Parham Salehi Saee, MS3; Nathan C Ellis, MD; Dhimitri A Nikolla, DO; Melody ‎Milliron, DO

1Lake Erie College of Osteopathic Medicine, Erie, PA.‎
‎2Department of Emergency Medicine, Saint Vincent Hospital, Allegheny Health Network, Erie, ‎PA. ‎

Corresponding Author:‎
Dhimitri A. Nikolla, DO
Department of Emergency Medicine
Saint Vincent Hospital ‎
Allegheny Health Network
‎232 West 25th Street
Erie, PA, 16544‎
Twitter Handle: @DhimitriNikolla‎


A 23-year-old male presented to the emergency department (ED) with acute pain and deformity ‎of the left knee after falling off his skateboard. Examination revealed the knee bent 90 degrees ‎with posterior displacement of the proximal tibia. Motor, sensory, and pulses intact in the left ‎foot. Lateral radiograph revealed a posterior dislocation of left knee (image). Closed reduction ‎and splinting were performed in the ED with procedural sedation. Computed tomography ‎angiography (CTA) revealed no evidence of acute popliteal arterial vascular injury. The patient ‎was admitted and magnetic resonance imaging revealed ligamentous injuries to the anterior, ‎posterior, and medial collateral ligaments (ACL, PCL, MCL). He underwent open repair of the ‎MCL the next day with plans for delayed treatment of the ACL and PCL injuries after physical ‎therapy to improve strength and knee range of motion.‎

Posterior knee dislocations are high energy injuries usually caused by a direct impact on the ‎proximal tibia resulting in posterior dislocation with respect to the distal femur.1 They usually ‎present with severe pain, swelling, instability and limited range of motion of the knee. ‎Spontaneous reduction prior to ED arrival may allow the dislocation to go unrecognized despite ‎imaging and result in delayed diagnosis.2 Up to 32% of knee dislocations are complicated by ‎vascular injury; most commonly popliteal artery injury.3, 4 Nevertheless, selective CTA based ‎on history and physical examination is more commonly recommended than routine ‎angiography.4, 5‎