A 76-year-old woman with obesity presented to the emergency department after being struck by a motor vehicle while walking to the store. She was awake and reported that her knee “bent the wrong way” as the vehicle hit her. Trauma evaluation revealed no intrathoracic or intraabdominal injuries. She had severe pain in the right knee but had preserved distal pulses and sensation. Anteroposterior radiographs showed lateral dislocation of the right knee (Panel A).
A feared complication of this injury is damage to the popliteal artery, which can result in ischemia and, in some cases, lead to amputation. Lateral dislocations can result in disruption of the anterior and posterior cruciate and medial collateral ligaments and are associated with peroneal nerve injury. After the patient received conscious sedation with ketamine, bedside knee reduction was performed (Panel B).
The patient had no neurovascular injury. She underwent external fixation of the knee and repair of the knee ligaments and was discharged to a skilled nursing facility on hospital day 9.