Comparison of allograft-prosthetic composite reconstruction and modular prosthetic replacement in proximal femur bone tumors: functional assessment by gait analysis in 20 patients.

BACKGROUND AND PURPOSE: The methods of reconstruction for proximal femur bone tumors that are used most often include modular prosthetic replacement and allograft-prosthesis composite reconstruction. In modular prostheses, the abductors are detached from the insertion and then reinserted into the implant, and the iliopsoas is detached and left free. In the allograft-prosthesis composite, the detached tendons are fixated to the graft. We assessed whether the latter procedure provides functional advantages regarding gait. PATIENTS AND METHODS: We studied 2 groups of 10 patients, each with prosthetic reconstruction of the proximal femur either with modular prosthetic replacement or with allograft-prosthesis composite. Functional performance was analyzed by gait analysis 2.5-10 years after surgery. At that time, all the patients had good function according to the Musculoskeletal Society score. RESULTS: Walking speed was reduced in all patients, and especially in patients with modular prosthetic replacement. Different hip extension patterns during late stance were found in the 2 groups. Surface EMG showed a typical prolonged muscle co-contraction pattern during gait, which was more evident in modular prosthetic patients. INTERPRETATION: Although both procedures provided good functional outcome in the long-term follow-up, gait analysis revealed mechanical changes during gait that were probably related to the muscle reinsertion procedure. Direct fixation of the muscles to the bone graft appeared to result in a more efficient muscular recovery.