Disorders of the sacroiliac joint are challenging to diagnose. This is partially due to similarity in symptom presentation to other lumbar spinal disorders and poor visibility of the joint on imaging studies. The pubic symphysis is clearly visualized in the anteroposterior view on plain film radiographs. As a closed ring, changes in the anterior and posterior portion of the pelvis may be reciprocal. The purpose of this study was to assess the correlation between pubic symphyseal changes observed on X-ray and SI joint disorders.
Thirty patients with a confirmed diagnosis of SI joint disorders were compared with 30 patients with low back pain without the evidence of SI joint involvement. Plain film radiographs were blinded and independently reviewed by two orthopedic surgeons. Changes in the pubic symphysis were classified as (0) no change, (1) osteoarthritic degeneration, (2) vertical displacement, or (3) ligament ossification.
There was no significant difference between groups in age, gender, or parturition status. The majority of both groups were female. Mean (±SD) subject age was 61 (±11) and 59 (±9) years, and parity was 44% and 39% for the study and control groups, respectively. The prevalence of observable changes in the pubic symphysis was 97% in the study group and 30% in the control group (p < 0.001).
Results of this study suggest that pubic symphyseal changes in the presence of low back pain and positive provocative maneuvers could serve as a marker for SI joint disease. Further investigation of the potential relationship between SI joint symptoms and symphyseal changes should be examined.