Avulsion Fracture of the Medial Head of the Gastrocnemius Muscle Associated with Posterior Dislocation of the Knee

Case: We present an extremely rare case of an avulsion fracture of the medial head of the gastrocnemius muscle associated with posterior dislocation of the knee. The patient was a fifty-one-year-old man who was hit by a car while riding a motorcycle. The avulsed fragment was reduced and fixed with a screw, which resulted in maintenance of joint reduction despite residual instability due to the multiligamentous injuries. Conclusion: Reduction and fixation of the bone fragment attached to the medial head of the gastrocnemius muscle is important to restore tension of the gastrocnemius muscle, which serves as an important posterior joint stabilizer.