James Gasper
The Achilles tendon is one of the most commonly injured tendons in the body and unsurprisingly it is therefore an injury we see a lot of. This blog will be a quick run down on the fundamentals of what an Achilles tendinopathy is and how we treat them.
What is a tendinopathy?
Unlike an acute muscle tear or a broken bone a tendinopathy is a more complex multifaceted injury. It is generally an overuse injury where the tendon (tendons are what attach our muscles to our bones) has been repeatedly pushed beyond its capacity. These injuries are characterized by pain, a decline in function and reduced exercise tolerance. Structurally we see a disruption of the collagen fibres and a deregulation of the extracellular matrix – the building blocks of the tendon and why we see the reduced function. There is also increased inflammatory mediators and sensory nerve innervation – which explains the pain.
Achilles Tendon
We have tendons all over our body and these injuries are seen in the shoulder with rotator cuff tendons, the knee with the patella tendon and the hip with the gluteal tendons (as well as the elbow, wrist and groin). The Achilles tendon (named after the famous Greek Warrior God) is the largest and strongest tendon in the human body. It is approximately 15cm in length and rotates clockwise up to 90 degrees, running from the soleus and gastrocnemius muscles and inserting into the back of the heel. The tendon is surrounded by a paratenon allowing it to glide back and forth. It is made up of Type I collagen giving it the ability store and release energy so that it can stretch and recoil like a spring in response to the stretch/shortening cycle of the calf complex – an important action for locomotion.
This unique structure allows the Achilles to withstand fast and dynamic loads, which can be up to 7 x a persons body weight during running and jumping activities.
It also makes rehabilitation of this tendon very challenging.
Loading Programs
As with all tendinopathies the key to successful management is load control. This goes back to the original cause of the injury that, in the majority of cases, is due to the tendon being subjected to excessive loads for too long.
In severe cases, for the Achilles tendon, this can result in needing a Cam boot to completely unload the tendon. In more moderate cases, a simple heel wedge in a supportive pair of shoes is adequate.
Loading exercises are then prescribed at different intensities depending on the stage of the tendinopathy. These exercises will range from static holds (isometrics) in the initial stages, slow heavy resisted movements in the mid-stages and fast resisted movements (plyometrics) in the later stages.
For the Achilles tendon, in severe cases, an initial exercise may be a simple seated calf raise with limited loading through the tendon. This would then be gradually progressed over a number of months. End stage can involve hopping drills and single leg loads of up to 1.5 x body weight.
Throughout this program the alignment of the foot and ankle need to be monitored to ensure efficient load transfer through joints and tendons. In some cases the exercises have to be modified to the individual. An example of this would be when the patient has an arthritic great toe – this will alter their ability to perform a calf raise.
Return to Running
As we work through this loading program our rehab becomes more functional and we try and make it specific to the individuals goals.
A good example of this is getting athletes back running – with Achilles tendinopathies being a frequent injury associated with both competitive and recreational runners. A safe return to running program is an important part of their rehab process. The loads that go through the tendon when running are at a high tempo and can be between 5-8 x body weight. It is therefore wise to introduce running gradually with slow exposure to these loads ensuring that the tendon has time to adapt.
Take home message
· The Achilles tendon is a complex structure capable of tolerating impressive loads that enables us to walk, run and jump.
· An Achilles tendinopathy is when this tendon has been loaded beyond is capacity causing a number of pathological changes.
· To manage these injuries a loading program needs to be introduced – but getting the right intensity of loads with the right timeframes can be frustrating and is likely to be different for each individual.
· This program needs to be progressed through stages and in line with the individuals goals – not all rehab programs will be at the same intensity.
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