Achilles Heel: Perhaps it was tendinopathy?

Of course it wasn’t tendinopathy but it sounded good! Greek mythology of course depicts that Achilles as a child was dipped by his mother in the river styx to immortalise him but failed to do his heel. Achilles was a great war hero, his ultimate demise was the result of a poisoned arrow to that very heel. Now it’s no arrow to the heel but tendinopathy is a debilitating problem leaving the sufferer in pain and unable to compete in their sport. I take you through the latest evidence on Achilles Tendinopathy with some real groundbreaking evidence…… part of thenakedphysio’s commitment to bringing you cutting edge info…..

Introduction

Achilles Tendinopathy as it is now known refers to a pathology of the Achilles tendon. Only within the last 10 years has tendinitis been reclassified as tendinopathy. Tendinitis (itis referring to inflammation) was discouraged when studies of tendons found no inflammation to be present.

Achilles tendinopathy is a common complaint for many elite athletes, but also in individuals that exercise regularly or those that have infrequent bouts of exercise. Sports such as football and running have a high prevalence of achilles tendinopathy due to the nature of the loading associated with such sports (reference, reference). There are many factors that can be a cause of achilles tendinopathy including, changes in terrain, footwear, duration of activity, co-morbidities (diabetes), physical condition of the individual, biomechanics, age, genetics, sex.

What most of the above factors relate too is load. Tendons don’t like rapid change! They are the equivalent of the beach happy person watching the crazy friend or partner doing the adrenalin sport. Happy to do just enough, but with some encouragement and a graded approach the beach happy person may slowly get involved and may enjoy the activity. If we push too much the beach happy person may object! Tendons are the same, If we change the load on a tendon very rapidly tendons will object.  If we continue to do this frequently then most certainly a change will occur in the tendon structure, resulting in the structure of the tendon becoming less efficient at dealing with load. The more you load the tendon incorrectly the further you compound the problem.

Anatomy and physiology

The Achilles tendon is the large band like structure at the back of the leg.  It inserts into the calcaneus (heel bone) originating from the gastrocnemius and soleus muscles.  It’s main action is to point the foot, which means it is an extremely important muscle for propulsion – walking, running, jumping and landing.  It is surrounded by a peritendon, which is a very thin membrane that nourishes the tendon.  The peritendon can become inflamed resulting in a peritendonitis. Some tendons are surrounded by synovial sheaths such as in the wrist and ankle. A synovial sheath is a membrane that surrounds the tendon bathing it in synovial fluid reducing friction on the tendon when it crosses a joint. The achilles tendon does not have a synovial sheath, but is surrounded by bursa which play the same role of reducing friction to the tendon.

Tendons are comprised of collagen type I and water.  Tenocytes (cells in the tendon) monitor the forces within the tendon. When a rapid change in load occurs tenocyte numbers increase resulting in an increase in water, which causes the appearance of swelling.

Tendons are incredibly complex structures, they are designed to tolerate load.  Davis’s law and Wolff’s law are synonymous with understanding the basis of load on soft tissue and bone respectively. An increase in load according to each law explains that the tissue will adapt.  However as previously mentioned too much load and if repeated frequently can lead to a tendinopathy or rupture or regarding bone, a stress fracture.

Common sites of Pain

The picture above shows classification of where pain may arise around the Achilles or calcaneus.  This is not exclusive as there are lot’s of other structures in the area that may give rise to symptoms similar to those shown above, including nerve entrapment, plantar fascitis, sever’s disease, calcaneal fracture, fatpad (reference).  Tendon pain is confirmed by localised pain.  Pain should not be diffuse or be referred.  I stress that if you experience any of the above please get checked by a professional. Lets take a closer look at each:

Mid-Tendon – This is an enlargement of the middle of the tendon an a common site for tendinopathy.  You may see a bump form in this area

Insertional – Irritation occurs at the insertion or enthesis, this is associated with coexisting pathologies at the insertion such as retro-calcaneal bursitis (reference, reference).

Haglund’s Morphology – Commonly known as a Haglunds deformity, it is regarded as an abnormal bone growth on the heel. Evidence has suggested that Haglunds deformity should be re-classified as a morphology as it acts as a fulcrum to decrease the stress on the tendon (reference, reference).  A Haglund’s deformity is not associated with insertional Achilles tendinopathy (reference, reference).

Plantaris – Associated with medial Achilles pain.  The Plantaris can rub against the Achilles tendon causing compression resulting in symptoms.

Causes of Achilles Tendinopathy

So I have spoken about the physiology of tendons and the tendinopathy continuum in another post (patella tendinopathy).  I talked about the tendon make up and the various stages of tendinopathy from reactive to degenerative. I intend to talk a bit about what causes tendinopathy and then how you can manage the stages particularly a reactive stage and a degenerative stage.  As with patella tendinopathy an Achilles tendinopathy will occur when there is a load change.  I mentioned earlier, changes in footwear, terrain, training levels etc can have an effect on a perfectly healthy tendon.  Sorosky et al, 2004 highlight 5 components that affect anatomy and function this includes:

(1) tissue injury—the anatomic distribution of pathology; (2) clinical symptoms— the complaints of acute pain, swelling, and dysfunction; (3) functional biomechanical deficits—the combination of muscle inflexibilities, weakness, and imbalances causing inefficient mechanics; (4) suboptimal functional adaptations—the inadequate adjustments made in an attempt to maintain performance and minimize symptoms; and (5) tissue overload—the anatomy subject to excess tensile or eccentric stress

This highlights the multifactorial complexity of identifying the cause of Achilles tendinopathy and possible contributing factors to determine what best management would be appropriate. The above factors should be taken into account as with others in a clinical examination when seeing a physiotherapist or other health professional.  Identifying the stage of the tendinopathy will help with its management.  A physiotherapist can then provide an appropriate management plan around subjective and objective findings.

Inflammation

This is a controversial subject as it was proposed that inflammation wasn’t apparent in tendons after histological studies examined the tendon and found no inflammatory markers.  Inflammation is not clearly defined regarding its role in tendinopathies despite some evidence suggesting its existence (reference).  Inflammation is commonly associated with pain, although tendon pain is not clearly defined as it is not one clear mechanism that explains its clinical features (reference).

Rupture

This leads me onto Achilles tendon rupture and the ring doughnut theory.  One of the issue with Achilles tendon rupture is that because we cannot clearly define tendon pain ruptures in tendons can spontaneously occur without any preceding symptoms (reference).  What has been shown is that Achilles tendons that do rupture have been shown to have clear degenerative changes.  So with this in mind we should consider management very carefully.

Management of Achilles Tendinopathy

So managing an achilles tendinopathy, well you could do what Achilles mother did but It didn’t work for him so lets stick to conventional methods. 🙂 ok I hope you’re sitting comfortably because I may go on for a while.  It’s important that we revisit the stages of tendinopathy as there are different treatments for each. It’s not a ‘one treatment fits all’ approach. Lets revisit a reactive tendinopathy.

Reactive Tendinopathy

A reactive tendinopathy usually occurs in response to a rapid increase in load, this includes compression.  You may get pain with this and see swelling in the tendon.  This applies to those of us that regularly exercise and those that don’t.  Changing the terrain, footwear, training intensity or performing an acute bout of loading – sprinting, running for a bus etc (to those individuals that don’t exercise), is enough for a tendon to object.  Management of a reactive tendon is about decreasing load.  It involves relative rest (not complete rest) to allow a reduction of symptoms over a couple of days.  Avoiding high load that would include tensile and compressive forces. Anti-inflammtories although associated with inflammation have been shown to slow down the cellular process that causes a reactive tendinopathy.  Be sure to consult your GP about this.

Tendons are pretty strong structures being able to withstand up to 8 times your own body weight.  Reduction of tensile stresses such as high impact aerobic exercises, running, jumping or bounding is recommended.  Compressive forces can occur at the insertion of an Achilles tendon if a Haglund’s morphology is present. The retrocalcaneal bursa becomes inflamed and compresses the tendon. (reference, reference).  Positions where your foot and ankle are in dorsi-flexion will increase the compressive forces, so how tempting it may be, stretching your calf or Achilles is definitely a no no! Fortunately a reactive tendon is reversible and will settle, usually  within 3-4 days of relative rest.

Isometric strengthening, which is a static contraction of the muscle has been shown to reduce pain and maintain muscle strength in reactive tendons. Remember we want to avoid compressive forces so performing eccentric strengthening on a reactive tendon or an insertional tendinopathy is not recommended.

Degenerative Tendinopathy

Degenerative tendinopathy is more common in adults between ages 30-60.  It describes a disorganised state of collagen fibres, which is non-reversible. Tendons in jumping athletes over the age of 30 years can have up to 40% degenerative change in a tendon. It is not all bad news as the evidence suggests that treating the ring not the hole is the best approach. What I mean by this is an area of degenerative tendinopathy cannot be changed however healthy tendinous tissue surrounding the area of degeneration can be trained to increase the load tolerance. Important!! This must be done in a graduated way.  

red = healthy tendon Blue = degenerative tendon

Risk factors

It is also particularly important to consider risk factors when managing tendinopathy.  This includes factors such as diabetes, or obesity, previous injuries or other invasive treatment such as injection as these can lead to higher risk of developing tendinopathy or even rupture.  Interestingly high cholesterol levels and increases in visceral fat, which excretes pro-inflammatory markers were linked to Achilles tendinopathy.

The use of fluoroquinolones a form of antibiotic has also been shown to have a direct correlation to tendinopathy and ruptures (reference, reference).  So if you are or have been on this form of antibiotic it may be wise to regulate your training and maintain your cardio-vascular fitness through other means such as cycling and swimming. Discuss this with your G.P.

Tendinopathy management

It’s important that you are able to recognise the signs when it comes to managing tendinopathy. Remember it is not one recipe or one approach fits all. You need to be able to recognize what flares up your symptoms and approach your rehabilitation in a graduated way.  Eccentric strengthening has been shown to improve degenerative tendinopathy strength by increasing the strength of the surrounding healthy tendon tissue. Hopefully this post and my previous post on patella tendinopathy (here) will give you some insight into best management.

However the information up here does not replace a professional.  A thorough assessment of your sports and injury circumstances are really important to ascertain the nature of your injury and to help direct your rehabilitation. Periodisation is an important part of training in elite athletes. It is the timing, sequence and interaction of the training stimuli to allow optimum adaptive response in pursuit of specific goals. In other words it is important to know why, how and when to increase the load on a recovering tendon in order to maximize the outcome.  In addition you need to keep training in order for your tendons to maintain their optimum load tolerance. The charts below provide an example of timing training on the adaptive response (reference). This will be variable throughout your rehabilitation and training and will depend on your fitness, recovery, diet etc.

So hopefully that has given you an insight into the complexity of Achilles tendinopathy. I have touched on periodisation in this post as it is pertinent to all rehabilitation and training regimes.  It is particularly important if you are a keen athlete that competes in Ironman’s or triathlons for example.  A common mistake by athletes is that we become obsessive about our training and we can often train through our symptoms because we have a goal to work towards i.e. a competition or breaking a personal best.  Periodisation will be discussed at a later date on thenakedphysio.  Remember if in doubt get it checked out.

Thanks again for reading, please don’t hesitate to post any comments you may have.

TNP