Steroid Injections for Arthritic Knees?

Summarized by Robert W. Griffith, MD
June 4, 2004

Introduction

People with osteoarthritis of the knee are always looking for effective therapy for the pain and disability this distressing condition produces. There is a natural reluctance to have injections into the knee joint, but two types of substances have been found to be effective when given this way - preparations of hyaluronic acid, and corticosteroids (or steroids). We have previously discussed hyaluronic acid here (see the first link below).

The effectiveness of steroids given this way is usually thought to be short-lived (2-4 weeks), and there is some anxiety that repeated use might lead to destruction of the joint (steroids tend to weaken connective tissue). However, two New Zealand researchers have examined published clinical studies and conducted a meta-analysis to try to reach definite conclusions about the long-term effectiveness and safety of steroid injections for knee osteoarthritis. They've published their findings in the British Medical Journal.

What was done

The researchers searched the medical literature for all published clinical studies of this treatment; the studies had to be 'randomized' and 'placebo-controlled', i.e. the patients had to be allocated by chance to receive intra-articular injections of a steroid drug or an inactive substance (salt solution).

'Improvement' was scored if one of the following terms was used to describe the changes produced by injections: distinct, subjective, or overall improvement, decreased pain, and clinically relevant outcome; in addition, response to an osteoarthritis symptom scale was used. This allowed the numbers of patients responding to either treatment (steroid or placebo) to be totaled for each study.

What was found

Ten clinical studies were found to be suitable for this analysis. Six of them showed significant improvement at two weeks after injection with the steroid, compared with the placebo. Not everyone getting the steroid improved. Statistical analysis determined that between one (actually, 1.3) and three to four (3.5) patients would need to be treated to achieve an improvement in one patient.

Two studies estimated improvement at 16 to 24 weeks after a single injection of 50 mg of the steroid prednisone. Taken together, the results showed a significant improvement with the steroid injections. Four to five (4.4) patients would have to be treated to ensure improvement in one patient at 24 weeks.

Only one study examined long-term safety with regard to the joint; there was no loss of joint space with either treatment (steroid or placebo) at two years.

What this means

This analysis has cleared up two apparent drawbacks in the use of intra-articular steroid injections for knee osteoarthritis. First, the beneficial effect can last for up to 24 weeks. Second, there's no evidence of joint deterioration months after the injection.

The numbers of patients studied in this way are not sufficient to be 100% sure of the long-term safety and effectiveness of corticosteroid use in this way. Moreover, only one patient out of 3 or 4 will be sure to be improved. However, these results are no worse than those for hyaluronic acid injections, and the procedure is certainly worth a trial in selected patients, before more drastic measures - e.g. knee replacement surgery - are contemplated.

Source

• Corticosteroid injections for osteoarthritis for the knee; meta-analysis. B. Arroll, F. Goodyear-Smith, BMJ, 2004, vol. 328, pp. 869--870

Related Links
A new Injection Treatment for Osteoarthritic Knees?
Knee Taping Helps Osteoarthritis Sufferers
Knee Osteoarthritis: Is Arthroscopy Any Help?

Please take a moment to give us your comments. For questions about Health matters you may check our "Questions & Answers" Portal and Service.