The Achilles tendon is the largest and strongest tendon in the human body, connecting the calf muscles and the heel bone. This structure facilitates the push-off motion required for walking, running, and jumping. An Achilles rupture is a serious injury where this thick cord tears, either partially or completely separating the tendon ends. This injury occurs suddenly, leading to immediate functional loss in the lower leg.
Understanding the Achilles Tendon and Rupture
The Achilles tendon is formed by the gastrocnemius and soleus muscles (the triceps surae), which insert onto the calcaneus, or heel bone. Its primary function is to enable plantarflexion, the movement that points the foot downward. Despite its strength, the tendon is susceptible to injury during sudden, forceful movements that place an eccentric load on the structure.
Most ruptures occur in the watershed zone, typically located two to six centimeters above the heel bone, rather than at the point of insertion. This region has a naturally lower blood supply, which can predispose it to degeneration and failure under high strain. A common mechanism for rupture is a sudden, unexpected dorsiflexion of the foot while the calf muscle is actively contracting, such as during a rapid stop or push-off.
Recognizing the Acute Symptoms
When an Achilles rupture occurs, individuals often report an immediate, distinct sensation, described as a loud “pop” or “snap” originating from the back of the ankle. This event is frequently accompanied by the feeling of being forcefully struck or kicked in the back of the leg. Following the initial event, the sharp pain is often replaced by a dull ache, swelling, and bruising in the lower calf and heel area.
A significant consequence of the injury is a sudden loss of function, specifically the inability to powerfully push off the foot. Patients with a complete rupture cannot stand on their toes on the injured side because the connection between the calf muscles and the heel has been severed. This functional impairment results in a noticeable change in gait, making normal walking difficult. In some cases, a visible and palpable gap can be felt where the tendon has separated.
Clinical Diagnosis and Initial Triage
Healthcare professionals begin the diagnostic process with a physical examination, assessing the patient’s symptoms and the mechanism of injury. The most definitive clinical test is the Thompson Test, performed with the patient lying face down and their feet hanging freely. The clinician squeezes the calf muscle; in a healthy ankle, this action causes the foot to plantarflex. If the Achilles tendon is ruptured, however, the foot will remain still.
Imaging studies are used to confirm the diagnosis and determine the extent of the damage, which is crucial for treatment planning. Ultrasound provides a dynamic, real-time view of the tendon and accurately measures the gap size between the tendon ends. Magnetic Resonance Imaging (MRI) offers a detailed look at the soft tissues, distinguishing between a partial tear and a complete rupture. Initial triage involves considering the patient’s age, activity level, and the measured size of the tendon gap.
Overview of Management Options
The two main strategies for managing an acute Achilles rupture are non-surgical (conservative) treatment and surgical repair.
Non-Surgical Management
Non-surgical management involves immobilizing the ankle in a cast or specialized walking boot. Treatment starts with the foot pointed downward to bring the tendon ends closer together. The ankle angle is then gradually adjusted to a neutral position over several weeks to allow natural healing. This approach avoids surgical risks but carries a greater risk of re-rupture, which can be as high as 10 to 15 percent.
Surgical Repair
Surgical repair involves making an incision to directly stitch the two torn ends of the tendon back together using strong sutures. This option is favored for younger, highly active individuals because it provides a more robust repair, lowering the re-rupture rate to approximately two to five percent.
Regardless of the chosen path, all patients proceed to a structured physical therapy program after the immobilization phase to restore strength and range of motion.