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Corticosteroid injections for lateral epicondylitis: a systematic review |
Smidt N, Assendelft W J, van der Windt D A, Hay E M, Buchbinder R, Bouter L M |
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Authors' objectives To evaluate the effectiveness of corticosteroid injections for lateral epicondylitis.
Searching MEDLINE, EMBASE and CINAHL were searched from inception to July 1999, with an additional search for systematic reviews being conducted in EMBASE and MEDLINE. The Cochrane Controlled Trials Register (Issue 2, 1999), Current Contents (July 1999) and the Cochrane Rehabilitation and Related Therapies Field's trials register were also searched. The references from retrieved articles were screened for additional relevant studies. Only studies where the full report was published before July 1999 were eligible for inclusion in the review.
Study selection Study designs of evaluations included in the reviewRandomised controlled trials (RCTs) were eligible for inclusion in the review.
Specific interventions included in the reviewComparisons of corticosteroid injection treatment with a control intervention of no treatment, placebo, local anaesthetic, other corticosteroid injection or other conservative treatment were eligible for inclusion in the review. The types and dosages of corticosteroid injection varied between the studies; further details were provided.
Participants included in the reviewPatients with a clinical diagnosis of lateral epicondylitis, or lateral elbow pain that was increased by pressure on the lateral epicondyle and during resisted dorsiflexion of the wrist, were eligible for inclusion in the review. The patients in the included studies had acute, subacute or chronic lateral epicondylitis.
Outcomes assessed in the reviewStudies assessing pain, global improvement, elbow-specific functional status, grip strength or sick leave were eligible for inclusion in the review. The outcomes assessed in the review were pain, global improvement and grip strength in the short term (6 weeks or less) and intermediate and long term (over 6 weeks).
How were decisions on the relevance of primary studies made?Two reviewers independently read the abstracts of all identified studies to assess their relevance for the review. In cases where there was any doubt, the full article was retrieved, blinded for author, journal and year of trial, and independently read by two reviewers. Any disagreements were discussed and resolved in a consensus meeting. For studies published in languages other than English, German or Dutch, a native speaker or translator with content expertise assisted in assessing the studies' relevance for the review.
Assessment of study quality The quality of the included studies was assessed using the Amsterdam-Maastricht consensus list and the Jadad scale. Two reviewers independently assessed the included studies for quality. The studies were blinded for author, journal and year of trial. The overall disagreement was assessed and expressed as a percentage of agreement and kappa statistics. Any disagreements were discussed and resolved in a consensus meeting. Where disagreements remained, a third reviewer made the final decision.
Data extraction Two reviewers independently extracted the data from the included studies. The studies were blinded for author, journal and year of trial. For studies published in languages other than English, German or Dutch, a native speaker or translator with content expertise assisted in the data extraction.
Data were extracted on the following: intervention, timing of outcome assessment, adverse effects, loss to follow-up and results. The results of the included studies were expressed as relative risks with 95% confidence intervals (CIs) for dichotomous data, and as standardised mean differences with 95% CIs for continuous data.
The studies were weighted according to internal validity, statistical significance, clinical relevance and power, and the evidence was classified as 'strong', 'weak' or 'insufficient'.
Methods of synthesis How were the studies combined?Clinically and statistically homogeneous studies with acceptable internal validity (score of 7 or more) were pooled using a random-effects model. The studies were classed as clinically homogeneous if they were comparable in terms of the timing of the outcome assessment, follow-up, control group and outcome measure.
Where statistical pooling was not appropriate, conclusions about the strength of the evidence were based on the consistency of findings between individual studies. Findings were considered to be consistent if more than 75% of the studies reported similar results for the same outcome measure.
Publication bias was assessed using a funnel plot.
How were differences between studies investigated?Statistical heterogeneity was assessed using the chi-squared test.
Results of the review Thirteen RCTs, with 15 comparisons and a total of 1,028 participants, were included in the review.
For short-term assessments (6 weeks or less), 13 of the 14 comparisons found statistically-significant and clinically-relevant short-term results in favour of corticosteroid injections in terms of pain or global improvement. For intermediate and long-term effectiveness, no comparisons found statistically-significant intermediate (6 weeks to 6 months) or long-term (6 months or more) outcomes in favour of corticosteroid injections. The only study that found statistically-significant and clinically-relevant results was in favour of non-steroidal anti-inflammatory drugs at 6 months' follow-up.
Overall, there was insufficient evidence to either support or refute the effectiveness of corticosteroid injections compared with placebo, local anaesthetic or other conservative treatments, due to the low internal validity scores (mean 3.9, standard deviation 2.0). Only one study had an acceptable internal validity score of 7 or more.
Eight studies reported data on adverse effects. Four studies reported post-injection pain (11 to 58%) and local skin atrophy (17.40%); this was irrespective of whether the participants received corticosteroid injection or control treatment. One study reported facial flushes as an adverse effect of corticosteroid injection.
The overall inter-rater agreement was 83% (kappa statistic 0.62) on the internal validity items of the quality assessment.
The authors stated that the funnel plot for assessing publication bias was symmetrical; however, the data were not shown.
Authors' conclusions Corticosteroid injections seemed to be effective in the short term. Additional well-designed trials with long-term follow-up are needed to provide evidence on the beneficial and adverse long-term effects of corticosteroid injections.
CRD commentary The research question and the inclusion criteria were well defined. The search strategy for published studies was adequate. Unpublished studies were not sought, which may allow the introduction of publication bias. However, a funnel plot found no evidence of publication bias.
Two reviewers independently and blindly assessed the studies for inclusion and carried out the quality assessment and data extraction. This reduces the chances of error and bias. Sufficient detail was presented for all included studies. The studies were systematically assessed for inter-rater agreement and validity, and the results of this were used in the review. The authors assessed heterogeneity and the synthesis of the results appears to have been appropriate.
The authors presented the results of all studies, irrespective of their quality score, and the overall conclusion was based on these findings. The authors did, however, emphasise the lack of evidence these poor-quality studies represent.
Implications of the review for practice and research Practice: The authors did not state any implications for practice.
Research: The authors stated that there is a need for good-quality RCTs of sufficient size to investigate the short-, intermediate- and long-term effects of corticosteroid injections for lateral epicondylitis, using standardised outcome measures. They also stated that more research is needed to investigate the late possible adverse outcomes of corticosteroid injections at long-term follow-up in comparison with other conservative treatments.
Bibliographic details Smidt N, Assendelft W J, van der Windt D A, Hay E M, Buchbinder R, Bouter L M. Corticosteroid injections for lateral epicondylitis: a systematic review. Pain 2002; 96(1-2): 23-40 Indexing Status Subject indexing assigned by NLM MeSH Adrenal Cortex Hormones /administration & Humans; Randomized Controlled Trials as Topic; Tennis Elbow /drug therapy; dosage AccessionNumber 12002001316 Date bibliographic record published 30/06/2004 Date abstract record published 30/06/2004 Record Status This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn. |
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