METHODOLOGICAL APPROACH TO EVALUATE THE EFFECTS OF MUSCLE REMOVAL ON ESTIMATED MUSCLE FORCES DURING WALKING IN PATIENTS AFTER RESECTION OF SOFT TISSUE SARCOMA IN THE THIGH

Abstract

Patients with lower extremity soft tissue sarcoma (STS) need to recover their walking ability while coping with lower-limb muscle loss due to tumor removal. However, the lack of information on walking after tumor removal hinders the development of gait rehabilitation strategies for such patients. The present study explored how patients walked after STS resection from the viewpoint of muscle forces. The effect of muscle removal and muscle strength asymmetry on estimated muscle forces was also investigated by iterating gait simulations for each patient using three different musculoskeletal models. These models differed based on whether or not the resected muscles were reflected in the model and whether or not residual muscle strength was scaled according to muscle strength measurements. Muscle forces during walking were estimated in six patients after thigh STS removal. Our results suggested that patients could walk using not only residual muscles that function similar to the resected muscles but also those that function differently (e.g., ankle plantarflexors). Gait simulations of patients with considerable muscle loss and those without a rectus femoris muscle were relatively sensitive to muscle removal.