Achilles Tendonitis

The Achilles tendon is the single strongest tendon in the human body. The primary function of the Achilles tendon is to transmit the power of the calf to the foot enabling walking and running. If it has to do with upright, bipedal motion, the Achilles tendon is a part of that activity. Occasionally, the Achilles tendon can fatigue, begin to show signs of inflammatory change and develop Achilles tendonitis. This article discusses the onset, symptoms and treatment of Achilles tendonitis.

Acute Achilles tendonitis

Acute Achilles tendonitis (also known as Albert's Disease) typically has a abrupt onset with moderate to severe pain found at either the insertion of the tendon in the back of the heel (insertional tendonitis) or in a location 2-3 cm proximal to the tendons' insertion. Many individuals who suffer from acute Achilles tendonitis can describe an injury or single event that initiated the pain. Symptoms of acute Achilles tendonitis occur at the beginning of an activity and are typically described as sharp pain. As the activity continues and the Achilles tendon 'warms up', the Achilles tendon pain begins to feel a bit better. With excessive use, the Achilles tendon again becomes painful at the end of activity. For example, runners with Achilles tendonitis experience pain as they begin their run. The pain subsides during their run only to recur near the end of their normal running distance.

Chronic Achilles tendonitis (tendonosis)

Chronic Achilles tendonitis is also called Achilles tendonosis. Chronic Achilles tendonitis can also cause hypertrophy (enlargement) of the posterior heel and distal Achilles tendon. When viewed on x-ray, this finding is called an increased Phillip-Fowler angle.

In cases of chronic Achilles tendonitis it's important to differentiate between pain strictly due to the pull of the Achilles tendon and pain due to the enlargement of the posterior heel rubbing against the shoe called a pump bump or Haglund's deformity. The difference between Achilles tendonitis and a pump bump can be understood by evaluating the pain while barefoot (suggestive of Achilles tendonitis) compared to pain while wearing shoes with an enclosed heel (pump bump).

Another way to differentiate a pump bump from insertional Achilles tendonitis is by the location of the pain. This picture shows the back of a right heel, the outside of the ankle and a few of the lesser toes. The red dotted line outlines the Achilles tendon. This is the area within the tendon where we are most likely to find an acute tear of the Achilles tendon or tendonitis. The red circle shows the area where the Achilles tendon inserts into the calcaneus and is the location of chronic insertional Achilles tendonitis. This area will often become hypertrophied (enlarged) as the result of spurring that forms on the posterior heel at the insertion of the tendon. The red circle is also the area where we would find pain associated with retrocalcaneal bursitis. The blue area is on the outside, or lateral aspect of the heel. The blue area is where we would find the symptoms of Haglund's Deformity or a pump bump. You can see that a Haglund's Deformity is usually found on the posterior lateral heel (blue) while insertional Achilles tendonitis is central to the Achilles tendon.

Treatment of acute and chronic Achilles tendonitis

Knowing that the single greatest contributing factor to acute and chronic Achilles tendonitis is equinus (see the biomechanics section below for more information on equinus), we know that we need to weaken the calf muscle to allow the Achilles tendon an opportunity to heal. This can be done by elevating the heel with heel lifts or by wearing a subtle high heeled pair of shoes. Inflammation of the tendon can be calmed by ice, both before and after activities. Anti-inflammatory medications, casting or ultrasound treatment can also be used. Steroid injections are typically not used to treat Achilles tendonitis since injecting the tendon has a tendency to weaken the tendon resulting in a possible rupture.

In cases of chronic Achilles tendonitis, patients who do not respond to heel lifts and anti-inflammatory medications require a lengthening procedure of the Achilles tendon with or without a partial resection of the posterior heel. In cases with minimal hypertrophy of the heel, lengthening of the tendon will suffice. Lengthening of the Achilles tendon may be performed through three 0.5cm incisions but does require a period of casting. Full recovery may take 6-18 months. Endoscopic techniques are also available in a limited number of cases, correcting equinus with a procedure called an endoscopic gastrocnemius recession.

Cases of insertional Achilles tendonitis that fail to respond to conservative care will require partial resection of the posterior heel and lengthening of the Achilles tendon.  The following images show a Z-plasty lengthening of the Achilles tendon and resection of the posterior heel with a mallet and osteotome.  A bone anchor with attached suture is placed in the posterior heel to affix the Achilles tendon.  This procedure is performed in a hospital or outpatient surgery center and is typically performed under a general anesthetic.  Casting for 6-8 weeks following the procedure is required.

A newer method of treating chronic Achilles tendonitis (tendonosis) is called Topaz Radiofrequency Ablation. Topaz is used to stimulate an acute inflammatory reaction within the tendon. The inflammatory reaction attracts cellular and chemical mediators of inflammation and is assumed to jump start the natural healing process. Topaz surgery uses a grid of small holes that are placed in the tendon using a radiofrequency wand. The depth of the holes are varied. The indications for Topaz surgery includes those individuals who are interested in an ambulatory solution for Achilles tendonosis or who may have co-morbidities that preclude them from having an Achilles tendon lengthening.

Achilles - Greek warrior from Homer's Iliad. Hence the term Achilles is always capitalized.

Calcaneal apophysitis - see Sever's Disease.

Haglund's Deformity - See pump bump.

Peritenon - external lining of a tendon.

Pump bump - term that originated in the 1950's when many women were wearing pump high heels. Pumps were considered a contributing factor to an enlargement of the back of the heel. Pump bumps are typically found postero-lateral where as true Achilles tendonitis is posterior and specific to the insertion of the Achilles tendon.

Sever's Disease - An inflammatory disease of the growth plate of the posterior heel found in young boys. Usually seen in boys age 10 to 13 years old and during increased activities such as starting football or soccer practice. Pain with side to side compression of the heel.

TAL - tendo Achilles lengthening.

Tendonitis - refers to a group of conditions that have to do with inflammation surrounding or within the structure of a tendon. May or may not exhibit swelling.

Tendonosis - refers to a group of conditions that at one time had been inflamed but have lost the ability to mount an inflammatory response.

The Achilles tendon is the distal extension of the two muscles of the calf, the gastrocnemius and the soleus. The gastrocnemius is the longer of the two muscles and originates on the proximal side of the knee (above the knee). The soleus, or shorter muscle of the calf, originates distal to the knee joint. Combined, these muscles make up the calf. As these two muscles descend to the distal 1/3 of the leg, they combine to form the Achilles tendon. Fibers of the Achilles tendon continue beyond the insertion to form the plantar fascia on the bottom of the heel. Fibers of the Achilles tendon attach to the back of the heel below the mid-level of the body of the heel.

The Achilles tendon tends to rotate as it descends from the conjoined muscles to the heel. The rotation of the tendon is from posterior to medial so that fibers that begin on the posterior leg inset to the medial side of the heel. The anatomical function of this rotation is to invert the heel during plantarflexion of the foot.

Most tendons have a tendon sheath that produces fluid, called synovial fluid, that baths the tendon in nutrition. The Achilles tendon does not have a true tendon sheath and is merely surrounded by a structure called peritenon. Peritenon is a thin layer of fibrous tissue that separates the Achilles tendon from surrounding soft tissue. The absence of a true tendon sheath presents with both an advantage and a disadvantage for the Achilles tendon. Most tendon sheaths are fixed to an adjacent structure such as bone. The absence of the tendon sheath allows the Achilles tendon to complete a larger range of motion. The absence of a tendon sheath also limits the amount of circulation and synovial fluid that can be supplied to the tendon when injured. This small fact accounts for much of the reason why Achilles tendon ruptures heal so poorly.

Equinus is the most common contributing factor to Achilles tendonitis. Equinus, derived from the term equine or horse, refers to one who walks on their toes. Equinus can determined by measuring the range of motion of the ankle with the knee flexed and extended. When the knee is flexed, the amount of equinus of the soleus muscle is measured. With the knee extended, both the soleus and gastrocnemius muscles are measured. 

To measure equinus, imaginary lines are established on the long axis of the leg and the foot. By dorsiflexing the foot (moving the toes towards the leg) an angular measurement is established between these two lines. Normal range of motion of the ankle, to complete a normal gait cycle, is 10 to 15 degrees beyond 90 degrees. This means that the normal range requires the ankle to dorsiflex to 90 degrees plus an additional 10 to 15 degrees. An inability to complete this range of motion is termed equinus.

Other factors may contribute to an inability to reach 90 degrees, such as a bony block on the front of the ankle.

Acute Achilles tendonitis

Acute Achilles tendonitis has a abrupt onset with pain 2-3 cm proximal to its' insertion on the back of the heel. Most individuals with acute Achilles tendonitis can describe an injury or single event that initiated the pain. Symptoms of acute Achilles tendonitis occur at the beginning of an activity and are described as a sharp pain. As the activity progresses, the pain decreases for a period of time. With excessive use, the tendon again becomes painful at the end of activity. For example, runners with Achilles tendonitis experience pain as they begin their run. The pain subsides during their run only to recur near the end of their normal running distance.

Chronic Achilles tendonitis

Chronic Achilles tendonitis exhibits the same type of pain as acute Achilles tendonitis but the location of the pain is usually at the insertion of the Achilles tendon into the heel. Chronic Achilles tendonitis can also cause hypertrophy (enlargement) of the posterior heel. Chronic Achilles tendonitis does not improve with use, but rather show a direct relationship with the duration of time spent on your feet; the more you use it, the more it hurts.

Achilles tendon, partial rupture

Gout - deposition of monosodium urate crystals (hyperuricemia)

Retrocalcaneal bursitis (Albert's Disease) - this is the formation and inflammation of a bursa at the back of the heel between the heel bone and Achilles tendon

Rheumatoid arthritis

Septic Arthritis

Sero-negative arthropathies such as Reiter's Syndrome

Sever's Disease - and inflammatory condition typically found in young over weight boys age 10 to 15 years old

Shepard's fracture - fracture of the posterior tubercle of the talus.

Stress fracture of the calcaneus - Achilles tendonitis pain is characteristically different from that of fractures of the calcaneus. Fracture pain begins with the onset of activity and remains painful through the activity. Tendonitis, on the other hand, hurts at the onset of activity, subsides during the activity only to recur at the end of activity. These symptoms may vary in every case and are only referenced in and effort to differentiate symptoms.

Tarsal Tunnel Syndrome - also known as posterior tibial nerve neuralgia. Tarsal Tunnel Syn. characteristically has pain that does not decrease with rest. Also has numbness or 'tingling' of the toes

• Calcaneal Fractures

• Bursitis

• Achilles Tendon Rupture

• Equinus

• CT Band Syndrome

This article was written by Jeffrey A. Oster, DPM, and last updated 2/5/13.