Achilles Tendon injury is the third most common sports injury in the area of the foot, after ankle sprains and plantar fasciitis. The prevalence of the injury is estimated to be 11% of all running injuries in athletes. One-fourth of the Achilles tendinopathies is located at lower portion of the back of the heel Middle-aged male athletes are considered to have a greater risk of developing Achilles Tendon injury, although high rates (31% of all Achilles injuries) have also been reported in people who don’t participate in sports. Often professionals are puzzled as to how to resolve this tendinopathy

Anatomy and Histology

The Achilles tendon is a tendon formed from the calf muscle, which is formed from the gastrocnemius and the soleus muscles. The gastrocnemius is a 2 joint muscle, as it starts above the knee joint, and ends at the back of the heel in the form of ACHILLES tendon . Soleus, on the other hand, starts below the knee and connects to  the achilles tendon .

The Achilles tendon inserts not only into the calcaneus but also connects to the plantar fascia and the two structures act as a continuum. The tendon’s fibers rotate in its insertion into the calcaneal bone at approximately 90 degrees, with the medial fibers coming posteriorly and the lateral fibers coming inferiorly .

The insertion of the tendon is protected by two fluid filled sacs called BURSA , the retrocalcaneal, which is between the Achilles and the skin, and the retro Achilles, which is between the Achilles and the calcaneus. The area of the Achilles insertion, the calcaneus, and the two bursas are known as the enthesis organ.

The Achilles tendon does not have a true sheath, but it is covered instead by a loose, fatty sheath called paratendon. The paratendon provides vascular supply to the achlles tendon and helps it to glide with minimal friction within the sheath. Deeper to the peritendon is the endotendon, which encloses the collagen fibers of the tendon, its small blood and lymph vessels, and its nerves.

Blood supply to the tendon is also provided by the musculotendinous junction and through its attachment to the bone.

“The area 2-6cm above the tendons insertion has been proposed to have poor vascularity, which explains why it is prone to injury

As far as the histology is concerned, the tendon consists of cells and extracellular matrix . Approximately 95% of the tendon’s cells are tenocytes and tenoblasts, with the rest 5% being chondrocytes, vascular cells, synovial cells and smooth muscle cells.

Biomechanics of the tendon

The Achilles tendon has a dual action, to transmit forces from the muscles to the bone and to absorb ground reaction forces that could cause injuries to the muscles.

The fibers of the tendon have a wavy arrangement, which is lost when it is stretched more than 2%. Further increase in the  elongation to the tendon, till the critical point of the 4% of its original length, causes microtrauma to begin . If the elongation reaches 8%, then macroscopic rupture happens .

The tendon is able to withstand large amount of forces, as it is estimated that during sprinting the load can reach 12.5 times the body weight  and during squat jumping the amount of 2233 N . The rotation of its fibers, described above, is believed to help the tendon store and release energy during movement.

Aging, as well as disuse, has been shown to reduce the tendon’s stiffness and its ability to resist loads .

 

“Resistance training can help in restoring tendon’s normal function and in fact a lot quicker than it was previously believed . Researches showed 65% increase in tendons stiffness with 14 weeks of resistance training, without any change in the macroscopic dimensions of the tendon . This outcome is probably a result of improved metabolic activity of the tendon and points out the important role of exercise in reducing injury risks .”

From a biomechanical point of view,

• the abnormalities of the foot posture like pronated foot  and high arched feet are thought to overload the tendon.
• Moreover, decreased range of dorsiflexion has been proposed to increase the ground reaction forces and therefore injure the tendon .
• Calf weakness and poor coordination of the whole lower limb has also been observed in patients with tendinopathy.

Another research explains an important question of the relationship between pain and function in the case of Achilles tendinopathy. it explains how continuous loading on a tendon can push it to a stage of tendon dysrepair (leading to a tear in the tendon). Interestingly this same research also explains that if the tendon is found to be under distress and put through optimal loading can also go back to normalcy

Pathology

Achilles Tendon injury can be an acute and overuse injury.

An acute Achilles Tendon injury follows the same healing principles as every other area of soft tissues, starting with inflammation and eventually healing into a scar tissue.

Chronic Achilles Tendon  injuries, though, do not seem to follow the same procedure . The microtrauma caused to the tendon does not produce inflammation, thus there is poor healing of the tissues. This condition is described as “failed healing response”.

There are four basic elements seen in the majority of the patients with degenerative Achilles:

1) Altered cell function. The metabolism of the cells increases in order to produce more collagen and ground substance

2) The amount of proteoglycans in the ground substance increases

3) Microrupture of the collagen type I fibers and production of the thinner type III- which makes the tendon fragile

4) Appearance of new vessels and nerves into the tendon as a result the tendon is more sensitive than normal

The degenerative Achilles tendon does not have macroscopically a normal white shape and it rather looks grey and unstructured . Instead of parallel orientation, there is a random orientation of the collagen (especially type III), of the ground substance and of the vessels, which makes the tendon less capable to withstand loads .

Although, there is not true tissue inflammation in Achilles tendinopathy, evidence of neurogenic inflammation exists .  Substance P, CRGP and glutamate have been found in symptomatic chronic tendinopathies .

Research states that chronic tendinopathies could be in fact caused by nerve tissue dysfunction, rather than being the result of repetitive overload of the tendon. considers it possible that local nerve damage in the Achilles area could be produced by long distance running due to the repetitive load, in a similar way that vibration causes trauma to the tissues. may be thats the reason, the tendon takes upto 12 months to reverse back to normalcy post rehab??

Moreover, a potential nerve pinch  in the lower back region, the buttock area or between the two heads of calf could have a similar impact on the tendon.

we at physiocure are extra careful when examining patients with Achilles tendinopathy for identifying possible neurological deficits. In case that a patient indeed has neurological/neurodynamic discrepancies, we utilize techniques such as mobilization of the nervous system for the management of tendinopathy.

Aetiology

Due to the complexity of the condition, for a better understanding of these risk factors, they have been classified into two categories, the extrinsic and the intrinsic ones.

One of the main extrinsic factors, traditionally considered to be highly correlated with tendinopathy, is the amount of training. The repetitive loading is believed to cause microtrauma to the tissues and gradually lead to symptom production. Other extrinsic factors include the potential poor technique used by the athlete, as well as the type of footwear and the type of surface that can change the ground reaction forces and place increased load on the tendon.

As intrinsic factors can be mentioned a wide variety of reasons comprising the foot biomechanics, the whole kinetic chain function, and the effect of genes, age, gender, and obesity in the development of Achilles tendinopathy. people suffering from Achilles rupture in one limb, have increased possibilities of rupturing their tendon on the other leg as well. Males are considered to be more prone to the condition than females and the injury becomes more frequent as age progresses.

Clinical Findings:-

• A careful subjective examination of the patient will reveal that the area of the symptoms in the midportion tendinopathy is along the main body of the tendon , while in the insertional the pain is experienced at the tendon’s insertion .
• Achilles tendinopathy pain does not usually refer to other areas .
• The pain can vary from minor to severe and may be accompanied by swelling, thickening and crepitus . If crepitation coexists, the paratendon is involved in the pathology too , although it is not common in chronic cases .
• The pain at the first stage of the disease appears at the beginning of the training and immediately after it, with no symptoms in-between.
• If it progresses it may not allow the patient to participate in sports and pain may be even present during his daily living activities .
• Running and hoping usually aggravate symptoms , while rest, slow walking and heat relieve them .
• Morning stiffness is one of the main complains of the patients .
• The history reveals a sudden onset of symptoms after an increase in the intensity, the frequency or the duration of training .

The objective examination we check for the following:-

observation of the patient for

1. muscle bulk wasting,
2. swelling of the tendon as well as for
3. malalignments of the foot .
4. Single-leg heel raises (are useful as pain provocation test, but also to assess the muscle-tendon unit strength and endurance .)
5. hopping .(In athletes that might need a more challenging test for pain reproduction)

The palpation will reveal any possible

1. thickening,
2. increased heat,
3. areas of tenderness or
4. crepitus

Finally, we believe. it is very important to assess the whole kinetic chain of the lower limb and pelvis for possible impairments that might contribute to the problem .

The calf squeeze test is a quick test done in clients who might be suspected for tendon rupture

Paratendonitis

The “painful arc sign”, is uded for differential diagnosis of paratendonitis in clients to understand the type of achilles tendinopathy. If the area of maximum tenderness is palpated, then the foot is moved from plantar to dorsiflexion and the area of tenderness remains in the same position, in that case the paratendon is the source of symptoms .

The retrocalcaneal bursitis

Usually presents as a prominent warm area of the back and the outer part of the heel. In the retro-Achilles bursitis on the other hand, pain presents as very superficial and the area of the back of the heel is warm

while in the insertional tendinopathy the pain is around the central part of the back of the heel .

Lastly, our physiocure clinicians  always remember that enthesopathy is a common symptom of rheumatoid arthritis and spondyloarthropathy so the diagnosis is made accordingly.

Management

The Management for Achilles tendinopathy changes with each diagnosis slightly.

There separate rehab programs for midportion, insertional tendinopathy, a different approach for retrocalcaneal bursititis and a proper post operative rehab program for a tendon tear

The main goals of management are

1. Alleviate pain
2. Work on improving range of motion
3. The entire kinetic chain functioning is addresed
4. Most important, improve load bearing capacity on the tendon
5. Restore balance sensation
6. Return to sport gradually.

 

The use of exercise as a treatment for Achilles tendinopathy involves 2 important clinical questions: what is the most effective type of exercise, and what is the most appropriate dosage?

The Alfredson protocol uses eccentric exercises and A different progressive Achilles tendon–
loading strengthening program promotes exercise once daily and uses concentric/eccentric exercises. each physiotherapist chooses one of the two programs based on their knowledge and experience. however some facts do remain that the alfredson protocol do not appear to be so effective in the insertional tendinopathy.

From a physical therapy point of view, other interventions with obviously lower levels of evidence have been proposed, like soft tissue mobilization, rest, ice, orthoses and heel lift . Heel lifts are useful in insertional tendinopathy because they prevent ankle joint dorsiflexion and as a result the impingement of the tendon to the calcaneus is avoided .

Moreover, orthoses can improve the alignment of the foot and thus normalize the loads applied on the tendon .

Additionally, the application of ice reduces the patient’s pain and declines the metabolism of the tissues . The soft tissue mobilization techniques, on the other hand, are supposed to gradually increase the tendons tolerance to loading , but it does not work with all cases.

Non physiotherapy interventions have also shown very satisfactory results. The sclerosing injections eliminate the new vessels growing into the tendon and possibly the nerve endings that accompany them, dramatically decreasing in this way the pain that patients experience .

Combinations of eccentric exercise with electrotherapy seem to be more effective than eccentric exercise alone which we follow for most of our clients followed by return to sport program

Lastly, a very important recommendation for the clients who are reading this is ,not to forget to address possible impairments of the whole kinetic chain, including the lower limb and the lumbopelvic region, rather than focusing only on a particular treatment protocol .

Return to sports

A short recovery time and an early return to sports without a gradual loading of activities is a recipe for reinjury or repeated tendoachilles strains. we do not recommend our players to stop playing while they are undergoing rehab for 8 to 12 weeks , but instead we recommend them to perform activities that will promote healing and restrict activities that will worsen the tendon. after a certain point in rehab the players do not have nay symptoms and hence they may be tempted to return to playing early.

Under a guided rehab program symptoms like pain, swelling, stiffness are monitired and give an idea on wether to further increase the activity level or not.

Here is a small table explaining how a runner will feel when he starts running and what should it feel like. for instance, if walking for 70 minutes causes pain more that 2 (as per the pain scale) you have not recovovered yet to pursure walking . you need to take it easy.

 

AS PER THIS RESEARCH BASED PROOF, WE RECOMMEND AN ATHLETE TO START WITH RUNNING OR JUMPING ACTIVITY ONLY IF ACTIVITIES OF DAILY LIVING ARE PAIN FREE

 

	Classification of activities
	Light	moderate	Heavy
Pain level during activity , NPRS (0-10)	1-2	2-3	4-5
Pain level after activity (next day)	1-2	3-4	5-6
Athletes’s RPE in regards to the Achilles tendon	0-1	2-4	5-10
Recovery days needed in between activities	0	2	3
Examples of activities for a runner	Walking for 70 mins	Jogging on flat surface for 30 minutes	Running at 85% of preinjury speed for 20 minutes
Abbreviations:- NPRS- numeric pain rating scale, RPE- rate of perceived exertion

The return to sport program is introduced, within few weeks of the start of the rehab program. the athlete is educated even if  they do not wish to follow a return to sports phase. for atheletes who do sign up a training diary is made and they are asked to note down symptoms as per the daily schedule.

we can help you recover with a guided rehab program, to sign up for a rehab program talk to us via the chatbot!!

References:-

 

1. Alfredson, H & Cook, J 2007a, ‘A treatment algorithm for managing Achilles tendinopathy: new treatment options’, British Journal of Sports Medicine, vol. 41, no. 4, pp. 211-216.

2. https://bjsm.bmj.com/content/50/19/1187

3. Alfredson, H & Ohberg, L 2005, ‘Sclerosing injections to areas of neo-vascularisation reduce pain in chronic Achilles tendinopathy: a double-blind randomised controlled trial’, Knee Surgery and Sports Traumatology Arthroscopy, vol. 13, no. 4, pp. 338-344.

4. Cook, J, Khan, KM & Purdam, C 2002, ‘Achilles tendinopathy’, Manual Therapy, vol. 7, no. 3, pp. 121-130.

5.https://www.researchgate.net/publication/282047223