Post-Paralytic Knee Arthropathy Following Spinal Ependymoma Resection Treated With Bilateral Hinged Total Knee Arthroplasty.

Post-paralytic knee arthropathy (PPKA) is a rare and underrecognized cause of progressive joint degeneration, driven by chronic muscle imbalance that leads to abnormal joint mechanics and loading patterns. We report the first known case of bilateral PPKA following spinal ependymoma resection treated with staged hinged total knee arthroplasty (H-TKA). The patient developed severe, progressive deformities over 18 years with preserved sensation, distinguishing this condition from Charcot arthropathy, which is characterized by rapid joint destruction and profound sensory loss. Staged H-TKA restored alignment, improved stability, relieved pain, and enabled functional recovery. This case highlights the unique modern pathophysiology of PPKA and supports H-TKA as a viable treatment option.