The medial collateral ligament (MCL) is the most commonly injured ligament of the knee; however, to our knowledge, avulsion fractures of the MCL resulting in an intra-articular fragment have not been reported. We present the case of a 55-year-old woman with a posterior cruciate ligament avulsion fracture and an MCL avulsion fracture with an intra-articular bony fragment.Conclusion:
Patients who sustain trauma to the knee should be carefully evaluated for ligamentous avulsion injuries. Avulsion fractures in adults represent substantial traumatic injuries, and associated injuries should be suspected. While the MCL is an extracapsular structure, this case report demonstrates that the MCL femoral-sided osseous attachment can displace intra-articularly.