Achilles tendonitis refers to a spectrum of disease ranging from nonpainful nodules to painful swelling of the tendon and paratendon sheath. It most typically develops from overuse, usually after sudden changes in activity or training level. It often occurs in older recreational athletes, who are generally more sedentary and deconditioned. Multiple factors contribute to the condition, including inappropriate footwear, training on poor surfaces, or prolonged running or jumping. High-risk factors include anatomic abnormalities, such as cavus feet, tibia vara, and heel or forefoot varus deformities. A tight Achilles tendon may develop in patients who frequently wear high-heeled shoes.
The most common area of pain is typically 2 to 6 cm proximal to the insertion site. This is due to a relative paucity of blood vessels in that region, making it more susceptible to inflammation and degeneration from repetitive microtrauma. Pain and tenderness increase with dorsiflexion of the foot. In some cases, a tendon friction rub may be palpable.
Management and Disposition
Careful examination should be performed to distinguish between Achilles tendonitis and tendon rupture. The Thompson test (see Achilles tendon rupture) and palpation of the tendon for gaps or discontinuity should be performed. Ultrasound can also be used. Any patients with suspicion of partial or complete tendon rupture should be splinted and urgently referred to orthopedic surgery. In cases of tendonitis, gentle progressive stretching and lengthening exercises are helpful. In athletes, a reduction in activity is recommended. Use of gel heel inserts may be helpful in the short term, by cushioning and raising the heel, thereby decreasing tendon excursion. Use of ice and NSAIDs is useful in reducing pain and inflammation.
Fluoroquinolone use has been reported to increase the risk of Achilles tendonitis and possible rupture. Patients presenting with pain, who are currently taking a fluoroquinolone, should have alternative antibiotic therapy considered.
Corticosteroid injection for Achilles tendonitis is very controversial and should not be performed in the emergency department.
Bilateral tendon involvement, especially at the insertion site, suggests a systemic inflammatory condition such as ankylosing spondylitis, reactive arthritis (Reiter syndrome), or psoriatic arthritis.
Achilles Tendonitis. Note the significant erythema and thickening of the Achilles tendon on the patient’s left compared to the unaffected right side. (Photo contributor: Kevin J. Knoop, MD, MS.)