Common Conditions of the Achilles Tendon -- American Family Physician

www.aafp.org/afp AMERICAN FAMILY PHYSICIAN 1805 increased activity. The morphologic changes such as decreased cell density, decreased collagen fibril density, and loss of fiber waviness that occur with aging predispose the tendon to injury. The normal gait cycle requires extreme motion from within the ankle. With each step, the subtalar joint typically moves 30 degrees (inverts 20 degrees, everts 10 degrees). This movement results in repetitive lengthening and shortening of the Achilles tendon complex. Running and jumping further increase the load on the Achilles tendon. Tendons that transmit large loads under these conditions are subject to injury. Extreme shear forces across the tendon complex are believed to cause prolonged loading of the tendon, resulting in microtrauma and inflammation. Common conditions of the Achilles tendon include tendonitis, peritendonitis, tendinosis, rupture, and retrocalcaneobursitis. These conditions are usually caused by overuse and can occur in adolescents and adults (Table 1). Achilles tendon injuries are increasing in prevalence as physical activity becomes more common, especially in older patients. Men older than 30 years are particularly vulnerable to injuries of the Achilles tendon, but persons beginning a sport or increasing activity levels are also at risk. T he Achilles tendon spans two joints and connects the calcaneus to the gastrocnemius and soleus muscles, comprising the largest and strongest muscle complex in the calf (Figure 1). The tendon is vulnerable to injury because of its limited blood supply, especially when subjected to strong forces. The blood supply to the tendon is provided by longitudinal arteries that run the length of the muscle complex. The area of the tendon with the poorest blood supply is approximately 2 to 6 cm above the insertion into the calcaneus. The blood supply diminishes with age, predisposing this area of the tendon to chronic inflammation and possible rupture. The Achilles tendon does not have a true synovial sheath but instead has a paratenon. The paratenon is a connective tissue sheath that surrounds the entire tendon and is able to stretch 2 to 3 cm with movement, which allows maximal gliding action. The Achilles tendon has been shown to thicken in response to The Achilles tendon, the largest tendon in the body, is vulnerable to injury because of its limited blood supply and the combination of forces to which it is subjected. Aging and increased activity (particularly velocity sports) increase the chance of injury to the Achilles tendon. Although conditions of the Achilles tendon are occurring with increasing frequency because the aging U.S. population is remaining active, the diagnosis is missed in about one fourth of cases. Injury onset can be gradual or sudden, and the course of healing is often lengthy. A thorough history and specific physical examination are essential to make the appropriate diagnosis and facilitate a specific treatment plan. The mainstay of treatment for tendonitis, peritendonitis, tendinosis, and retrocalcaneobursitis is ice, rest, and nonsteroidal anti-inflammatory drugs, but physical therapy, orthotics, and surgery may be necessary in recalcitrant cases. In patients with tendon rupture, casting or surgery is required. Appropriate treatment often leads to full recovery. (Am Fam Physician 2002;65:1805-10. Copyright© 2002 American Academy of Family Physicians.) Common Conditions of the Achilles Tendon