Common ground and continued debate: further response to “Strong evidence against PRP injections for chronic lateral epicondylar tendinopathy: a systematic review”

The rich academic discussion continues! Here is a Letter to the Editor from Renee Keijsers, Denise Eygendaal, Michel P. J. van den Bekerom that they wrote in response to a blog from RJ de Vos and colleagues (read it here), who wrote an initial Letter to the Editor (read it here) in response to: Robert-Jan de Vos, Johann Windt, Adam Weir. Strong evidence against platelet-rich plasma injections for chronic lateral epicondylar tendinopathy: a systematic review. Br J Sports Med. 2014;48(12):952-956.  Have something to add? Send us your thoughts or comment below!

LETTER TO THE EDITOR BY KEIJSERS, EYGENDAAL, AND VAN DEN BEKEROM

We thank RJ de Vos and colleagues for the response on our comments. We do agree that there is a lot of common ground between the two groups. This is probably the main reason for this lively discussion. The enthusiasm of the authors is reflected in both the original article as in the fast response to our comment.

The diagnostic terminology ‘tendinopathy’ is indeed substantively better than ‘epicondylitis’. The terms ‘lateral epicondylitis (LE)’, ‘lateral epicondylar tendinopathy’, ‘lateral epicondylalgia’ or ‘tennis elbow’ are often used interchangeably, where the same condition is meant. The Cochrane Library overcomes this by using the term lateral elbow pain; which is not an actual diagnosis, but only a description of the localization of the pain. The majority of cases are believed to be caused by a tendinous lesion of the common extensor tendon origin at the lateral epicondyle as a result of repetitive microtrauma. There are several hypotheses regarding the cause of the tendinosis in LE based on histopathological, biochemical and clinical findings. Cell apoptosis, angiofibroblastic features, or abnormal biochemical adaptations, largely suggesting that a failed healing response underlies the condition. (1,2)

We would also like to refine our criticism: we do agree that the design of the systematic review was performed correctly and with respect to the PRISMA guidelines. Nevertheless we think that the interpretations of these results are oversimplified. Due to the different techniques and the use of different concentrations of PRPs (with different platelet count, leukocyte concentration and activation of PRP) it is too hasty to definitively abort the use of PRPs. We do agree that a beneficial effect of PRPs (especially in relation to infiltration of whole autologous blood) in the treatment of LE has not been proven; therefore we need more placebo-controlled RCTs. Or to be more specific: we need more placebo controlled trials in which the technique is uniformly performed and controlled. We think that many of the infiltrations are not in the area of the ECRB tendon. When injection therapies are not performed in a standardized way by ultrasound guidance and with a well defined injection technique it is not possible to compare injection therapies with one another.

The authors state in their comment that ‘Comparison with autologous blood injections would only make sense if this would was “usual care” for tendinopathies’. A more recent review, than the one cited by the authors on the effect of different injectables in the treatment of LE, found a paucity of evidence from unbiased trials on which to base treatment recommendations for LE. However, this meta-analysis by Krogh et al. (2013) showed that injection therapy with autologous blood, PRP, hyaluronic acid and prolotherapy (injection with dextrose) were all more efficacious than placebo.(3) Therefore, we think there is still a place for injection therapy with autologous blood or (more expensive) PRP in the standard treatment of chronic tendinopathies of the elbow.

A hypothesis is that perforations of the affected tendon alone (without application of an injectable) could also have a therapeutic effect; the needle is used to either break up scars or poke holes in the injured tendon so that bleeding occurs. The blood cells carry precursors, which eventually develop into collagen to replace the damaged tendon. Therefore it is quite possible that all currently used injectables are not effective at all. As long as there is no consensus on the best treatment of LE, there will be many items to discuss about.

To our opinion the bottom-line should be that it is very important to remain critical about promising new developments in health care, and that results should be viewed in the right perspective.

References

1. Pitzer ME, Seidenberg PH, Bader DA. Elbow tendinopathy. Med Clin North Am. 2014 Jul;98(4):833-49.

2. Walz DM, Newman JS, Konin GP, Ross G. Epicondylitis: pathogenesis, imaging, and treatment. Radiographics. 2010;30:167-184.

3. Krogh TP, Bartels EM, Ellingsen T, Stengaard-Pedersen K, Buchbinder R, Fredberg U, Bliddal H, Christensen R. Comparative Effectiveness of Injection Therapies in Lateral Epicondylitis: A Systematic Review and Network Meta-analysis of Randomized Controlled Trials. Am J Sports Med 2013 Jun;41(6):1435-46

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