Both intra-articular glucocorticoid injections and physical therapy can improve symptoms in patients with knee osteoarthritis however the non-invasive intervention has been shown to be superior in a recent study.

The US study of patients in the Military Health System comprised 156 men and women with a median age of 56 years and confirmed OA, mostly Kellgren-Lawrence grade 2 and 3.

Patients received a mean of three injections of 1 ml of triamcinolone acetonide during the 12-month study period or 12 sessions of hands-on passive joint mobilisation and muscle stretching plus instruction for home exercise.

The study found WOMAC scores decreased significantly in both groups – from 108.8 at baseline to 55.8 in the injected group and from 107.1 to 37.0 in the physical therapy group.

The proportion of patients who did not improve was higher in the injected group than the physical therapy group (25.6% v 10.3%).

There was only one adverse event recorded – a patient who fainted during the glucocorticoid injection.

The mean cost for all knee-related medical care was similar in both groups ($2,113 v $2,131).

“The results of our trial are consistent with those of previous trials, which suggests that the short-term improvement expected with glucocorticoid injection can also be seen with physical therapy; however, treatment effects of physical therapy persist for a year,” the study said.

However the authors admitted that glucocorticoid injections were used more frequently in clinical practice than physical therapy.

An accompanying editorial in the NEJM said injections had the advantage of being easy to administer, requiring fewer visits and therefore had less issues with compliance.

However the Australian authors, Professor Kim Bennell and Professor David Hunter, said injections also had the potential for adverse events.

“The results do not exclude a role for joint injection for treatment of a flare of acute pain, as acknowledged in guideline recommendations, but the implication could be that injections should not be used first, nor should they be used in place of a physical therapy program that includes exercise to manage symptoms of osteoarthritis of the knee.”

“Challenges remain as to how to change the referral behaviour and treatment decisions of clinicians and how to provide health service models that offer nondrug and nonsurgical approaches in the treatment of patients with osteoarthritis of the knee,” they said.