and an intramedullary locked nail in four cases. An isolated bone autograft was used in two cases, an isolated bone allograft in one case, a dual autograft-allograft composite in six cases, and vascularised fibula and allograft combination in four cases. RESULTS The cumulative probability of union was 46% (95% CI: 0-99%) at 1 year; at the final follow-up, union was achieved in 12 patients (92%). Because of non-unions, 13 iterative procedures were needed to obtain these results. A non-displaced fracture of a cuboid-shaped tibial graft occurred in one patient, which was treated conservatively. Three infections occurred. DISCUSSION The results of intercalary segmental defects reconstruction after bone tumour resection were good, both from an oncologic and radiological point-of-view. One or more iterative procedures are sometimes needed to finally obtain bone union. We prefer to use a free rectangular cuboidal tibial graft since reconstruction with a vascularised autograft is technically more difficult. The choice of fixation methods is still controversial and no approach was found to be superior. LEVEL OF EVIDENCE Level IV. Retrospective study.