Functional analysis and the importance of ligament reconstruction after soft tissue sarcoma surgery around the knee joint -a Tokai musculoskeletal oncology consortium study.

Background: Surgery for soft tissue sarcoma (STS) around the knee joint often requires extensive tissue resection, leading to significant functional impairment. This study aimed to evaluate knee function following surgery for STS around the knee joint and to assess the importance of ligament reconstruction in cases where the collateral ligaments were excised.

Methods: We included 63 patients treated surgically at eight hospitals participating in the Tokai Musculoskeletal Oncology Consortium between 2008 and 2019. Tumor development within 3 cm proximal to the superior patella and 3 cm distal to the tibial articular surface was defined as the area surrounding the knee joint. The median patient age was 61 years (25 males; median follow-up period, 62 months). The median tumor size was 60 mm. The histological types included 18 undifferentiated pleomorphic sarcomas (UPS), 17 myxoid liposarcomas, 7 myxofibrosarcomas (MFS), and 21 others. Knee function was assessed using the Lysholm score.

Results: The 5-year overall survival rate was 91%. Factors significantly associated with lower Lysholm scores were female sex (p = 0.01), tumor histology such as MFS and UPS (p = 0.01), adductor muscle resection (p < 0.001), lateral collateral ligament (LCL) resection (p = 0.002), patellar tendon resection (p = 0.019), and medial collateral ligament (MCL) resection (p = 0.024). The group with ≥ 4 resected muscles had significantly lower Lysholm scores than the group with < 4 resected muscles (p = 0.003). Multivariate analysis showed that the factors significantly associated with lower Lysholm scores were adductor muscle resection, female sex, and tumor histology (MFS and UPS). Among patients who required excision of the LCL or MCL, those who underwent ligament reconstruction had better functional scores than those who did not (p = 0.06).

Conclusions: This study identified factors that significantly affected post-resection function in patients with STS of the knee joint. These findings may assist in predicting postoperative function after STS surgery around the knee joint, suggesting that ligament reconstruction may give a suggestive benefit for improving the function in cases requiring resection of the LCL or MCL.