Arthroplasty of a Charcot Knee in a Patient With Congenital Insensitivity to Pain

Hereditary sensory and autonomic neuropathies (HSANs) include hereditary disorders that cause congenital insensitivity to pain. Moreover, patients diagnosed with such disorders are known to have genetic mutations that alter their deep pain sensation, making them more prone to developing bone and joint complications such as repetitive fractures, joint swelling, and Charcot arthropathy. Neuropathic arthropathy (Charcot joint) is a rare and relatively poorly understood condition; it is suggested to be caused by autonomic dysfunction and repetitive microtrauma and characterized by instability and joint destruction. Diagnosing the idiopathic Charcot joint is challenging and is considered to be a diagnosis of exclusion. In addition, there are limited cases of Charcot knees managed by arthroplasty. Patients with Charcot knees are commonly characterized by profound bone loss, diffuse synovitis, and instability in the knee joint. In this article, we report the case of a 13-year-old patient with known NTRK1 gene mutation who presented with recurrent knee joint swelling episodes and instability without pain. She was diagnosed with Charcot knee joint and underwent right hinged total knee replacement. At one-year follow-up, she continued to have good knee stability and an overall functional gait. Our findings suggest that managing Charcot knee joint with total knee replacement in patients with HSAN may show improvement in terms of stability, swelling, and overall gait.