When oral painkillers and physical therapy do not sufficiently work, injection of corticosteroids can relieve the pain of patients with knee osteoarthritis. The general practitioner can inject the corticosteroids directly into the knee joint (intra-articular) or the gluteus muscle (intramuscular). Researchers at Erasmus MC’s Department of General Practice found that intramuscular injection worked as well as intra-articular injection after 8 weeks. They published their results in JAMA Network Open.
The researchers studied 145 patients with knee osteoarthritis, randomly divided into two groups: 74 received an intramuscular injection at the general practitioner, and 71 received an intramuscular injection. At 2, 4, 8, 12, and 24 weeks after the injection, all patients were asked to report their pain scores. The analgesic effect of the intra-articular injection peaked at 4 weeks and that of the intramuscular injection at 8 weeks.
The findings are important because previous research shows that 1 in 5 general practitioners do not consider themselves competent to administer a musculoskeletal injection. This leads to some patients being referred to the hospital for injection. Consequence: longer waiting time for the patient and higher costs for society.
That’s not the only drawback of intra-articular injection, explains Ph.D. student Qiuke Wang. ‘Intra-articular corticosteroid injections can cause cartilage loss, making osteoarthritis worse. In addition, it can cause an infection of the joint.’
It wasn’t just a subset of general practitioners who appeared to prefer a particular form of injection. Of the 145 patients, 18 percent preferred intra-articular injection, compared to 48 percent for intramuscular injection.
The researchers hope their results will spark conversation in the consulting room. ‘We are the first to show that both injections work well against pain. General practitioners and patients should come to the right choice together, based on the patient’s preferences and expectations, and the general practitioner’s skill level,’ concludes lead researcher Jos Runhaar.
In the infographic below, the researchers summarize their findings.