Tabetic Arthropathy of the Knee: From Neurosyphilis to Prosthetic Reconstruction

Tabetic arthropathy of the knee is a rare, late complication of neurosyphilis, resulting from the loss of deep sensation and proprioception caused by tabes dorsalis. Long regarded as a historical curiosity since the penicillin era, it is now re-emerging alongside the global resurgence of syphilis, and should be considered whenever massive, strikingly painless joint destruction is observed — this radio-clinical dissociation explains the usual diagnostic delay. Diagnosis relies on the convergence of clinical findings (Charcot's triad, Argyll Robertson pupil), radiological features, and serology, after excluding other causes of neuropathic arthropathy. Long viewed as a contraindication to total knee arthroplasty because of the risk of instability and loosening, this arthropathy can now benefit from rotating-hinge arthroplasty combined with bone reconstruction tailored to bone stock (autograft, allograft, or metal augments). This strategy is illustrated by our single-center experience of 5 cases (2009-2020), with a marked functional improvement (IKS-Function score: 33 to 80 points) and restored joint stability in all patients, at the cost of prolonged follow-up given the infectious and mechanical risks inherent to this condition. Overall, tabetic knee arthropathy should be considered whenever massive, painless joint destruction is observed; early recognition and appropriate prosthetic management provide a durable functional benefit.