Sacroiliac joint abnormalities in paraplegics.

We studied 186 paraplegic patients to clarify the pathogenesis of the sacroiliac (SI) joint abnormalities reported in these patients. Partial or complete fusion of SI joints was noted in 47 patients (25%), and milder degrees of abnormalities of these joints were present in 27 patients (15%). The abnormalities differed from those seen in ankylosing spondylitis and were found more commonly in patients with high levels of cord injury. It is likely that trunk mobility is necessary to maintain integrity of SI joint and that absence of such mobility compromises SI joint structure in many paraplegics.