Achilles Tendinopathy

What is Achilles Tendinopathy?

The Achilles tendon, sometimes referred to as the triceps surae, is the biggest and most robust tendon in the human body. The tendon acts as the link between three muscles in your lower leg–the gastrocnemius, the soleus, and the plantaris–to the heel bone, also known as the calcaneus. Around the tendon, there’s a layer of cells forming a sheath-like structure, similar to— but not quite a—synovial sheath. We call this a “paratenon”. The paratenon is crucial because it provides a significant amount of blood supply to the tendon.

Research has pinpointed an area of the Achilles tendon that is less well-supplied with blood and therefore more prone to injury. This area is about 2 to 6 cm above the point where the tendon joins the heel bone. The Achilles tendon plays a crucial role in allowing the muscles in your calf to apply force to your heel, which is required for tasks like walking or running.

There are several different factors that can result in Achilles tendon injuries. Certain areas of the tendon are also more frequently injured than others. We are going to discuss specific types of injuries such as insertional and non-insertional tendonitis, paratenonitis, and tendon rupture.

What Causes Achilles Tendinopathy?

Achilles tendinopathy, or the painful and often debilitating condition of the Achilles tendon, can be caused by a variety of factors. These can generally be divided into two categories: intrinsic and extrinsic factors.

Intrinsic factors come from within the body and include things like body build, age, sex, and metabolic issues. It could also be due to issues related to the foot’s shape, differences in limb length, muscle weaknesses or imbalances, or issues with the muscles of the calf (gastrocnemius). Other intrinsic factors could be variations in the structure of the plantaris muscle (a small muscle that runs down the back of your calf), blood supply to the tendon, twisting of the Achilles tendon, slippage of the muscle fibers that make up the tendon, or instability of the ankle.

On the other hand, extrinsic factors are things that come from outside the body. These include things like overworking the tendon, using incorrect or inadequate equipment, being overweight, medication use (corticosteroids, anabolic steroids, and certain antibiotics like fluoroquinolones), unsuitable footwear, not warming up or stretching properly before exercising, being active on hard training surfaces, direct injury, and several others.

Several things can increase the risk of a severe Achilles tendon injury, like a rupture. This includes getting older, inconsistency in the tendon’s structure, slippage of the muscle fibers, and excessive exercise, particularly in athletes. Athletes and others who are physically active are more likely to injure the place where the Achilles tendon attaches to the heel bone.

Risk Factors and Frequency for Achilles Tendinopathy

The Achilles tendon, commonly associated with sporting activities, gets injured quite frequently. It’s estimated that around 24% of athletes get an Achilles tendon injury in their lifetime. If you’re into running, you’ve got an 11% to 85% chance of injury or, to break it down further, 2.5 to 59 injuries for every 1,000 hours you spend running. How likely you are to run into this issue varies quite a bit though. For elite young athletes, it’s 1 to 2%, and for recreational athletes, it jumps to 9%. Interestingly, your likelihood of Achilles tendon injury grows slightly as you age. However, a rupture of the Achilles tendon is relatively rare, with a rate of 2.1 per 100,000 people per year. If you’re male, there’s a higher risk, with men 3.5 times more likely to experience a rupture than women.

• About 24% of athletes get an Achilles tendon injury sometime in their life.
• Runners have an 11% to 85% chance of injury – that’s 2.5 to 59 injuries for any 1,000 hours of running.
• Elite young athletes have a 1 to 2% risk of Achilles tendinopathy, compared to a 9% risk for recreational athletes.
• Sporting activities are related to a lifetime injury risk of 2.35 per 1,000.
• The older you are, the likelier you are to get an Achilles tendon injury.
• Ruptures of the Achilles tendon happen relatively infrequently, at a rate of 2.1 per 100,000 people per year.
• Men are 3.5 times more likely than women to have an Achilles tendon rupture.

Signs and Symptoms of Achilles Tendinopathy

“Achilles tendinopathy” is a term that covers both tendinitis, which is an acute (short-term) inflammation, and tendinosis, which is a chronic (long-term) inflammation. The problem involves pain, swelling, and stiffness in the Achilles tendon, and can happen to anyone, not just athletes. This usually occurs because of an imbalance between the strength of the muscle and the flexibility of the tendon. There are two types of Achilles tendinopathy, determined by where they occur on the tendon: insertional and non-insertional.

Insertional Achilles tendinopathy is where the tendon attaches to the back of the heel bone. People with this type experience pain in the lower third of the tendon, right up to the point where it attaches itself. They may also have stiffness in the morning.

Non-insertional Achilles tendinopathy happens in the middle to upper third of the tendon, about 2-6 cm from where it attaches. If you were to physically feel the area, you might find bumps along the tendon and it could also appear enlarged.

Testing for Achilles Tendinopathy

The diagnosis of Achilles tendinopathy, or damage to the Achilles tendon often resulting from overuse, mostly depends on a physical exam. This examination looks for specific signs like localized pain which means pain in a distinct area of the Achilles tendon, focal or diffuse sensitivity meaning sensitivity over a particular spot or throughout the tendon, swelling, stiffness, and a hardening in the Achilles tendon. The doctor will conduct this examination while you are standing as well as when you’re in a position as if you’re lying down.

There are also special clinical tests performed during the exam. One is called the Arc sign, which checks for swelling or lumps in the tendon as you move your ankle joint. If these swellings or lumps appear to move with the range of motion of the ankle, that could be a confirmation of the presence of Achilles tendinopathy.

Another test is the Royal London Hospital test. In this, the doctor checks for the most tender point on your ankle while it’s in a neutral position and then you’re asked to flex and extend your ankle joint. If the previously tender spot seems to lessen or vanish when the tendon is stressed or put under tension, tendinopathy could be the culprit.

Other diagnostic tools include X-rays and ultrasounds. X-Rays can reveal the presence of certain types of hardening near the place where the tendon attaches to the bone or any abnormal boney growths. They also help to exclude conditions like pathological bone tumors.

An ultrasound meanwhile can be useful for assessing tendon injuries and determining the risk of developing tendinopathy, or a possible rupture. Ultrasounds might show increased thickness of the Achilles tendon or decreases in certain angles related to your muscles, both indicators of potential damage.

An MRI, while providing a comprehensive view of joint structures, isn’t typically the first tool used because of high costs. However, it does enable the viewing of multiple planes and static and dynamic views of your tendon. An MRI might show thickening or degeneration of the Achilles tendon, both signs of chronic intrasubstance tendinopathy.

A CT Scan is typically used to rule out alterations in the bone structure near where the Achilles tendon attaches. However, it does expose the patient to some radiation.

The Victoria Institute of Sports Assessment-Achilles (VISA-A) remains the gold standard for assessing pain and function, and is considered an essential tool in tracking patient recovery post-treatment.

Treatment Options for Achilles Tendinopathy

Achilles tendinopathy is a condition concerning the Achilles tendon, and its management can be grouped into two types: conservative and surgical actions. These therapies depend on whether the condition is new or has been persistent. Usually, for complete tears of the tendon, doctors generally opt for surgical repair.

Conservative treatment comes first for Achilles tendon inflammation. It typically involves the following:

• Lowering activity levels.
• Taking nonsteroidal anti-inflammatory drugs (NSAIDs), which are medications that help decrease pain and inflammation.
• Modifying footwear and employing targeted manual therapy—hands-on treatment—to help speed up the rehabilitation process.

Physical exercises that require the lengthening of the muscle while it is being contracted, known as eccentric stretching exercises, should also be an essential part of the physical therapy. These exercises can reduce pain by about 40%. Additionally, evidence suggests eccentric exercises are superior to the counterpart, the concentric exercises in relieving pain.

If the initial treatments do not relieve symptoms, extracorporeal shockwave therapy (ESWT) may be utilized. This therapy uses sound waves to initiate a healing response, and has been found to relieve pain by about 60% and help to improve the patient’s quality of life. In some cases, combining ESWT with exercises can yield the best results.

Physiotherapy, or physical exercise treatments, can also improve pain and how well the tendon functions when the condition affects the middle part of the Achilles. But currently, there is no strong recommendation towards the use of any specific exercise, thus wearing a brace with specific exercises or orthotics is not currently advised.

Despite using various conservative treatments as the first step in managing Achilles tendinopathy, there is still a lack of comprehensive studies that evaluate the effectiveness of such interventions.

In certain cases, when there is no response to conservative therapy after six months, surgical procedures might be required. The surgical procedures may vary. Some surgeries involve cleaning the tendon area, others are more minimal procedures requiring smaller incisions, while some involve creating numerous tiny burns in the tendon. In some rare cases, a portion of bone may need to be removed, particularly if it’s adding pressure to the tendon area. These surgical procedures can be carried out in different ways, but a review in 2021 found that the use of the lateral takedown approach resulted in fewer complications.

After surgery to remove a portion of the back of the heel bone and treat Achilles tendinopathy, patients can usually return to their previous level of activity within approximately seven months. The success rate is generally high, at over 95%.

For persistently inflamed Achilles tendons, surgery can lead to good functional outcomes and a satisfactory return to sports if the surgical plan is adjusted to match the degree of tendon involvement.

In conclusion, it’s vital to choose an appropriate treatment method depending on the severity of the Achilles tendinopathy. This could range from rest and physiotherapy in less severe cases, to extracorporeal shock wave therapy, and ultimately surgery in more severe cases that don’t respond to other treatments.

What else can Achilles Tendinopathy be?

Pain at the back of the heel and ankle is a frequent issue for people going to their doctors. This kind of pain becomes more common in people who carry extra weight or as individuals get older. If the pain doesn’t decrease after initial treatment, more examinations are needed. Among the usual conditions linked to pain at the back of the ankle are:

• Retrocalcaneal bursitis: can be recognized easily through ultrasound or MRI.
• Kager’s fat pad inflammation: triggers pain when touching both sides of the ankle in front of the Achilles.
• Achilles tendon rupture: confirmed by a positive Thompson test.
• Achilles paratenonitis: ultrasound would show fluid and adhesions nearby the tendon.
• Posterior impingement (Os Trigonum syndrome): triggers ankle pain when forcefully bending your foot up. Normal X-rays can show if Os Trigonum is present.
• Calcaneal stress fracture: confirmed by a positive squeeze test.
• FHL tendinopathy: causes pain during the toe-off phase of walking with additional fluid around the FHL tendon noticed on an MRI.
• Plantar fasciitis: triggers pain when touching the inside of the heel bone.
• Nerve entrapment or neuroma: pain is combined with burning, tingling, or numbness. A positive Tinel sign along the path of the sural nerve can confirm it.
• Heel pad syndrome: causes a deep, pain just like that from a bruise in the middle of the heel.
• Haglund deformity: causes sudden or gradual pain due to a bony prominence at the back of the heel, and often requires surgery.
• Sever’s disease: a condition in kids and teens which affects the part of the heel bone that is still growing.
• Insertional calcific tendinosis: worsens over time in patients with high body mass index and needs a surgical procedure.
• Lumbar (S1) radiculopathy: triggers pain with a decrease in feeling over the back outer ankle.
• Erdheim-Chester disease (ECD): a rare condition caused by non-Langerhans cells reported in a man who presented with masses in both Achilles tendons.

As always, we should also consider the possibility that the pain could have more serious underlying causes.

What to expect with Achilles Tendinopathy

If you’ve got Achilles tendinopathy, it’s important to start treatment early for the best outcome. Surgery for this condition (also known as Achilles tendinosis at the point where it attaches to the heel bone) is successful in over 80% of cases. A study showed that the chances of non-surgical treatment not working increased if other risk factors were present.

These risk factors include higher levels of pain, limited ankle movement, past corticosteroid injections (a type of medication containing synthetic forms of cortisol, a hormone naturally produced by your body), and the development of abnormal bony growths in your Achilles tendon. If you have these risk factors, it helps doctors decide if surgery is the right option for your situation.

Another study found that strengthening the Achilles tendon using a bone-tendon autograft (a procedure that uses tissue from your own body to repair and strengthen the tendon) is effective, isn’t likely to cause complications, and produces reliable results.

Possible Complications When Diagnosed with Achilles Tendinopathy

In treating Achilles tendinopathy through surgery, complications can occur ranging from 3% to 41% of cases. A study by Lohrer and his team found that both traditional and minimally invasive surgery had similar success rates of around 83.4%, and patients were similarly satisfied with both types of surgery. However, less complications were found in the less invasive surgeries.

Baltes and his team sorted the complications into major and minor categories:

Major Complications:

• Tendon tearing or rupture
• Any kind of reoperation
• Deep vein thrombosis (DVT)
• Reflex dystrophy (a disorder of the nervous system)
• Continuous nerve pain
• Deep seated infections
• Strong reactions to deep sutures
• Significant wound issues

Minor Complications:

• Discomfort
• Skin-deep infections
• Minor wound issues
• Sensitivity around the scar
• Thickening of scar tissue
• Mild temporary numbness
• Extended hospital stay

The complication rates can also be different depending on whether the surgery is for insertional or non-insertional Achilles tendinopathy. Complications can occur in as many as 41% of cases post-surgery for insertional Achilles tendinopathy, whereas they can reach up to 85% in cases following non-insertional Achilles tendinopathy surgeries.

Recovery from Achilles Tendinopathy

After an Achilles tendon surgery, patients need to keep the affected area still, which is called immobilization. This can be achieved with the help of a cast, walking boot, or even a splint inserted behind the calf. The period of keeping the foot still can last anywhere from 3 to 8 weeks. Though, recently, a growing number of studies suggest that patients should start putting weight on the foot sooner, as part of their recovery process.

In 2021, a group of researchers led by Arunakul did a study where they compared the traditional healing process after Achilles tendon surgery and an enhanced recovery plan that encourages the patient to start bearing weight sooner. They found that this new, speedier program can improve the patient’s functionality in the short term. The details of both the conventional and accelerated weight-bearing protocols are as follows:

The traditional recovery program looks like the following:

• Weeks 0-2: Patients are not supposed to put any weight on the treated foot while it is immobilized in a cast or splint.
• Weeks 2-4: Patients start slightly putting weight on the foot (25%) using underarm crutches in a special boot equipped with a heel lift of 2.4 cm.
• Weeks 4-6: Patients move to putting half their weight on the foot using axillary crutches and decrease the heel lift to 1.6 cm.
• Weeks 6-8: Patients then put most of their weight (75%) on the treated foot in the boot with a decreased (0.8 cm) heel lift.
• Weeks 8-10: Patients walk with full weight bearing, still using crutches, in the boot without a heel lift.
• After the 10th Week: Patients can transition back into their regular shoes as they feel comfortable.

The accelerated recovery program, on the other hand, is a bit quicker:

• Weeks 0-2: Just as in the traditional program, no weight is put on the foot and it is kept in a cast or splint.
• Weeks 2-3: Patients move to fully putting weight on the foot as tolerated in the boot with a 2.4 cm heel lift.
• Weeks 3-4: The situation remains largely the same, but the heel lift is reduced to 1.6 cm.
• Weeks 4-5: The heel lift becomes 0.8 cm, but the weight bearing remains the same.
• Weeks 5-6: Patients walk bearing the entire weight in the boot without a heel lift.
• After Week 6: Patients transition into their regular shoes when they feel ready.

Preventing Achilles Tendinopathy

Educating patients and taking a more careful approach can help prevent long-term tendon damage. Several methods backed by scientific studies include:

* Changing Your Sport: Switching to activities that are less strenuous, such as swimming, weightlifting, rowing, or cycling, gives the Achilles tendon (the tendon connecting your calf muscles to your heel) time to rest and recover.
* Controlled Exercise Therapy: By incorporating exercises that gradually lengthen your muscle-tendon unit in a controlled way, pain can be reduced and the progression to long-term tendon damage can be prevented.

Medicine like ibuprofen and naproxen (known as non-steroidal anti-inflammatory drugs, or NSAIDs) can be used to help reduce swelling and manage pain. These medicines are considered conservative treatments, meaning they’re non-invasive and have less risk than more aggressive treatments.

Choosing the Right Footwear: Running shoes that have good cushioning and support the heel can reduce stress on the Achilles tendon.

Warming up and Stretching: Stretching your calf muscles before engaging in sports or exercises is always beneficial.

Making Gradual Progress: Try to only increase your distance and speed by 10% every week. Avoid sudden increases in intensity, avoid running on uneven surfaces, and make sure you cool down after exercise. These precautions can prevent putting too much stress on the Achilles tendon.

Using Physical Therapy: Extracorporeal Shock Wave Therapy (ESWT) is a non-invasive treatment that uses shock waves to stimulate healing in the Achilles tendon. It can be useful if other treatments haven’t worked well.

Surgery is usually kept as a last option for when all other treatments haven’t improved symptoms, or if the tendon has significantly torn.