Ankle Injuries: Achilles Tendon Injuries
The Achilles tendon is a strong tendon that connects the calf muscles to the heel. The calf is formed by two muscles: the underlying soleus muscle and the thick outer gastrocnemius muscle. When they contract, the pull on the Achilles tendon causes the foot to point down (plantar flexion) and to rise up onto the toes. This powerful muscle group helps when you sprint, jump, or climb.
With aging and overuse, the Achilles tendon is subject to degeneration within the substance of the tendon. The term degeneration means that wear and tear occurs in the tendon over time and leads to a weakening of the tendon. Degeneration in a tendon usually shows up as a loss of the normal arrangement of the fibers of the tendon. Tendons are made up of strands of a material called collagen (think of a tendon as similar to a nylon rope with the strands of collagen being the nylon strands). Some of the individual strands of the tendon become disorganized due to the degeneration, other fibers break, and the tendon loses strength. The healing process in the tendon can cause the tendon to become thickened as scar tissue tries to repair the tendon. This process can continue to the extent that a nodule forms within the tendon. This condition is called tendinosis. The area of tendinosis in the tendon is weaker than normal tendon and is usually painful.
Spontaneous rupture of the Achilles tendon can occur in patients in their 20's to 40's. Rupture is more common in men than women and most injuries occur during sporting activities. The most common mechanism of injury is pushing off forcefully such as in tennis, squash, racquetball, and basketball.
When the Achilles tendon ruptures, the person often hears a "pop" or "snap" at the time of injury and feels a sudden pain in the region of the Achilles tendon. However, the pain subsides quickly. There is weakness when trying to stand on tiptoes. A defect or gap in the Achilles tendon can usually be felt.
X-rays are useful to rule out fractures, but are of limited value to diagnose Achilles tendon ruptures. Although MRI will show the ruptured tendon, it is usually not necessary to obtain an MRI because the diagnosis is obvious during examination.
If the foot and ankle are immobilized in a cast with the toes pointing down for 8 weeks the torn Achilles tendon can heal. Non-surgical treatment avoids potential complications associated with surgery, such as infections and wound breakdown. However, there is a higher re-rupture rate with cast treatment, there is less pushing-off strength and less endurance when compared to tendons that have been surgically repaired.
Surgical repair of Achilles tendon ruptures consists of sewing together the torn ends. Sometimes, if the injury is chronic or the tissue is poor, local tissue such as tendon grafts or fascia can be used to reinforce the repair it.
A major advantage of early repair is that early range of motion out of cast can be allowed.
Surgical repair of the Achilles tendon offers a lower re-rupture rate (0-4%), a greater chance of returning to sports, greater strength, and more endurance.
Post-operative rehabilitation consists of a cast for two weeks, then a removable cast-boot for about 8 weeks after surgery. It usually takes six months after surgery before sports activities can be resumed.