Achilles tendinopathy…… or is it?

By Becky Webber, Physiotherapist at Kinetic Sports

We all know Achillies tendinopathy (AT) is an annoyingly common running injury, thought to plague one in twenty. However, as physios it is our job to rule out other possible causes that have similar presentations to ensure appropriate rehab. We thought it would be helpful to briefly discuss some of the other culprits

Let’s start with sural nerve irritation, the sural nerve runs down the back of the calf alongside the Achilles and down the outside of the foot. It is purely a sensory nerve so wont impact muscle function. Although less common than AT it can get trapped along its path which can cause pain in the outside portion of the Achilles.

Running up a flight of steps

Next on the list of differentials is Flexor Hallucis Longus (FHL) tenosynovitis which is inflammation of the sheath that surrounds the tendon. This tendon runs deep to the Achilles and can therefore mimic AT symptoms. It is useful to distinguish between the two as there are different rehab exercises that can be prescribed that may speed up your recovery.

Another to be aware of is the Plantaris muscle which originates behind the knee, with its tendon inserting around the heel. Like the Achillies, the Plantaris tendon can become inflamed, although this is less common. Plantaris tendinopathy can be difficult to differentiate from AT due to how close it sits to the Achilles; in some cases, it inserts into the Achilles. However, it can be a primary source of pain and should therefore be considered in treatment, especially if you feel you aren’t getting anywhere with your AT rehab. There can be small changes made in rehab to reduce inflammation of Plantaris for example avoiding exercises that involve a heel drop.

One that is often overlooked is bursitis. We have several bursa (fluid filled sacs that stop the rubbing of bones and soft tissue around joints) in the heel area. The most prone to irritation is the Retrocalcaneal which sits between the heel bone and the Achilles and can often be mistaken for AT. Again, treatment of this differs from how you would manage AT and is well worth considering during the diagnosis of your heel pain.

Another injury that can mimic AT symptoms is posterior ankle impingement. This is where structures around the back of the ankle joint can get entrapped this can be due to many reasons like inflammation/scarring, bony growths and increased mobility. Pain usually occurs when the foot is pointed (pushing off your toes during the running gait cycle).

As you can see there is a lot to consider in the treatment and diagnosis of AT, if this is something you are struggling with then please reach out.

Happy running!