Knee and Lower Leg

More than 1 million knee injuries are treated annually in North American emergency departments (EDs). These injuries range in severity from minor contusions to limb-threatening injuries to the popliteal artery. The knee joins the longest mechanical levers in the body, the femur and tibia, and is therefore subject to high forces. It is the largest and most complex joint in the body and functions through a complicated interaction of flexion, extension, rotation, gliding, and rolling. Its large synovial space frequently is involved in infections and other inflammatory conditions. The main goal in emergency evaluation of the traumatized knee is to prevent further damage by identifying reparable vascular injuries, reducing dislocations, stabilizing fractures, and administering antibiotics when indicated. Definitive treatment of less urgent problems is deferred to other settings, such as primary care offices for chronic knee pain and orthopedic clinics for ligamentous injuries.