To assess the effectiveness of extracorporeal shockwave therapy (ESWT) in the treatment of plantar fasciitis, and to provide a comprehensive survey of trials published in English or German with a biometrically sound evaluation.

MEDLINE (via PubMed, August 2000 ) and the Cochrane Library (Issue 4, 2000) were searched for English or German publications using the terms 'fasciitis', 'heel', shock', 'shock-wave' and 'ESWT'. In addition, the German journal 'Orthopadische Praxis' was handsearched from 1988, as were the reference lists from all identified articles.

Study designs of evaluations included in the review

No study designs were excluded, other than those that did not reportan outcome. Review articles and studies only available as abstracts were excluded.

Specific interventions included in the review

Studies using ESWT were included. Most studies reported 1 to 3 treatments, although 3 studies reported more than 3 treatments. Details of the frequency of ESWT, number of impulses and reported energy used were provided, although the authors cautioned that the reported energy may not accurately reflect the actual energy used. Six studies reported the use of anaesthesia and 6 reported no use; 5 studies did not mention whether or not it was used.

Participants included in the review

Studies of patients being treated for heel spur or plantar fasciitis were included. The patients in the included studies had suffered from the condition for at least 2 months, and for over one year in the majority of studies. Of the 14 studies reporting age data, 13 studies reported a mean age between 44 and 55 years.

Outcomes assessed in the review

No inclusion criteria for the outcomes were specified. The outcomes assessed included measures of pain, a visual analogue scale (VAS) score and subjective improvement.

How were decisions on the relevance of primary studies made?

The authors do not state how the papers were selected for the review, or how many of the reviewers performed the selection.

Standard criteria extracted from European guidelines on good clinical practice and on statistical principles in clinical trials were used to evaluate the studies (see Other Publications of Related Interest nos.1-2). These criteria were related to control groups, randomisation, inclusion point, relevant end points, appropriate sample size, blinding, prognostic factors, completeness of follow-up, adequate data analysis, and intention to treat analysis. One reviewer carried out the validity assessments, and a second reviewer checked them. Consensus was reached by discussion.

The authors do not state how the data were extracted for the review, or how many of the reviewers performed the data extraction. The data extracted included: sample size; duration of symptoms; age; gender; device used; the number and frequency of the treatments; the number of impulses and the reported energy; the use of anaesthesia; end point; and follow-up. Details of the validity assessment were also reported.

How were the studies combined?

The studies were not combined.

How were differences between studies investigated?

Differences between the studies were only investigated in terms of the methodological quality.

Seventeen studies were included. There were 3 blinded randomised controlled trials (RCTs) with a placebo treatment control group. One non-blind RCT and 2 quasi-randomised controlled trials compared 2 different modalities of ESWT. There were 11 uncontrolled trials.

None of the trials fulfilled all the methodological criteria for the conduct of therapeutic trials, as laid down in the international guidelines used. The three placebo-controlled RCTs found an improvement in 67% of the treated patients versus 27% of the placebo-treated patients after 6 weeks (n=30). Improvements were also shown in 56% (treated) versus 16% (untreated) of the patients after 12 weeks (n=100), and in 88% (treated) versus 34% (untreated) of the patients after 1 year (n=100). The results of the other trials were not reported.

The studies of Rompe et al. (references provided) give preliminary evidence for the effectiveness of ESWT for plantar fasciitis but, because of the methodological problems inherent in all of the evaluated studies, its effectiveness can be neither confirmed nor excluded on the basis of the available data. Clinical studies that adhere to the biometrical principles for the conduct of clinical trials are proposed.

The review question and the inclusion criteria were clear, except for study design. No study design criteria were initially defined, but the review effectively restricted itself to double-blinded randomised placebo-controlled trials, which also met other quality criteria through the application of a very rigorous quality assessment. The authors reported considerable details on the participants, treatments and conduct of the 14 studies that did not fulfil these criteria, but did not report their results.

The search strategy was good and included German articles, as many studies have apparently been conducted in Germany. No details of the study selection and data extraction processes were included, so it is impossible to judge whether these were adequate to guard against errors. The validity assessments were checked by a second reviewer.

Basic results from the three placebo-controlled RCTs were mentioned in the 'Discussion' section. However, the authors neither reported nor undertook any statistical analysis of the results, and so the statistical significance of the results could not be assessed. Whilst the authors are correct to point out that confidence intervals provide more information than statistical significance alone, a test of significance with an associated p-value would, nevertheless, have conveyed useful information. These three studies were rated as having inadequate evidence on the grounds that there were no details of the randomisation process and that, even where the investigators were blinded, the patients might not have been (although this would not have be a common scenario). The studies were also criticised for not reporting power calculations, confidence intervals and details of prognostic factors. Whilst all these considerations are certainly worthy of note in assessing study validity, it is the opinion of this reviewer that the results of such trials, although certainly not of the highest quality, should be fully reported to be more informative. The authors' conclusions appear to be justified, but more details of the trials constituting the 'preliminary evidence' would have been helpful.

Practice: The authors did not state any implications for practice.

Research: The authors state that clinical studies that adhere to biometrical principles for the conduct of clinical trials are required to adequately estimate the value of ESWT as a treatment for plantar fasciitis. In view of the authors' conclusions regarding the inadequacy of the current research, it would appear that these particular shortcomings should be addressed in future research.

1. The European Agency for the Evaluation of Medicinal Products Human Medicines Evaluation Unit. ICH Topic E 6. Guideline for good clinical practice. CPMP/ICH/135/95. 1996. Available from: http://www.ema.europa.eu/docs/en_ GB/document_ library/Scientific_ guideline/2009/09/WC500002874.pdf [accessed 24/07/2014].

2. The European Agency for the Evaluation of Medicinal Products Human Medicines Evaluation Unit. ICH Topic E 9. Guideline for statistical principles in clinical trials, CPMP/ICH/363/96E9. 1998. Available from: http://www.ema.europa.eu/ema/index.jsp?curl=pages/regulation/general/general_ content_ 000429.jsp& amp;mid=WC0b01ac0580029590 [accessed 24/07/2014].

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.