A case of anterior cruciate ligament tear accompanied by avulsion fractures of tibial tuberosity and Gerdy's tubercle

A 54-year-old man visited our clinic due to a painful swelling of his right knee. He had attempted a forceful kick by his right leg during a Sepak Takraw-like sports activity, only to fail to hit the ball. He felt a popping sense on the knee and collapsed, even without direct trauma. Imaging studies revealed a disruption of the anterior cruciate ligament (ACL), and separate avulsion fractures of the tibial tuberosity and Gerdy's tubercle. The fractures were stabilized by two cancellous screws, respectively. The intra-operative fluoroscopy demonstrated a manifest ACL insufficiency. A simultaneous reconstruction of the ligament was not performed. At 6 months after surgery, he had no difficulty in his activities of daily living. The involved knee joint was believed to have undergone a forceful pivot shift mechanism. Injuries to the ACL can be suspected from indirect signs on the radiologic images by a careful reconstitution of the injury mechanism and the associated lesions. Manifest osseous lesions on the plain radiographs can herald a major ligamentous injury and may be interpreted as an indirect sign of the ACL injury, which helps to establish a relevant management plan.