STUDY AUTHORS TOUT STEROID INJECTIONS FOR HIP OA EVEN THOUGH THEIR RESULTS SHOWED NO BENEFIT
June 29, 2022 - Steroid joint injections remain a popular treatment for joint pain even though studies have found they have no clear benefit. Injecting the hip joint is technically more difficult and typically only performed by orthopedic surgeons or sports medicine doctors. A study published in the British Medical Journal looked at the effects of steroid hip injections in patients with hip osteoarthritis (OA).
The study enrolled 199 patients with hip OA and moderate to severe pain for at least 6 weeks. Patients were randomized to one of three groups: (1) steroid hip injection (triamcinolone 40 mg/lidocaine 1%, 4 ml) + education, (2) lidocaine injection (5 ml of 1%) + education, (3) education only. Education included exercises and other guidance on pain control. The injections were done under ultrasound guidance, and the injection groups were single-blinded. The primary outcome was average pain on a 0 - 10 scale over 6 months, with measurements at 2 weeks, 2 months, 4 months, and 6 months. Over the course of the study, the average pain score was lower in group 1, with a difference of 1.43 between group 1 and group 3 (p<0.001) and 0.52 between group 1 and group 2 (p=0.14). Pain scores for group 1 were significantly better than group 3 at 2 weeks and 2 months but not at 4 months or 6 months. Pain scores for group 1 were significantly better than group 2 at two weeks only. [SH review]
In their conclusion, the authors state that "In community settings of musculoskeletal services, we have shown that an ultrasound guided intra-articular hip injection of corticosteroid and local anaesthetic, administered with advice and education, is a clinically effective treatment for rapid and sustained symptom response compared with advice and education alone for people with hip osteoarthritis." Their conclusion seems odd since the steroid injection was no better than the lidocaine injection, and the comparison between steroid and education only is not meaningful since patients in the education group were unblinded. Furthermore, 94% of patients at baseline stated a preference for injection, which means the education group had a negative bias toward their assigned therapy.
The steroid group had better pain control than the lidocaine group at 2 weeks, which may be secondary to systemic absorption of the steroid, a phenomenon that has been observed in other joint injection studies. From 2 months on, there was no significant difference in pain.
This study illustrates the importance of taking a closer look at a trial's methods as opposed to trusting the author's findings. A brief review of this study even appeared in the JAMA, demonstrating how quickly misinformation can spread. [JAMA review]