Subluxation of the sacroiliac joints in a black female with ankylosing spondylitis.

A 55-year-old black female with ankylosing spondylitis (AS) is described. The patient had a severe flexion attitude secondary to a rotational subluxation at the sacroiliac joints with subsequent bony ankylosis. The sacroiliac abnormality has not been reported in AS patients. Sacroiliac joint laxity during multiple pregnancies might have contributed to the subluxation. The importance of this anatomic site in evaluating the surgical correction of the postural deformities of AS is stressed.