Abstract
Primary intra-articular sarcomas are rare and present with nonspecific symptoms such as pain or swelling. Due to nonspecific symptoms, patients may undergo routine diagnostic arthroscopy, which ultimately leads to sarcoma diagnosis. Here we present four patients with intra-articular sarcomas of the knee diagnosed after arthroscopy. The goal of this study is to highlight the importance of including malignant bone and soft-tissue sarcomas in the differential diagnosis of patients with nonspecific knee symptoms. A case series was developed from a retrospective review of prospectively collected data from our institution's orthopedic oncology database. Patients who underwent arthroscopic procedures on the knee and who were diagnosed with intra-articular sarcomas postoperatively from 2014 to 2019 were identified. All patients underwent diagnosis, staging, and multidisciplinary evaluation and treatment. Clinical characteristics, oncologic considerations, and surgical outcomes are described. Four patients with intra-articular sarcomas of the knee diagnosed after arthroscopy for non-oncologic concerns were identified: two synovial sarcomas, one Ewing sarcoma of bone, and one osteosarcoma. All surgical plans and treatment options were significantly affected by the previous arthroscopic procedures. One patient underwent above-the-knee amputation; one patient underwent extra-articular wide resection of the knee, including portal sites with distal femur/total knee reconstruction; one patient underwent rotationplasty, and one patient was treated with therapeutic radiation (no surgery). All patients received chemotherapy. Although intra-articular sarcomas are rare, orthopaedic surgeons must remain vigilant when proceeding with arthroscopic procedures if the clinical history, physical exam, and imaging findings are not perfectly aligned.