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Am Fam Physician. 2005;72(7):1222-1224

Clinical Scenario

A 60-year-old woman with osteoarthritis of her right knee has pain and swelling despite daily use of nonsteroidal anti-inflammatory drugs (NSAIDs).

Clinical Question

Would this patient benefit from an intra-articular injection of a corticosteroid?

Evidence-Based Answer

An injection of the knee joint with a corticosteroid may improve the patient’s symptoms for up to three weeks after the injection (number needed to treat [NNT]= 3 to 4). There is no evidence that this intervention improves function, and there is little evidence of the benefits persisting beyond three weeks. Risk of dangerous adverse effects is minimal. Injection of hyaluronan and hylan products (Hyalgan, Orthovisc, Synvisc) may provide longer-lasting benefit.

Practice Pointers

This review1 shows that intra-articular injection of a corticosteroid is useful in improving pain and the patient’s global assessment of symptoms for up to three weeks in patients with osteoarthritis of the knee. The analysis was based on 26 trials with a total of 1,721 patients. However, most studies were small and brief, with fewer than 100 participants and a duration of less than 26 weeks. Only good-quality studies that used standardized rheumatologic outcome measures were included in the review. The authors made an adequate attempt to find all relevant articles and combined data using standard techniques.

There are many effective treatments available for mild symptomatic osteoarthritis, including patient education, physical and occupational therapy, oral and topical analgesics, and NSAIDs.24 Nonetheless, many patients still suffer from pain and reduced function despite treatment efforts. Since the 1950s, patients have been given intra-articular corticosteroid injections when other nonsurgical therapies are inadequate. This review did not find strong evidence to support the use of one particular corticosteroid preparation, dose, injection technique, or frequency of injection, but triamcinolone hexacetonide (Aristospan) was superior to betamethasone (Celestone) in the number of patients reporting pain relief at four weeks. The reviewers also found no particular indication (e.g., joint effusion) that would help select patients who are more likely to benefit.

The same authors published a separate review5 of injection with hyaluronan and hylan derivatives for osteoarthritis of the knee, in which they found this treatment to be effective. The Cochrane Collaboration has elsewhere reviewed corticosteroid injections for shoulder pain,6 finding weak evidence for a small and short-lived benefit in rotator cuff disease and adhesive capsulitis. The collaboration also has reviewed local injection of corticosteroid for carpal tunnel syndrome7 and found benefit lasting up to one month. Some evidence-based clinical guidelines2,4 recommend intra-articular corticosteroid injection for treatment of osteoarthritis of the knee when other, more conservative, treatments are not effective. Several authors have described injection techniques in detail.810 This Cochrane review covers the best and most recent evidence available and supports the use of intra-articular corticosteroids for osteoarthritis of the knee.

Cochrane Abstract

Background. Osteoarthritis is a common joint disorder. In the knee, injections of corticosteroids into the joint (intra-articular) may relieve inflammation and reduce pain and disability.

Objectives. To evaluate the efficacy and safety of intra-articular corticosteroids in treatment of osteoarthritis of the knee.

Search Strategy. The authors1 searched the Cochrane Central Register of Controlled Trials (CENTRAL) (Issue 2, 2003), MEDLINE, EMBASE, PREMEDLINE (all to July 2003), and Current Contents (Sept 2000). Specialized journals, trial reference lists, and review articles were hand-searched.

Selection Criteria. Randomized controlled trials of intra-articular corticosteroids for patients with osteoarthritis of the knee: single- or double-blind, placebo-based, or comparative studies reporting at least one core OMERACT III outcome measure.

Data Collection and Analysis. Methodologic quality of trials was assessed, and data were extracted in duplicate. Fixed-effect and random-effects models, giving weighted mean differences (WMDs), were used for continuous variables. Dichotomous outcomes were analyzed by relative risk (RR).

Primary Results. Twenty-six trials (1,721 participants) comparing intra-articular corticosteroid against placebo, against intra-articular hyaluronan/hylan (HA) products, against joint lavage, and against other intra-articular corticosteroids, were included.

Intra-articular corticosteroid was more effective than intra-articular placebo for pain reduction (WMD: −17.79; 95% confidence interval [CI], −25.02 to −10.55) and patient global assessment (RR: 1.44; 95% CI, 1.13 to 1.82) at one week postinjection with an NNT of 3 to 4 for both, based on n = 185 for pain on a 100-mm visual analogue scale (VAS) and n = 158 for patient global assessment. Data on function were sparse at one week postinjection, and neither statistically significant nor clinically important differences were detected.

There was evidence of pain reduction for two (RR: 1.81; 95% CI, 1.09 to 3.00) to three weeks (RR: 3.11; 95% CI, 1.61 to 6.01) but a lack of evidence for efficacy in functional improvement.

At four to 24 weeks postinjection, there was a lack of evidence of effect on pain and function (small studies showed benefits that did not reach statistical or clinical importance, i.e., less than 20 percent risk difference. For patient global assessment, there were three studies that consistently showed lack of effect longer than one week postinjection. However, all were fairly small sample sizes (fewer than 50 patients per group). This result was supported by another study that did not find statistically significant differences, at any time point, on a continuous measure of patient global assessment (100-mm VAS).

In comparisons of corticosteroids and HA products, no statistically significant differences were detected in general at one to four weeks postinjection. Between five and 13 weeks postinjection, HA products were more effective than corticosteroids for one or more of the following variables: WOMAC osteoarthritis Index, Lequesne Index, pain, range of motion (flexion), and number of responders. One study showed a difference in function between 14 and 26 weeks, but no differences in efficacy were detected at 45 to 52 weeks. In general, the onset of effect was similar with intra-articular corticosteroids but was less durable than with HA products.

Comparisons of intra-articular corticosteroids showed triamcinolone hexacetonide was superior to betamethasone in the number of patients reporting pain reduction up to four weeks postinjection (RR: 2.00; 95% CI, 1.10 to 3.63). Comparisons between intra-articular corticosteroid and joint lavage showed no differences in any of the efficacy or safety outcome measures.

Reviewers’ Conclusions. The short-term benefit of intra-articular corticosteroids in treatment of knee osteoarthritis is well established, and few side effects have been reported. Longer-term benefits have not been confirmed based on the RevMan analysis. The response to HA products appears more durable. In this review, some discrepancies were observed between the RevMan 4.1 analysis and the original publication. These likely are the result of using secondary rather than primary data and of the statistical methods available in RevMan 4.1. Future trials should have standardized outcome measures and assessment times, run longer, examine different patient subgroups, and investigate clinical predictors of response (e.g., those associated with inflammation and structural damage).

These summaries have been derived from Cochrane reviews published in the Cochrane Database of Systematic Reviews in the Cochrane Library. Their content has, as far as possible, been checked with the authors of the original reviews, but the summaries should not be regarded as an official product of the Cochrane Collaboration; minor editing changes have been made to the text (http://www.cochrane.org).

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