Disclosures: Aaron J. Lin, MD: No financial relationships or conflicts of interest

Case Description: Low back pain that started 2.5 years ago during pregnancy, initially in left low back but migrated to right low back, progressively worse, now rated 6/10 in severity, radiates down the bilateral lateral legs to posterior calves and great toes, positive for numbness in the great toes. Trialed 10 to 15 sessions of physical therapy with mild improvement, trialed rest and NSAIDs without efficacy. Worse with leg press and elliptical exercises. Physical exam positive for pain with forward flexion, FABER and negative SLR, Gaenslen’s, FADIR, hip internal and external rotation bilaterally. Previous MRI showed diffuse bulging of posterior annulus of L4-L5 disc.

Setting: Outpatient Musculoskeletal Clinic

Patient: 39 year old female with a medical history of polycystic ovarian syndrome and migraines Assessment/

Results: X-ray of the SI joints was obtained that showed osteitis condensans ilii (OCI). The patient was reevaluated after 6 sessions of physical therapy with significant improvement of pain, about 90% relief. Further laboratory testing was not performed.

Discussion: OCI is a benign cause of axial low back pain with no clearly identified etiology, though the most likely theory is that mechanical strain affecting the auricular portion of the ilium causes premature arthritis and sclerosis. First described radiologically in 1926 and has a prevalence of 0.9 to 2.5% in the general population with several case reports reporting occurrence in females following pregnancy.

Conclusion: OCI is a rare but benign disease state that should be considered in the differential diagnosis in patients with axial low back pain.There is no routinely recommended treatment but it has been treated with a range of modalities including rest, NSAIDs, therapy, as well as surgical resection of the affected bone. It is important to keep other inflammatory and noninflammatory diagnoses on the differential as OCI shares characteristics clinically though presents radiographically unique.

Level of Evidence: Level V

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PM&R Meeting Abstracts - https://pmrjabstracts.org/abstract/axial-low-back-pain-not-always-what-it-seems/