Pyogenic infections of the sacro-iliac joint.

In 3 cases of pyogenic infection of the sacro-iliac joint, the diagnosis was difficult. Limp, buttock pain and upper sciatica were the most common presenting symptoms. Differential limitation of hip motion, positive straight leg raising, a positive Gaenslen test and pain on pelvic compression were frequent fingings. Increased E.S.R., W.B.C. count and fever were seen in 2/3 cases. Plain and tomographic X-rays are often helpful but bone scan has been helpful in localizing early lesions. Treatment after early diagnosis may consist of antibiotics and immobilization alone while in the more chronic cases surgical drainage and debridement may be necessary.