Muscle ruptures in the form of hamstring avulsions have been reported more frequently in the younger population due to an immature epiphyseal growth plate found on the ischial tuberosity in older children and adolescents. Hamstring avulsions in adults with fully fused ischial tuberosities are contributed to be ruptures of the proximal hamstring tendon or complete avulsion fractures of the ischial tuberosity.  

An immediate diagnosis following proper treatment methods for ischial tuberosity avulsions or tendon ruptures is essential at this point because several individuals whom were treated non-operatively for hamstring ruptures experienced residual loss of power. Further complications for hamstring avulsions include pain, weakness, cramping during locomotion and pain while sitting. As with the majority of tendon avulsions, treating the injury as soon as possible can present better outcomes than delaying treatment. According to research, receiving treatment within four weeks of injury resulted in better recovery outcomes as compared to those which received treatment after four weeks of injury.

Hamstring Anatomy and Biomechanics

The hamstring muscles consist of the biceps femoris, both the long head and the short head, the semitendinosus and the semimembranosus. All of these muscles, excluding the biceps short head, attach onto the ischial tuberosity. The short head biceps begin along the femur simultaneously with the linea aspera.

At the proximal origin, the long head of the biceps and the semitendinosus form a combine to create the tendon which attaches to the ischial tuberosity and the semimembranosus.

When an individual undergoes puberty, a secondary ossification center at the ischial tuberosity develops without fusing until the individual’s late teens or early twenties. Within the period of time between the fusion of the apophysis, an increased force traction may cause a hamstring avulsion along the apophysis as a result of a weakened connection between the bone and the muscle. After the bones begin to mature, injuries at the myotendinous junction become more common.