Injections for Tendon Pain
Tendinopathy (tendon pain) is very common. They are the most common type of overuse injury (ref). Achilles tendinopathy affects the majority of runners (ref) and is the reason 16% of athletes have to stop sports participation (ref).
There are a range of commonly prescribed treatment options for tendinopathy, but very few are supported by quality, randomised, prospective, placebo-controlled trials.
SO WHAT DO I DO?
Considering all the available treatment options, above anything else, I always recommend:
WHAT ABOUT INJECTIONS?
Having mapped out a management plan, patients will routinely ask my opinion on getting an injection. They may have had a friend for whom an injection worked well, or the GP has suggested it as an option, or they’ve had one before and it worked.
There are a range of drugs to inject into or around a tendon, depending on who you are referred to:
Corticosteroids are an anti-inflammatory medication injected around the tendon to decrease pain that is caused by inflammation (although it is now thought that inflammation does not play a significant role in tendon pain). Corticosteroid injections have historically been commonly prescribed but more recently their use is controversial. Repeated corticosteroid injections can weaken the tendon and increase the risk of rupture. Corticosteroid injections are good at relieving pain in the short term (2-6 weeks) however, there is strong evidence that long-term outcomes (> 6 months) are worse than other conservative treatments or no treatment at all (ref).
PROLOTHERAPY / SCLEROTHERAPY
Prolotherapy injections act as an irritant causing an inflammatory response then scarring of the nerves that transmit pain. There is no solid support in the medical literature for this procedure for the treatment of tendinopathies. A randomised controlled trial of polidocanol injections showed the potential to reduce tendon pain in patients with chronic painful mid-portion Achilles tendinopathy (ref). However, a systematic review found limited results for use of prolotherapy in sports related soft tissue injuries (ref).
AUTOLOGOUS BLOOD INJECTIONS
The rationale of autologous blood injection consists of enhancing tendon healing through collagen regeneration and the provision of cellular mediators. Good experimental models are lacking, and clinical application is anecdotal. A 2013 randomised controlled trial investigating the efficacy of autologous blood injections as a treatment for mid-portion Achilles tendinopathy concluded they did not reduce pain or improve function any more than a strengthening program. (ref)
The suggested mechanism of high-volume injections is the mechanical disruption of local tissues then stimulates a healing response. One study (ref) has shown that high-volume injection of normal saline solution, corticosteroids or anaesthetics reduces pain and improves short and long-term function in patients with Achilles tendinopathy. However, more research is required.
PLATELET RICH PLASMA (PRP)
Platelets are naturally occurring in your blood, where they play an important role in healing damaged tissue, so superficially it’s inherently appealing to just add more of them to the sore spot. PRP injections are particularly trendy at the moment and it’s easy to find someone who will tell you they work well. Unfortunately, research concludes there is no benefit to PRP injections. This study found PRP injections do not improve plantar fasciopathy pain or function. This study concluded there is insufficient evidence to support the use of PRP for treating musculoskeletal soft tissue injuries. This systematic review found strong evidence against platelet-rich plasma injections for tennis elbow. This study found PRP did not improve tendon structure. This meta-analysis found no greater clinical benefit of PRP over placebo or dry needling for tendinopathy.
Would I have any of these injections, or would I recommend them to my patients, friends, or family? Well it depends. In my experience some people get some benefit some of the time. HOWEVER, these injectables are not consistently effective and their use is mostly not supported by research. I suggest that patients try the strengthening program and the results will be overall better in the long term.
WHY DO THE INJECTIONS WORK FOR SOME PEOPLE?
I’ve been frustrated with a couple of patients that cancelled their follow-up appointment and, when I phoned and asked what had happened, they’ve had an injection and now feel fine. My conclusion is the injections don’t work, but if you were sore and now you’re not, your conclusion would be they do work. So what is it?..
REGRESSION TO THE MEAN
Most people seek treatment when they are at their worst. By definition the only possible change from being as bad as at can be, is an improvement. Was it the injection working, or was it getting better anyway?
Some conditions are self limiting and will just get better by themselves. Did the injection work, or was it about to get better anyway?
I understand that getting an injection seems like a much easier option than doing 12-weeks of strengthening exercises, but in the long run, a strengthening program is the thing that actually works.
If treating tendon pain was as easy as getting an injection then that’s what everyone would do first. Unfortunately it’s not as easy as that.
Have you had an injection for your tendon?
Tendon pain is the most common gradual-onset, overloading injury. Mechanotherapy / exercise is the most beneficial treatment option.
Eccentric exercises have been commonly prescribed over the last decade, following the pain-provoking Alfredson programme of 3 x 15 reps, twice/day. It sometimes works very well.
The last few years I’ve favoured isometric exercise as an initial treatment - partly because of personal experience with Achilles, patellar, and lateral elbow tendon issues, & recommendation from Jill Cook & Craig Purdham at the AIS.
New research adds some support to isometric exercise as a treatment for tendinopathy, concluding it reduces tendon pain and improves strength. The authors delve in to all the “hows” & “whys” of how it works in their discussion, and to be honest it’s a bit technical for my understanding.
The research protocol uses 5 reps of a 45 second contraction, at a 70% effort. I prefer a more gentle contraction of 50% effort, but a longer hold of at least a minute, and I like a larger total volume of at least 10 minutes/day. Obviously it’s hard to define what the perfect dosage is for exercise, & volume could be adjusted depending on results.
I like isometrics because: