Gait analysis: Comparative evaluation of conventional total knee replacement and modular distal femoral megaprosthesis

Background: Gait alterations have been studied with computer-assisted gait analysis after megaprosthetic replacement for tumors around the knee. It has never been proven that megaprostheses affects gait more than total knee arthroplasty (TKA); this study aims to compare via gait analysis patients who underwent megaprosthesis with patients with TKA. Methods: We analyzed 26 patients with a megaprosthetic replacement of the distal femur and 21 patients with a standard TKA. For each subject computerized gait analysis was performed. Range of motion (ROM) of the knee was recorded, Quality of Life and functional evaluation in the oncologic group were assessed with the Musculoskeletal Tumor Society (MSTS) questionnaire, while Short Form-36 (SF-36) scores were calculated for both groups. Results: All patients walked slower than healthy people (P < 0.05). Gait analysis showed a lower cadence than in the healthy population but no significant difference between the two groups. A longer swing and a shorter stance phase were detected in the megaprosthetic sample. The osteoarthritis group showed greater flexion during the phase of loading response, even if this was lower than the contralateral limb or healthy population. There was a statically significant difference between the healthy limb and the operated one in both groups regarding ROM, but no significant difference was registered between the two implants. MSTS score and most of SF-36 parameters showed no significant differences compared with literature data. Conclusions: Gait analysis shows little discrepancy between the two groups; gait pattern abnormalities do not affect patients with a megaprosthetic replacement more significantly than patients undergoing TKA.