Objective: The prevalence of sacroiliac (SI) joint abnormalities in a primary low back pain population remains unresolved. The aims of our study were to define the prevalence of SI joint disease in this cohort, and to identify clinical features that might accurately predict radiographic changes in the SI joint and spine.
Methods: Lumbar spine and anteroposterior pelvis radiographs taken over a 3-year period for the evaluation of back pain at a major chiropractic college were scored for the presence of inflammatory or degenerative features. Data were subsequently extracted by means of a predetermined template from the clinical notes. The outcomes were correlated using Spearman's correlation coefficients.
Results: We identified 315 patients (173 men, 142 women), ages 18-60 years. Of these, 100 patients (31.7%) demonstrated SI joint abnormalities: 75 (23.8%) degenerative, 25 (7.9%) inflammatory. Sex was strongly associated with type of SI joint pathology; degenerative disease was predominantly found in women (68%), whereas inflammatory disease was predominantly found in men (63%). In women there was no correlation between degenerative SI joint abnormalities and degenerative changes in the lumbar spine. Of the clinical descriptors evaluated, none were associated with the radiographic findings with the exception of buttock pain, which was associated with inflammatory sacroiliitis. Neither being overweight nor pregnancy history was associated with degenerative changes in the SI joint.
Conclusion: In a primary back pain cohort, degenerative SI joint disease may be an under-recognized clinical entity. It is strongly influenced by sex but is unrelated to degenerative changes in the lumbar spine. Currently proposed clinical discriminators performed poorly in correlating with radiographic changes in the SI joint.