The Achilles tendon is the body's thickest and strongest tendon; it is composed of fibers of the gastrocnemius and soleus muscles. The tendon starts in the middle of the calf and internally rotates 90 degrees so that the soleus portion is medial distally. The tendon insertion is in the middle one-third of the posterior aspect of the calcaneus tuber.
The Achilles tendon does not have a synovial sheath that is typical for most tendons; however, it does have a paratenon that helps promote gliding during activity. The tendon remains mostly hypovascular, especially in the classic watershed area (3–6 cm proximal to insertion), but the paratenon is highly vascular.
The Achilles tendon, along with the gastrocnemius and soleus muscle complex, crosses three joints in the lower extremity. It participates in knee flexion, ankle flexion, and subtalar inversion. The tendon load has been reported to be as high as 12.5 times a person's body weight during running. This puts the tendon at risk for injury.
Achilles tendon pathology is often seen in both the athlete and patients who are less active, with obesity being a major contributor. Achilles tendon conditions involve a combination of inflammation and degeneration, including insertional Achilles tendinopathy, Achilles paratenonitis, and retrocalcaneal bursitis.
The pain from Achilles tendonitis usually begins with a mild aching sensation in the back of the heel or lower leg. Pain can be increased with exercise or certain activities, ie, climbing stairs or sprinting. An overuse injury can also precipitate symptoms, as well as improper shoe gear.
When insertional Achilles tendonitis is suspected, the lateral foot radiograph can show posterior bone spurs off the calcaneus or calcifications within the Achilles tendon (Figure E5–5). MRI and ultrasonography can provide more information regarding the level of disease within the substance of the tendon.
Achilles calcific tendonitis. (Used, with permission, from M. Dini, DPM.)
Initial conservative management should consist of nonsteroidal anti-inflammatory drugs, ice, rest, or activity modification. In combination with shoe gear modification, patients may benefit from an orthosis to help control hyperpronation, which often is a contributing factor. In patients with insertional Achilles tendinopathy, shoes that do not cause frictional pain are helpful in reducing symptoms. Physical therapy is beneficial, especially when strengthening, stretching, proprioception, and anti-inflammatory modalities are used in combination. Heel lifts are helpful in reducing the load on the Achilles during daily ...