Conventional Chondrosarcoma Diagnosed After Total Knee Arthroplasty: A Case Report.

Three years after a total knee arthroplasty, the patient presented with persistent pain and an enlarging intra-articular periprosthetic mass. Attempts at nonoperative treatment and arthroscopic debridement were unsuccessful. A biopsy revealed a large, intermediate-grade chondrosarcoma involving the joint space. The patient was treated with an above-the-knee amputation, but eventually died as a result of widespread metastatic disease.To our knowledge, this is the first reported case of chondrosarcoma involving the joint space that was diagnosed after total knee arthroplasty. This case demonstrates the need for increased awareness when there are suspicious clinical findings and the importance of diagnosing and/or treating tumors prior to or shortly after total joint arthroplasty.