Nineteen patients in the glucocorticoid group reported 27 nonserious adverse events, compared with 13 patients in the placebo group who reported 18 adverse events.
The authors said the greatest effects of the glucocorticoid injection were seen at 4- to 12-week follow-up (the secondary outcomes of the study), instead of at the 2-week follow-up. For example, at 4-week follow-up, the glucocorticoid injection was associated with a significant hip pain reduction at rest (between-group difference = –1.2; 95% CI, –2.1 to –0.2; P = .01) and during walking (difference = –1.1; 95% CI, –2.0 to –0.2; P = .01). At 6 weeks, the corresponding figures for hip pain reduction were –1.4 at rest (95% CI, –2.4 to –0.5; P = .005) and –1.4 while walking (95% CI, –2.3 to –0.4; P = .004). The between-group differences were still significant at 12 weeks while at rest (difference = –1.2; 95% CI, –2.3 to –0.2; P = .02) and during walking (difference = –1.3; 95% CI, –2.2 to –0.3; P = .01).
Significant differences in favor of the glucocorticoid injection overall occurred on the WOMAC subscale scores for pain, function, and stiffness, as well as total Hip disability and Osteoarthritis Outcome Score for pain and total, intermittent, and constant pain measures on the Intermittent and Constant Osteoarthritis Pain scale. At 12 weeks, the between-group difference on the WOMAC total score was –9.4 (95% CI, –17.8 to –0.9; P = .03).
The researchers said it was surprising that hip pain reduction after IM glucocorticoid injection was still present at a similar degree at 12 weeks since previous studies had shown the effect usually peaked after 1-3 weeks.