Relationship Between Sacroiliac Joint-related Pain and Spinopelvic Mobility

Study Design. A case-control study. Objective. To evaluate the relationship between sacroiliac joint-related pain (SIJ-RP) and spinopelvic mobility. Summary of Background Data. No specific radiological findings are available for the diagnosis of SIJ-RP. A previous study reported that a higher pelvic incidence and sacral slope (SS) values were significantly associated with sacroiliac joint pain. The concept of spinopelvic mobility, which is evaluated by the differences between SS in the standing and sitting positions, has been the focus of hip and spine surgeries in recent years. Materials and Methods. The SIJ-RP group comprised patients diagnosed with SIJ-RP based on physical findings and their response to analgesic injections. No other lumbar or hip joint diseases were observed. The non-SIJ-RP group comprised patients with lower back pain for reasons other than SIJ-RP. Radiographs of the lateral view of the pelvis in the standing and sitting positions were evaluated for all patients. We compared and analyzed the backgrounds, SS in the two positions, and difference in SS between the two positions in both groups. Results. In total, 245 patients were included in the study, with 49 and 196 patients in the SIJ-RP and non-SIJ-RP groups, respectively. More female patients experienced SIJ-RP than male patients (P=0.0361). There were significant differences between the groups for SS in standing (P=0.0076), sitting (P=0.0005), and those with a difference between sitting and standing of <5 degrees (P=0.0278) in the univariate analyses. Logistic regression analyses, after adjustment for age and sex, revealed significant differences between the groups with an SS difference <5 degrees (P=0.0088; 95% confidence interval, 1.280-5.519), with an odds ratio of 2.7. Conclusion. On evaluating spinopelvic mobility, we found that SIJ-RP was related to hypomobility of the sacrum, which could indicate the hypermobility of the sacroiliac joint.