Total Knee Arthroplasty and Atypical Cartilaginous Tumor/Enchondroma of the Distal Femur

Enchondroma is a common benign chondrogenic tumor, which typically occurs in the short bones of hands and feet. However, when affecting the long bones, it is difficult to rule out the low-grade chondrosarcoma, called atypical cartilaginous tumor (ACT), because of the highly similar clinical and radiologic features. This study reports 2 patients with advanced knee osteoarthritis, scheduled for total knee arthroplasty, who had a distal femoral lesion on imaging suggestive of ACT/enchondroma. We believe that the treatment of these patients could be a challenge for arthroplasty surgeons. This is because it might be difficult to decide whether a periarticular chondral tumor of an osteoarthritic knee is malignant and changes the plan. In this report, we described our approach to address both knee osteoarthritis and ACT/enchondroma of the distal femur. To the best of our knowledge, this issue has not yet been discussed in the literature.