Primary bone and soft tissue sarcomas are an exceptionally rare form of cancer, collectively accounting for only 1% of all malignancies diagnosed. Sarcomas often occur in the patients' extremities and treatment typically involves limb salvage surgery with bone and/or muscle resection. These surgeries often leave the patients with disfigurements, psychological trauma, and functional disabilities. Perhaps, the most difficult and life-altering decision that patients (and their parents) with primary bone sarcomas about the knee joint have to make, involves choosing the type of surgical procedure that will provide them with the outcome that meets their functional as well as aesthetic expectations. In literature, the quality of life for patients with osteosarcoma around the knee joint after three different surgical procedures, that is, amputation, endoprosthetic reconstruction and rotationplasty was evaluated. There was found that patients treated with rotationplasty showed significantly higher functional scores compared to the two other groups of patients. Also, researchers investigated the long-term quality of life after bone sarcoma surgery around the knee joint and found that, despite the functional disability, survivors were busy with work, study, relationships, and sometimes they have founded a family. Most published reports in the literature on assessment of gait in the lower-extremity sarcoma survivors were focused on bone sarcoma patients after wide resection and endoprosthetic reconstruction. To the knowledge of the investigator, there has been no published studies on gait analysis after resection of soft tissue sarcomas (STS) of the lower extremity. The rare and heterogeneous aspects of STS and the paucity of knowledge of movement strategies in these patients hinder the development of effective rehabilitation protocols for recovering movement after resection of STS in the lower limb.