Achilles Tendon Injuries

The Achilles tendon is the strongest in the body. The thick band of fibrous tissue connects the calf muscles to the heel bone at the back of the leg.  Often referred to as the “heel cord,” this tendon is essential for everyday movement—especially walking, climbing stairs, and pushing off during running or jumping.
 
Achilles tendon injuries exist on a continuum of degeneration. Achilles tendonitis represents the acute inflammatory phase, often triggered by a sudden increase in activity or repetitive stress; symptoms at this stage are typically short-term but can be painful and limiting. If this inflammation is not addressed correctly, it may progress to Achilles tendinosis, a chronic degenerative condition in which the tendon fibers lose their normal structure, weaken, and may develop microscopic tears. 

With severe or prolonged tendon damage, advanced degeneration or rupture can occur, resulting in partial or complete tearing of the tendon—sometimes even without intense pain. Understanding where you fall on this continuum is essential for determining the most appropriate treatment plan.

Achilles tendonitis and tendinosis are primarily considered “overuse” disorders, often developing after a sudden increase in repetitive activities that place excessive strain on the tendon. Over time, this strain causes micro-injuries within the tendon fibers, which can progress to microscopic tears. When the tendon is not given adequate time to recover between activities, the tissue weakens and undergoes structural changes, eventually leading to chronic pain and dysfunction. In response to these repeated injuries, the body attempts to heal the damaged tissue by triggering inflammation, swelling, and thickening of the tendon, forming a dense collagen layer—or a “collar”—around the injured area.
 
Insertional heel pain (Haglund's condition), a related condition, occurs where the Achilles tendon attaches to the back of the heel bone. This area is particularly vulnerable to irritation from repetitive stress, tight calf muscles, or activities involving frequent uphill running or jumping. In insertional conditions, the tendon fibers and surrounding tissues may become inflamed or degenerated at the point of attachment, sometimes accompanied by bone spurs that worsen discomfort.
 
Athletes are at heightened risk for Achilles disorders of all types, but these injuries are also common in individuals whose occupations require repetitive loading of the feet and ankles. “Weekend warriors” who participate in sporadic high-intensity activities without regular conditioning are similarly susceptible. Additionally, individuals with excessive pronation (flattening of the arch) place increased strain on the Achilles tendon with every step, making them more vulnerable to tendonitis, tendinosis, and insertional heel pain. Poorly supportive or worn footwear can further compound these biomechanical stresses, accelerating the onset or progression of symptoms.

• Pain: Ranging from aching and stiffness to soreness or tenderness, along the tendon’s course. This discomfort can manifest anywhere from the tendon’s attachment just above the heel to the region below the calf muscle. Pain often intensifies in the morning or after periods of rest, improves somewhat with movement, but worsens with increased activity.
• Tenderness: Or occasionally intense pain when squeezing the sides of the tendon. Direct pressure on the back of the tendon may be less painful.
• Enlarged Nodules: In cases of degeneration, the tendon may enlarge and develop nodules in the damaged area.

Diagnosing Achilles tendonitis, tendinosis, insertional heel pain, or a potential tendon rupture begins with a comprehensive examination of the foot and ankle, including an assessment of swelling, tenderness, range of motion, and tendon integrity. In cases of suspected rupture, our specialists may perform specific clinical tests to evaluate tendon continuity. X-rays, ultrasound, or MRI imaging may also be used to further assess the severity of the injury, identify tendon degeneration or tearing, and guide the most appropriate treatment plan.