THE INJECTION SERIES:
I'm often asked whether it’s useful to get an injection for Achilles tendonitis; does it not just mask the pain? The answer depends on what type of injection we’re talking about and what else you’re doing to relieve your Achilles pain. Remember, if you need help with an Achilles injury, you're welcome to consult one of our team via video call.
The terms tendinitis, tendonitis, tendinosis, and tendinopathy mean the same thing for all practical purposes, and we use these interchangeably in most of our articles.
In this article:
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Types of injection for Achilles tendonitis
First, an overview of the main types of injection for Achilles tendonitis that are prescribed – rightly or wrongly. We have articles with more detail on each of these, and the links are below.
PRP
PRP stands for “platelet-rich plasma”. This is where they draw some blood from the patient, separate out the blood plasma and platelets, and then inject that plasma into the injured tendon.
The plasma has a high concentration of blood platelets, and these platelets are thought to stimulate the production of collagen, which is the stuff that tendons are mainly made of. The thinking is that this will speed up the healing process in the tendon. It can also dull pain.
Does it work for Achilles tendonitis? The jury is still out. It has been shown to work for other types of tendon injury, such as tennis elbow and patellar tendinopathy. However, initial studies on Achilles tendonitis seem to indicate either that it has no benefit, or the studies produced conflicting results, indicating that the PRP techniques for Achilles tendonitis may have to be refined some more. More research needs to be done.
Read more about PRP injections for Achilles tendinopathy.
High-volume injections
This is where they inject a lot of sterile saline water into the tendon, and they do a little bit of movement with the hypodermic needle.
High-volume injections are really useful for dulling the pain down, so if you've got a super painful Achilles tendon, one of these can help to just bring your pain down a little bit.
Researchers aren’t sure yet why this works. An injured tendon has little blood vessels growing into it that aren’t there in a healthy tendon, and each of these blood vessels has a nerve ending. Some think that a high-volume injection collapses some of the blood vessels, which also gets rid of their nerve endings, which means less pain in the tendon.
Read more about high-volume injections as treatment for Achilles tendinopathy.
Hyaluronic acid
Hyaluronic acid occurs naturally in our joints; its purpose is to reduce friction. Synthesised hyaluronic acid is sometimes injected into painful joints to relieve the pain, e.g. when someone has arthritis in their knee.
The recent thinking with tendons has been that some of the pain in an injured tendon might be caused by the friction between the tendon and the sheath that envelops it, and that hyaluronic acid could help to reduce this friction. Initial studies to confirm this hypothesis have produced promising results, but yet again, more research is needed.
Read more about hyaluronic acid for Achilles tendon pain.
Steroids – Avoid!
Steroids (also called corticosteroids) should never be used for Achilles tendons. Research has found that steroids can cause a degradation of your tendons, so that an injured tendon becomes even weaker, which can create further problems down the line.
Steroids are brilliant at killing pain, and that's why they've been used traditionally for Achilles tendonitis, but nowadays doctors should really not be injecting steroids into tendons. (The same goes for steroid tablets and capsules.)
Read more about why corticosteroid injections may not be a good treatment option for Achilles tendinopathy.
An injection for Achilles tendonitis is not a silver bullet
It would be a big mistake to get an injection for Achilles pain and then go, “Well, I’ll go back to running and playing sports in two weeks’ time because I feel perfect now!”
An injection for Achilles pain should never be used in isolation, because it only manages the pain (if it’s the right type and if it’s done right). No injection has been shown to heal an Achilles tendon or even speed up the healing process.
An injured tendon is not as strong as a healthy tendon, and the only way to get it to withstand your normal daily activities and sport without getting painful time and again is to strengthen it back up with exercises. This takes a minimum of 12 weeks.
So, the best treatment for Achilles tendon injuries – and this is supported by research – is a combination of relative rest where you avoid or adapt exercises and daily activities that cause you a lot of pain, and an exercise programme for your tendon to restore its strength.
You have to start the exercises at the right level of difficulty for your tendon and then increase the difficulty to keep pace with how your tendon recovers. An experienced physiotherapist will be able to assess your injury and design a personalised Achilles rehab programme for you.
When to relieve your Achilles pain with an injection
First, we need to understand that the amount of pain and the severity of the injury do not always correlate. Often, an injury that is not very severe or that has healed remains painful, and other times an injury can be quite severe without causing the patient much pain.
This means that sometimes a patient’s injured tendon is strong enough for them to get on with their rehab exercises, but it is so painful that they just can’t do the exercises. In those cases, it may be useful to do something like a high-volume injection just to get that pain response to reset back to normal and see whether the injured tendon can then handle the exercises.
So, if you're finding it hard to get going with your rehab due to severe pain and you're sure that you're on the right rehab programme for you, or your Achilles tendon just stays super painful and despite your doing everything right it's just not progressing, an injection may be useful.
If you can progress with your rehab programme without too much pain, it would be better if you can get away with not having an injection, because these injections don’t work for everyone, and they have side effects. However, if you have been following a proper rehab programme for at least 12 weeks and the pain persists, you could consider getting an injection to see whether that helps.
How we can help
Need help with your Achilles injury? You’re welcome to consult one of the team at TMA online via video call for an assessment of your injury and a tailored treatment plan.
We're all UK Chartered Physiotherapists with Master’s Degrees related to Sports & Exercise Medicine. But at Treat My Achilles we don't just value qualifications; all of us also have a wealth of experience working with athletes across a broad variety of sports, ranging from recreationally active people to professional athletes. You can meet the team here.
About the Author
Maryke Louw is a chartered physiotherapist with more than 15 years' experience and a Master's Degree in Sports Injury Management. Follow her on LinkedIn and ResearchGate.
References
Le, A. D., et al. (2019). "Platelet-rich plasma." Clinics in Sports Medicine 38(1): 17-44.
Frizziero, A., et al. Efficacy of ultrasound-guided hyaluronic acid injections in achilles and patellar tendinopathies: a prospective multicentric clinical trial. Muscles, Ligaments & Tendons Journal 9(3), 305–313 (2019).