Evaluation of Hamstring Injuries: The Role of Magnetic Resonance Imaging

Hamstring injuries are quite common among professional football players and can have a significant effect on the time lost as a result of the injury. The reported recurrence rate of hamstring strain is between 30% and 40%. Along with history and physical examination, magnetic resonance imaging (MRI) scan is very useful in not only confirming the diagnosis, but it can also guide to predict recovery time. The recovery time varies with the site, cross-sectional area, and longitudinal extent of the injury. The more proximal and larger the tear, the longer it takes to recover. Patients with an initial injury around cross-sectional area of more than 50% of the muscle circumference and an initial length of the injury greater than 60 mm are at increased risk of a repeat injury. Occasionally, the radiologic changes in the hamstring muscles can be present on MRI even after 6 weeks after the initial injury. MRI scan appears to be less helpful in minor injuries in comparison with more severe injuries.