Editorial Commentary: The Measurement of Knee Laxity: Instrumented Measurement and Stress Radiography for Anterior Cruciate Ligament Injuries.

The measurement of anterior knee laxity in anterior cruciate ligament injuries is an established method for both clinical practice and clinical studies in regard to anterior cruciate ligament surgery. Stress radiography was succeeded or paralleled by instrumented testing with the development of standardized devices starting in the 1980s. Because knee stability depends on the flexion angle test, conditions need to be comparable for both instrumented testing and stress radiography. The lack of a general consensus becomes even more evident for testing and measuring rotational instability. Knee laxity measurement in all dimensions, such as with robots in cadaver studies, has not found its general application in the clinical setting yet, but will be expected in the near future.