A modular femur-tibia reconstruction system.

A 26 piece modular system for the reconstruction of the bones of the lower extremity from the femoral head to the distal third of the tibia is described. This modular system can be implanted without cement and allows for the intraoperative determination of the amount of resection necessary. The implant material is the well-known cast, Co-Cr-Mo alloy Vitallium. From 1982 to the end of 1985, 52 patients were treated with this cementless tumor endoprosthesis of the Kotz Modular Femur-Tibia Reconstruction System (KMFTR) at the University of Vienna, Department of Orthopedics. The locations of the tumors were: proximal femur (28), distal femur (17), and proximal tibia (7). In two cases a total femur was implanted and in another patient a total knee. Indications for the resection of the bone segments and joints concerned included primary bone tumors, metastases, and loosening of conventional endoprostheses and tumor resection endoprostheses. Twenty-one patients with an average follow up of 20.4 months and a minimum follow up of 1 year were evaluated according to Enneking's criteria. Eight patients had proximal femoral replacement. The results were excellent in two, good in five, and fair in one. Eleven patients had undergone replacement surgery in the knee joint area. The overall rating showed five excellent results, four good and two fair. One patient with a total femoral replacement had multiple bone metastases with polytopic pain and was no longer available for regular assessment. Another patient with a total knee replacement suffered a rupture of the patellar ligament after 10 months and had to be revised. Radiologically we have observed excellent bone incorporation of the prosthesis in 15 of 25 evaluated patients. Ten cases showed no changes in radiologic features as compared to the initial findings. These were patients with short follow up periods. Although complications did occur in these major surgical interventions, the final results were very satisfactory and the patients were subjectively content with the operation.