Achilles Tendonitis

Connective tissue that connects a muscle to a bone is called a tendon. The tendon serves to transmit forces from the muscle to a bone; hence, it is no surprise that it receives the greatest tension during movement. In fact, it is subjected to twice the tension of a muscle during contraction. Injuries in the junction between muscles and tendon are a common area of musculoskeletal injury. The Achilles tendon, a tendon that connects the calf muscle to the heel bone, is one of the most commonly injured tendons.

What causes Achilles tendonitis? 

Achilles tendonitis is usually a chronic injury caused by repetitive microtrauma  injury that causes breakdown of the collagen fibers. This usually occurs in combination with inflexibility of the tendons itself or the hamstring muscles, flat foot, and biomechanical deficits such as excessive rolling of the foot outward (hyper pronation). Age is also a risk factor because the tendons become stiff and weak as we age.

How do I suspect Achilles Tendonitis?

Achilles tendonitis will cause chronic pain near the heel or behind the ankle. Pain becomes worse with activities that require pushing the feet off the floor such as walking and running. This may be accompanied by swelling near the area of pain and tenderness. A doctor usually performs a Thompson’s test to determine possibility of tendon rupture. A positive test will show absence of foot movement when the belly of the calf muscle is squeezed while a patient is lying face down with feet off the edge of an examination table. This indicates Achilles tendon tear instead of tendonitis.

Do I need to undergo special tests such as X-ray?

Imaging is usually not required. In cases where diagnosis is in question, both magnetic resonance imaging and musculoskeletal ultrasound can provide confirmation of injury. Both imaging techniques will show collagen disorientation, microscopic tearing, and inflammatory changes within the injured tendon.

Treatment

• Non-steroidal Anti-inflammatory Drugs (NSAIDs)

NSAIDs reduce inflammation and pain by disrupting production of inflammatory cells. They are often prescribed for a short duration to reduce possible side effects in the kidneys, stomach, and heart. NSAIDs are often prescribed to decrease pain in preparation for rehabilitation program participation.

• Relative rest and activity modification

Relative rest from athletic activities is prescribed to facilitate proper healing of the tendon. Training methods are modified to ensure that intensity and duration of training are adjusted gradually to allow the tendons to adapt to stress appropriately. Part of activity modification includes inspection of other joints such as the knee and hips for possible biomechanical defects. A defect in these areas can lead to Achilles tendonitis since joints move in unison. Other parts will have to work extra to compensate for the defective part.

• Rehabilitation

Rehabilitation includes stretching and strengthening of the calf muscles. Stretching of the calf muscles is very important because chronic inflexibility of tendons is often the cause of tendonitis. Strengthening of the calf muscles also prepare the tendon for explosive activities and prevent flat foot.  Weak hip and knee muscles are also strengthened to prevent recurrence of tendonitis. 

• Heel Lifts

Heel lifts keep the foot in a slight tiptoe position that allows rest by decreasing the stretch placed on the Achilles tendon. It is used on a short-tem basis (a few weeks) only to avoid risk of contracture.

• Ultrasound guided platelet-rich plasma (PRP) injection

Musculoskeletal ultrasound guided PRP injections are now used to treat Achilles tendonitis. A PRP procedure involves drawing blood from the patient. The extracted blood is placed in a centrifuge until the plasma is separated from red blood. The plasma is mixed with fibrin in order to activate growth factors that promote healing. The PRP is then injected into the affected site with the aid of an ultrasound. Immobilization for one week allows healing of the tendon before engaging in a rehabilitation program. Corticosteroids are not part of the treatment for tendonitis because it weakens tendon structure that can lead to rupture.