Achilles tendinopathy is an irritation of the Achilles tendon, a thick band of tissue along the back of your lower leg that connects your calf muscle to your heel. The Achilles tendon helps balance forces in your leg. Tendinopathy refers to any problem with the tendon and can be a long-term or short-term issue. This condition results when the demand placed on the Achilles is greater than its ability to function, which can happen after an injury or repetitive irritation.
The severity of acute injuries is graded based on the amount of damage to the tendon. Grade I injuries are mild strains and disruption of a few fibers, which causes mild to moderate pain, tenderness, swelling, and stiffness. Grade II injuries are moderate strains and disruption of several fibers, which causes moderate pain, swelling, and difficulty walking. Grade III injuries are complete ruptures of the tendon, often characterized by a popping sound, immediate pain, and inability to bear weight. Grade III injuries typically require surgery to repair.