New research on injections for osteoarthritic knees.

A loss of articular cartilage and hyaluronic acid, a naturally occurring lubricant in the knee, are characteristic of knee osteoarthritis. Previous research has shown that restoring a lubricating fluid into the knee by injection significantly improves the debilitating symptoms of osteoarthritis (see Running & FitNews, February 2001). Illustrating just how confusing and contentious medical research can be, recent reports published in the Archives of Internal Medicine both support and question the efficacy of the treatment.

In this study, 120 patients were randomly divided into four groups, each receiving a pill (either non-steroidal anti-inflammatory drug (NSAID) or placebo) and an injection (either hyaluronate sodium or saline placebo).The injections were repeated once a week for three weeks and the pills were continued over 12 weeks. Measures of pain, stiffness, disability and functional performance (exercise time, heart rate and oxygen uptake) were made at baseline, at four weeks and at 12 weeks. The authors concluded that hyaluronate sodium was as effective as NSAIDs for pain at rest, and superior for pain with exercise, resulting in improved physical performance.

The editors of the Archives, however, were not as impressed with the study results as the authors were. In an editorial in the same issue, they conclude that the data did not provide the statistical evidence needed to support the claims made. In fact, the journal's editors saw no evidence to suggest that the hyaluronate sodium injections were superior to placebo. According to these editors, while there is good reason to think this approach to treatment might produce benefits, a broader review of the literature shows no measurable effects in any well-designed, large studies. While the jury is still out, many physicians are having success with the treatment. Make sure to discuss your treatment options with your doctor.

(Archives of Internal Medicine, 2002, Vol. 162, No. 3, pp. 292-298; pp. 245-247)