Hamstring injuries are common in athletes who participate in sports activities such as track, football, and basketball that involve running. The three hamstring muscles namely semitendinosus, semimembranosus and biceps femoris are at the back of the thigh and help you bend (flex) your knee and extend your leg.
Injuries to the hamstring group of muscles can range from a minor strain to a complete tear. Avulsion injury occurs when the hamstring muscle tendon completely tears away from the bone. Sometimes, the tendon or ligament may even pull off a piece of bone along with it. Tears from the pelvis are known as proximal hamstring avulsion.
Hamstring tendon avulsions are caused by a sudden contraction of the hamstring muscle during strenuous exercise. A sudden jump, overstretch, or large sudden load to the muscle can increase your risk of hamstring avulsion injury.
Patients with hamstring avulsion injury will experience extreme pain, weakness, cramps while walking and running, and poor leg control, particularly while walking down a slope.
Hamstring avulsions occur rarely and are often difficult to differentiate from simple strains. Diagnosis is made through the symptoms and physical examination. During the physical examination, your doctor will examine your thigh for tenderness and bruising as well as check for signs of pain, swelling and weakness in the back of your thigh. Your doctor may order an X-ray to see whether the avulsed tendon has pulled away a small piece of bone and MRI scan to determine the severity of your injury.
Initial treatment for hamstring injuries involves rest, ice, compression, and elevation (RICE protocol); all assist in controlling pain and swelling.
Hamstring avulsion is a serious injury that may require surgery. During the tendon avulsion repair, hamstring muscles are pulled back to its normal attachment. Your surgeon cuts away any scar tissue from the hamstring tendon and then the tendon is reattached to the bone using staples or stitches. If there is a complete tear within the muscle, the torn ends are reattached using stitches.
After surgery, you may need to use crutches and a brace to protect and keep your hamstring muscle in relaxed position. Your doctor will recommend physiotherapy, which involves gentle stretching exercises in order to restore normal function. Rehabilitation period of at least 6 months may be needed before returning to athletic activities.