Isolated femoral avulsion fracture at the medial head of the gastrocnemius muscle in a skeletally immature gymnast.

Avulsion fractures of the medial head of the gastrocnemius muscle are extremely uncommon, with only a few cases documented in medical literature. We present a case involving a 12-year-old female gymnast who experienced acute pain in the back of her knee after a training incident. Initial radiographs did not reveal any abnormalities, prompting further imaging for accurate diagnosis. Advanced imaging identified an avulsion fracture at the posteromedial aspect of the femur, originating from the medial gastrocnemius tendon. The patient underwent conservative treatment. At the three-month follow-up, she had returned to gymnastics without any symptoms. At the two-year follow-up, she remained asymptomatic and had fully resumed her pre-injury level of athletic performance.