Age predicts therapeutic outcome of imaging-guided sacroiliac joint injections, whereas osteoarthritis grade does not: A retrospective single-center study.

BACKGROUND: Sacroiliac joint (SIJ) disorders are among the most common causes of chronic low back pain. Imaging-guided SIJ injections are widely used as an early diagnostic tool, with corticosteroid often added to provide a therapeutic component. Evidence of factors predicting the therapeutic outcome of these injections remains scarce.

PURPOSE: To evaluate the effect of SIJ osteoarthritis and other potentially relevant demographic, imaging, and procedural factors on the patient-reported therapeutic outcome of imaging-guided SIJ injection.

MATERIAL AND METHODS: This retrospective single-center study included 101 patients who underwent specialist-referred imaging-guided SIJ injection between 2010 and 2023. Medical records and procedural reports were reviewed to collect relevant patient information, and associated SIJ MRIs and CT scans were reanalyzed for osteoarthritis, sacroiliitis, and bone marrow edema by an experienced musculoskeletal radiologist. The association of demographic, imaging, and procedural factors with the therapeutic injection outcome was assessed using logistic regression modeling.

RESULTS: Of 101 patients who underwent an imaging-guided SIJ injection, 72 (71.3%) met the inclusion criteria. The mean age was 52.2 (SD 14.2) years, and 30 patients (41.7%) achieved a positive therapeutic response. Increasing age was significantly associated with a lower likelihood of a positive outcome, with the probability decreasing on average by 9.4% for each additional year of age (OR 0.91 [95% CI 0.84-0.99]). Neither SIJ osteoarthritis grade nor other demographic, imaging, or procedural factors showed a significant association with injection outcome.

CONCLUSION: Increasing age was significantly associated with a lower likelihood of achieving a positive therapeutic SIJ injection outcome, while SIJ osteoarthritis grade showed no association.