Is PRP bad for Achilles Tendinopathy? – Newcastle Podiatrist Blake explains

Newcastle Podiatrist reviews study

Is PRP effective for the treatment of Chronic Achilles Tendinopathy? - By our Newcastle Podiatrist Blake Withers

Now let’s talk about this study. We see this a lot here in our clinic in New Lambtom, Newcastle.

I think understanding the research on this topic gives you the ability to gain knowledge on this topic. I get asked this clinically (@ Achieve Podiatry in Newcastle) and by friends and family my opinion on if PRP is worth trialing both in the short and long term. Now firstly, we are talking about chronic Achilles Tendinopathy, not acute or not a case of a rupture.

What is PRP? PRP is defined as a platelet-rich concentrate with platelet levels greater than baseline when compared with whole blood. The mechanism is believed to be related to the actions of growth factors, including platelet-derived growth factor, transforming growth factor-b (TGF- b), and insulin-like growth factor, which may promote a healing responses

This is one of the first studies to pool data of RCT’s into a study. They wanted to answer one really important question.

Does PRP plus eccentric strength training result in

  1. Greater improvements in (VISA-A) scores
  2. Difference in Tendon thickness
  3. Differences in colour Doppler activity. I had not heard much about this but its when they measure the tendon looking at neovascularization. They think that if its increased initially after an injection and then decreases over time that it is beneficialcompared with placebo (saline) injections plus eccentric strength training?

At Achieve Podiatry Newcastle we consistently use strength training as a tool to get people out of pain and to improve their function.

The primary outcome was improvement in the VISA-A score, which ranges from 0 to 100 points, with higher scores representing increased activity and less pain. They considered the minimum clinically important difference on the VISA-A to be 12 points.

Four RCTs involving 170 participants were eligible and included 85 participants treated with PRP injection and eccentric training and 85 treated with saline injection and eccentric training.

Search statergy: Only RCT’s were included in the study. Good methods were used to reduce the risk of bias and to identify if bias was present in the included studies. Trials that compared PRP injection with saline injection for chronic Achilles tendinopathy; and (4) VISA- A score, tendon thickness change, color Doppler activity, and other functional measures (eg, pain and return to sports activity) were included.

Results:

  1. They found no difference between the PRP and saline groups regarding the primary outcome (VISA-A score: mean difference [MD] = 5.3; 95% CI, -0.7 to 11.3; p = 0.085.
  2. They found no difference between the PRP and saline groups in terms of ultrasonographic evaluation of tendon thickness; the mean difference between the PRP and saline groups in tendon thickness change was 0.2 mm (95% CI, -0.6 to 1.0 mm; p = 0.663;).
  3. They found no difference between the PRP and saline groups in terms of color Doppler activity (MD = 0.1; 95% CI, -0.7 to 0.4; p = 0.695; Fig. 5).
  4. One study reported that at 6 month follow up, the PRP group did report less pain.
  5. There was no difference in people returning to their primary sport between groups.
  6. They did find one study reported statistically signifgicant VISA-A improvements at 2 weeks following PPP injections. They summarised that repetition of injections may prolong the exposure of growth factors to the tendons and thereby improve the result.

Discussion/Problems: There were 170 participants included between 4 studies. This number is significant, but low. Their power calculation however did confirm they had 80% power to detect a 12 point different in the VISA-A. For a statistically significant effect, a 12 point difference had to be identiiided, other studies have ranged from 6.5 to 16. Its possible it was to high to detect change when there was change, it just didn’t sit above the 12 number. This study was done with people from the general population, not elite athletes which makes it not as relatable to athletes. The follow up time was 3-12 months. They report it they could of used a longer time frame, however, effects of PRP are mostly lost after that time.

The authors summary and a Podiatrist Perspective:

In conclusion, PRP injection with eccentric training did not improve VISA-A scores, reduce tendon thickness, or reduce colour Doppler activity for chronic Achilles tendinopathy when compared with saline injection with eccentric training with sufficient statistical power analysis. However, our conclusions are based on only four RCTs with relatively small sample sizes. Larger randomised trials are needed to confirm these results, but until or unless a clear benefit has been demonstrated in favour of the new treatment, we cannot recommend it for general use

What does this mean? Let our Newcastle Podiatrist explain

  1. PRP may be an option before surgery as a last resort (maybe).
  2. Anybody who has been recommended PRP should be informed there isn’t just poor evidence, there seem to no evidence to support its use.
  3. Allied health (all Newcastle Podiatrists) should be education patients on the implications of injections (e-g, risk of adverse reactions and cost)
  4. Strength training, shockwave, load modification, heel lifts, footwear are all treatments that should be exhausted before the thought of PRP.