Corticosteroid injections ineffective for exercise pain in knee osteoarthritis

1. There was no significant difference in pain scores between groups that received corticosteroid intra-articular injections with exercise therapy and those who received placebo injections and exercise therapy.

Evidence Rating Level: 1 (Excellent)

Study Rundown: Osteoarthritis (OA) is a common and debilitating form of arthritis that may limit mobility and function of those with it. Exercise is recommended for OA of the knee, but one may be limited by pain. It is unclear if intra-articular injections of corticosteroids in combination with exercise synergistically provide clinical benefit for knee OA. This study aims to assess the clinical efficacy of intra-articular corticosteroid injections given before an exercise program in patients with knee OA as compared to placebo injections and exercise therapy.

There was no significant difference in pain scores between the corticosteroid and placebo groups. In addition, no significant difference was found between groups in any of the secondary outcomes. Strengths of this study include being a randomized, blinded placebo-controlled study and being the first to assess combined effects of corticosteroid injections and exercise. However, two considerable limitations include using a lower dose of corticosteroid than what is generally recommended for knee OA, and also using lidocaine in both injections across groups which may nullify any differences in pain control provided by the corticosteroid itself.

Click to read the study in JAMA Internal Medicine

Relevant Reading: Surgery versus physical therapy for a meniscal tear and osteoarthritis

In-Depth [randomized controlled trial]: This triple blinded, placebo-controlled trial was performed between October 2012 and April 2014 in Copenhagen, and randomized 100 patients from OA outpatient clinics to two groups: corticosteroid (methylprednisolone acetate 40 mg) dissolved in 4 mL lidocaine (10 mg/mL) with exercise and placebo (isotonic saline) dissolved in 4 mL lidocaine (10 mg/mL). The primary outcome was the change from baseline in the pain subscale of the Knee Injury and Osteoarthritis Outcome Score (KOOS) questionnaire at week 14. Using an intention-to-treat protocol, data was analyzed using repeated-measures mixed linear regression models.

There was no significant difference between the two intervention groups with respects to KOOS pain scores. The mean changes in the KOOS pain score at week 14 were 13.6 with standard error (SE) of 1.8 and 14.8 (SE 1.8) points in the corticosteroid and placebo groups. This corresponded to a mean difference of 1.2 points (95% CI, -3.8 to 6.2; p=0.64).

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