Background Several international guidelines recommend intra-articular (IA) corticosteroid injections for patients with hip OA experiencing moderate to severe pain and no responding to oral analgesics. Previous research has shown a systemic effect of an intramuscular (IM) gluteal corticosteroid injection in patients with subacromial impingement shoulder pain. A clinically relevant effect of IM corticosteroid injections would offer a less complex, alternative treatment for patients' episodes of increased pain in hip OA.
Objectives The trial aim was to assess the efficacy of an IM gluteal corticosteroid injection compared to a placebo injection on patients' reported hip pain severity in patients with hip OA, who were not responding on oral analgesics.
Methods Patients in primary and secondary care were included if they met the clinical ACR and radiographic (KL score ≥2) criteria for hip OA and scored a severity of hip pain ≥3 on a scale of 0–10 (0=no hip pain). Patients were randomized to receive either 40mg of triamcinolone acetate or saline (placebo) with an IA injection into the ipsilateral gluteus muscle. Primary outcome was severity of hip pain at 2 weeks, measured with numerical rating scale (NRS) in rest and during walking (0–10;0=no pain) and with the WOMAC pain subscale (0–100;0=no pain). Secondary outcomes included hip pain severity (NRS, WOMAC pain, ICOAP), function (WOMAC function), stiffness (WOMAC stiffness), adverse events, and medical co-interventions at 2, 4, 6, and 12 weeks follow-up. Statistical analyses were performed based on the intention to treat principle. Linear mixed models with repeated measurements were used to analyze between group differences. The models were adjusted for variables that changed the effect estimate >10%.
Results 107 of 422 screened patients were randomized. After informed consent, one randomized patient did not show up at the appointment for baseline measurement and subsequent injection and could, because of lack of data, not be included in the analyses. Finally, 52 patients in the corticosteroid injection group, and 54 in the placebo injection group were included in the analyses. 68% of the patients were female, and 25% were recruited by orthopedic surgeons. Mean age was 64 years (SD 11) and duration of OA was ≥1 year for 70%. At 2 weeks follow-up (table), the corticosteroid injection was statistically significant and clinically relevant associated with hip pain reduction at rest (coefficient -1.3, 95% CI -2.3 to -0.3) compared to placebo. The corticosteroid injection was also associated with significant hip pain reduction at 4, 6 and 12 weeks. Moreover, at almost all follow-up measurements the estimates showed significant differences in favor of the corticosteroid injection on WOMAC pain, function, stiffness and total score, and ICOAP. No significant differences between groups were found for adverse events and medical co-interventions.
Conclusions An IM gluteal corticosteroid injection was effective in hip pain reduction compared to placebo injection in patients with hip OA at 2 weeks folow-up. Moreover, the effect of the corticosteriod injection prolonged the entire 12 week follow-up period.
Disclosure of Interest None declared