The Achilles tendon is the single strongest tendon in the human body. The primary function of the Achilles tendon is to transmit force from the calf to the foot enabling walking and running. A tear or rupture of the Achilles tendon can be partial or complete. Partial rupture of the Achilles can also be broken down into micro or longitudinal tears.

Smaller, partial tears of the Achilles tendon are called micro tears. Micro tears are one to several millimeters in length. Micro tears can be single or multiple in number. Longitudinal tears are larger tears that are micro tears that propagate to a larger tear. Longitudinal tears can be as small as a centimeter and be as large as several centimeters in length. Longitudinal tears dissect the length of the Achilles tendon, paralleling the fibers of the tendon. MRI is used to determine the presence of a tear and whether the tear is a micro tear or a longitudinal tear.

A complete rupture of the Achilles tendon can be a debilitating injury. The actual rupture of the tendon is described by most patients as feeling as if they were hit in the back of the leg. An audible pop is often described. Most ruptures occur 2-4cm proximal to the insertion of the tendon into the calcaneus (heel bone). Many patients who sustain a complete rupture of the Achilles tendon describe a long period of chronic Achilles tendonitis leading up to a complete rupture. Other factors that contribute to a complete tear of the Achilles tendon include the use of steroids (oral and injectable), fluoroquinolone antibiotics (Levaquine, Cipro), advanced age and diabetes.

Repair of Achilles tendon ruptures may be conservative or surgical. Orthopedic and podiatric literature abounds with articles that compare the merits of conservative vs. surgical care. Re-rupture of the tendon is not uncommon regardless of the method of correction. Statistically, patients who do undergo surgical repair of an Achilles tendon rupture do have fewer incidences of re-rupture. These findings may also reflect the nature of patients that would be considered a good surgical candidate. Typically we would assume that those patients who are in poor health (e.g. elderly, diabetic, immune compromised) would not become surgical candidates. Therefore, good surgical candidates may generally be more healthy and be more prone to heal regardless of the method of treatment.

Conservative care for Achilles tendon ruptures includes 10-12 weeks casting in a slightly plantar flexed position. Plantarflexion is the position that occurs as the toes move away from the shin. This position takes tension off of the Achilles tendon to allow proper healing. Casting can be performed in a serial manner with less plantarflexion in each cast as the patient heals. Follow-up in a walking cast with an elevated heel is common. Also, physical therapy is often employed following casting to regain strength and flexibility.

Surgical care has been traditionally performed with open (vs. small incision or endoscopic) techniques. Repair of a ruptured Achilles tendon is performed with the patient in a prone position with general anesthesia. The damaged ends of the tendon are 'freshened' and stitched together. A special stitch called a Bunnell suture is used that employs a criss-cross of stitches to prevent tear-out of the suture. Surgical repair may be augmented with the use of fibrin glue or autogenous growth factor. Graft Jacket (Wright Medical), an autologous graft material, can also be used to supplement defects in the length of the tendon. Surgical correction is always followed with non-weight bearing casting for 6-8 weeks.

Recent articles have advocated a surgical approach for repair of ruptured Achilles tendons that employs both an open and percutaneus technique of repair. The most popular method was described by M. Kakiuchi of The Osaka Police Hospital in 1995. This technique involves the use of an open procedure at the site of rupture to enable debridement of the ruptured tendon. Kakiuchi also employs a closed technique to suture the tendon to allow for proper healing.

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.

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.

Tendo Achilles - refers to the Achilles tendon.

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.

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 and is often a precursor to Achilles tendon ruptures. 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. Imaginary lines are established on the long axis of the leg and the foot. By dorsiflexing the foot (toward the body) 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.

Partial Achilles tendon rupture

Symptoms of a partial Achilles tendon rupture have either an insidious or abrupt onset with pain and swelling 2-3 cm proximal to the insertion of the Achilles tendon on the back of the heel. Swelling is described as fusiform, or tubular often surrounding the entire body of the tendon.  Pain with direct palpation of the tendon is also common.  Most patients with a partial rupture of the Achilles tendon cannot describe an injury or single event that initiated the onset of pain. Symptoms of partial Achilles tendon tears occur at the beginning of an activity and are typically described as a sharp pain in the tendon. As the activity progresses, the pain may decrease for a period of time. With excessive use, the tendon again becomes painful at the end of activity. For example, runners with partial Achilles tendon tears experience pain as they begin their run. The pain subsides during their run only to recur near the end of their normal running distance.

Complete Achilles tendon rupture

The onset of a complete Achilles tendon rupture is abrupt and often described as a pop or snap in the back of the ankle.  An audible, unilateral pop is described.  Patients with a complete tear of the Achilles tendon are unable to raise up on their toes or push off at the toe off phase of gait.  A Thompson test is used to evaluate a suspected torn Achilles tendon.  With the patient lying prone, the calf is squeezed.  If the patient has an intact  Achilles tendon, the foot will plantarflex.  This is called a negative Thompson sign.  If the calf is squeezed and the foot does not plantarflex, this indicates a positive Thompson's sign and torn Achilles tendon.  The Thompson sign can also be performed using a blood pressure cuff.  The cuff is placed around the calf and inflated to 100mm/hg.  With an intact Achilles, dorsiflexion of the foot will increase pressure in the calf to 140mm/hg.  No increase in the reading of the cuff suggests a positive Thompson sign and complete rupture of the Achilles tendon.

Differential diagnoses for partial Achilles tendon ruptures -

Calcaneal stress fracture - 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.

Gout - deposition of monosodium urate crystals (hyperuricemia).

Posterior tibial tendonitis - also known as PTTD or posterior shin splints.

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.

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

• Achilles Tendonitis

• Calcaneal Fractures

• Equinus

• CT Band Syndrome

• Ankle Pain

This article was written by Jeffrey A. Oster, DPM and last updated 4/28/10. Additional references include;

1. Hattrup, S. , Johnson, K.A., A review of ruptures of the Achilles tendon. Foot and Ankle 6:34, 1985
2. Fierro, N., Sallis, R., Achilles tendon rupture, is casting enough?. Post. Grad. Med. 98:145, 1995
3. O'Brien, T. the needle test for complete rupture of the Achilles tendon. J. of Bone and Joint Surg. 66-A(7):1099-1101, 1984
4. Bradley, J., Tibone, J., Percutaneus and open surgical repairs of Achilles tendon ruptures, a comparative study. Am. J. Sports Med. 18:188, 1990
5. Wills, C., Washburn, S., Caiozzo, V., Prietto, C. Achilles tendon rupture; a review of the literature comparing surgical vs. non-surgical treament. Clin. Orthop. 207:156. 1986
6. Dananberg HJ, Shearstone J, Guiliano M: Manipulation method for the treatment of ankle equinus. JAPMA 90:8 2000
7. Rebeccato A, Santini S, Salmaso G, Nogarin L: Repair of the Achilles Tendon Rupture: A Functional Comparison of Three Surgical Techniques. JFS 40:4 2001
8. Kakiuchi M. A combined open and percutaneus technique for repair of tendon Achilles. JBJS. 77-B:60-63, 1995
9. Hohendorff B, Siepen W, Spiering L, Staub L, Schmuck T, Boss A. Long term results after operatively treated Achilles tendon rupture: fibrin glue vs suture. J Foot Ankle Surg, 47:5, 392-399 2008
10. Ibrahim, S. Surgical Treatment of Chronic Achilles Tendon Rupture. J Foot Ankle Surg, 48:3,340-346, 2009