In this study, 41 cases of hamstring avulsion are reviewed. The hamstring muscle is along the back of the thigh. There are three main parts: the biceps femoris, semimembranosus, and semitendinosus. Avulsion means the tendon has torn completely away from the bone.
The cause, mechanism of injury, and symptoms are presented. Surgical technique for reattaching the muscle is described. Sometimes there wasn’t enough tissue to work with. A tendon graft from the iliotibial band (or tract) was harvested from the same side. The iliotibial tract is a layer of fibrous fascia along the outside of the thigh.
Results of surgical treatment are the main focus of outcomes in this study. Acute cases (early surgery) were compared to patients treated in the chronic phase (surgery was months to years later).
Results for each patient were rated as excellent (no symptoms/normal function), good (mild symptoms/normal activity), moderate (painful symptoms/loss of function), and poor (function impaired by significant symptoms).
Most of the athletes in the study had excellent or good results. Two-thirds were able to return to their preinjury levels of sports activities after surgery. A delay in having surgery was linked with a poor result. Patients with delays greater than six months had the worst results.
The authors recommend immediate surgery for acute cases of hamstring avulsion. Nonoperative care is usually unsuccessful. The delay in surgery can mean a poor result. With delays, scar tissue and adhesions form.
Scarring and adhesions can wrap around the sciatic nerve. Sciatica with pain and numbness in the buttock and down the leg may develop. Muscle weakness and atrophy can occur. The hamstring tendon retracts and can’t be pulled back in place to reattach it. The sciatic nerve can get entrapped inside the retracted muscle. When any of these things happen, there can be irreversible damage to the nerve. The surgery is more complex. A tendon graft may be needed.
The good news is that even with delays in surgery, patients can have a good result after repair of a hamstring avulsion. Athletes are able to return to their sport at a level equal to their preinjury level of participation. Carefully following the surgeon’s directions and completing a rehab program can yield considerable improvements (even years later).