Peripheral arthropathy in hereditary sensory and autonomic neuropathy types III and IV.

BACKGROUND: To determine the features of the underlying destructive arthropathy in the peripheral joints of children with hereditary sensory and autonomic neuropathy (HSAN) type III and to compare and contrast this to the arthropathy noted in HSAN type IV, as both groups experience decreased pain perception. METHODS: From a database of 547 patients with HSAN type III and 32 patients with HSAN type IV, we performed a retrospective chart review and radiographic analysis of all patients who presented with joint swelling and deformity. Underlying joint pathology was classified as either osteonecrosis or Charcot arthropathy. RESULTS: In the HSAN type III population, 44 (8%; 22 males and 22 females) of the 547 patients had clinical evidence of arthropathy. In 42 patients, 48 joints demonstrated radiographic evidence of osteonecrosis; 45 (94%) of the 48 joints with osteonecrosis occurred in the lower extremity. In each case of osteonecrosis of the knee (n = 19), isolated involvement of the lateral distal femoral condyle was seen consisting of varying sizes of posterolateral osteochondral fragmentation. In the 32 patients comprising the HSAN type IV population, 18 (56%) were found to have radiographic findings consistent with Charcot arthropathy in a total of 30 affected joints. One patient demonstrated Charcot arthropathy of the spine and subsequent progressive spondylolisthesis. Nine patients (12 joints) also demonstrated osteomyelitis. CONCLUSIONS: In patients with HSAN type III, osteonecrosis is the initial lesion preceding destructive arthropathy. Osteonecrosis and osteochondral fragmentation were always isolated at the lateral distal femoral condyle in the knee. This pathology may be amenable to surgical reconstruction and fixation to stabilize the knee and prevent further degeneration. Hereditary sensory and autonomic neuropathy type IV was most commonly associated with Charcot arthropathy or joint subluxation and dislocation. Late secondary changes at the articular surface may make radiographic distinction difficult. Charcot arthropathy affected both sides of the involved joint with evidence of collapse and fragmentation. With osteonecrosis, the articular process was found to be more focal.