Initial evaluation of the acute multiple-ligament-injured knee

The multiple-ligament-injured knee is an orthopaedic emergency. The initial assessment of this injury must include a thorough and expedient physical examination, with particular attention directed to the vascularity of the extremity. Vascular injuries should be ruled out immediately because a pulseless extremity may result in a below-knee amputation if the leg is not reperfused within 6 to 8 hours. All patients with a normal vascular examination must have serial pulse examinations or undergo an arteriogram, because intimal tears may present on a delayed basis. The neurological examination, particularly of the peroneal nerve, should be documented. A detailed examination of the knee ligaments is performed on the anterior cruciate ligament, posterior cruciate ligament, medial collateral ligament, and posterolateral anatomic structures. Initial and postreduction radiographs require thorough evaluation to assess for peri-articular fractures, direction of dislocation, and adequacy of reduction. Magnetic resonance imaging will provide detailed information about the ligaments, bone or subchondral bone, menisci, and articular cartilage. The physical examination must be correlated with the magnetic resonance imaging findings for preoperative planning. This article provides a treatment algorithm that can be helpful in the initial assessment and decision-making process of the multiple-ligament-injured knee.