Avulsion of the femoral attachment of the medial collateral ligament in the setting of knee multiligament injury: A case report.

RATIONALE: Medial collateral ligament (MCL) injury is a common sports injury. The damage mainly occurs in ligament fibers, but MCL avulsion fracture is extremely rare and only a few reports have been published.

PATIENT CONCERNS: Herein, we present a healthy 21-year-old man with an avulsion fracture of the MCL of the right knee sustained during snowboarding.

DIAGNOSIS: Clinical and radiographic findings confirmed the presence of an avulsion fracture at the proximal attachment of the MCL, combined with complete anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) rupture.

INTERVENTIONS: The patient underwent single-stage ACL, PCL reconstruction, and MCL repair.

OUTCOMES: Two weeks after the surgery, the patient developed heterotopic ossification (HO) at the medial side of the knee, HO tended to be stable and mature at the 3-month follow-up examination. One year after the operation, the patient's knee was fully functional, stable, and pain free.

LESSONS: Femoral attachment avulsion fracture of the MCL is in contrast to common isolated MCL injuries. Early surgical repair is advocated for the greatest benefit. Orthopedic surgeons should keep the potential complication HO in mind and develop rational strategies for HO prevention and treatment.