Biomechanics and physical examination of the posteromedial and posterolateral knee: state of the art

The posteromedial and posterolateral corner structures contribute significantly to knee stability. The posterior oblique ligament is a primary restraint to internal rotation and a secondary restraint to valgus. The superficial fibres of the medial collateral ligament are the primary valgus restraint and also provide secondary internal and external rotation stability. The deep fibres of the medial collateral provide additional restraint to internal and external rotation as well as valgus. The posteromedial capsule provides a secondary restraint to valgus and posterior translation. The lateral (fibular) collateral ligament is the primary varus stabiliser. The popliteus tendon complex is a primary restraint to external rotation. The popliteofibular ligament is a secondary restraint to external rotation and varus. Many physical examination manoeuvres have been described to assess these structures. Manoeuvres assessing the posterolateral structures include the varus stress test, dial test, the posterolateral drawer, the external rotation recurvatum test, heel height test and the reverse pivot shift. Examination manoeuvres that assess the posteromedial structures include the valgus stress test, dial test, anterolateral drawer test and anteromedial drawer test. Proper application of physical examination manoeuvres in conjunction with other diagnostic modalities will allow providers to develop appropriate treatment plans.