PurposeThe aim of the present study is to understand the clinical outcomes of a novel hydroxyapatite-coated (HA-coated) titanium screw for surgical treatment of SI joint dysfunction. BackgroundThe mainstay of therapy for disorders of the sacroiliac (SI) joint has been non-operative treatment including activity modification, non-steroidal anti-inflammatory drugs, and physical therapy. SI joint injections provide diagnostic information and occasional durable therapeutic benefit. When these modalities fail, sacroiliac joint fusion may be recommended. ObjectiveThe objective of this study is to describe the clinical outcomes of a novel HA-coated titanium screw for surgical treatment of SI joint dysfunction. MethodsThis study is a retrospective Institutional Review Board-exempt chart review of 45 consecutive patients who underwent minimally invasive SI joint fusion with a novel HA-coated screw system. Patients were diagnosed based on North American Spine Society guidelines and evidence-based criteria. Clinical assessments were collected, evaluated, and compared preoperatively and at 3, 6, 12, and 24 months postoperatively. ResultsMean patient age was 68.8 ± 9.4 years, and 61.7% of patients were female. Of the 44 patients, nine underwent bilateral SI joint fusion, while the remaining were unilateral. Screw size ranged from 10 × 35 mm to 10 × 50 mm. Mean preoperative visual analog scale (VAS) SI pain scores decreased significantly by a mean of 6.1 points at 12 months postoperatively (P < 0.001). Mean Oswestry Disability Index (ODI) scores significantly improved from 52.3% at baseline to 11.3% at 3-month follow-up, 11.5% at 6 months, 10.9% at 12 months, and 9.5% at 24 months, leading to improvements of 41.0, 40.8, 41.4, and 42.8 points, respectively. ConclusionThe clinical outcomes of SI joint fusion using an HA-coated screw system to treat sacroiliitis demonstrated significant decreases in VAS SI and ODI scores at 3, 6, 12, and 24 months.