Abstract
The proximal tibiofibular joint (PTFJ) is susceptible to osteoarthritis (OA), making it a rare but potential source of lateral knee pain. Because PTFJ OA is a rare presentation of knee pain, no first-line treatment has been established and it can be missed in evaluation before total knee arthroplasty. We report an unusual case of a 59-year-old man who presented with advanced OA of both the knee and PTFJ, along with a progressive peroneal nerve palsy due to a large compressive ganglion cyst from the PTFJ. He was treated with concurrent total knee arthroplasty, peroneal nerve decompression, and resection of the fibular head and ganglion cyst, resulting in full recovery from his arthritic pain and resolution of his peroneal neuropathy. He remains free of symptoms without instability 3 years from the index surgery.