Diagnosis and treatment of posterolateral knee injuries.

Posterolateral knee injuries can be very debilitating. It is important to understand the complex anatomy and pertinent diagnostic tests to properly treat posterolateral knee injuries. The fibular collateral ligament, popliteus tendon, and the popliteofibular ligament are the main static stabilizers against abnormal varus and posterolateral translational moments. Important radiographic imaging studies for the posterolateral knee include full length anteroposterior radiographs, taken with the patient standing, to assess for varus alignment in patients with chronic injuries and high field (1.5 tesla or higher) magnetic resonance imaging with specific posterolateral knee sectioning. A physical examination that includes the external rotation recurvation test, varus stress test at 30 degrees, dial test at 30 degrees and 90 degrees, posterolateral drawer test, reverse pivot shift, and an assessment for a varus thrust gait are essential to properly diagnose a posterolateral knee injury. Patients with acute (< 3 weeks) anatomic repairs of Grade III posterolateral knee injuries have the best functional outcome. Although various surgical reconstruction techniques have been developed to treat chronic or irreparable acute posterolateral knee injuries, these techniques have not achieved outcomes comparable with the treatment of other ligament injuries of the knee. Techniques for anatomic reconstructions of these structures are just being developed. Improved education of clinicians as to the proper diagnosis of posterolateral knee injuries is necessary because a large number of these injuries still are missed on initial examinations. In addition, additional research into the most optimal posterolateral knee reconstruction techniques and outcome studies are needed to improve the treatment of this debilitating knee injury.