The variable functional disability of the anterior cruciate ligament-deficient knee.

The goal of the authors has been to define the syndrome of the anterior cruciate ligament-deficient knee. These concepts have been applied to pertinent articles in order to explain the discrepancies and contrasting opinions in the literature. The authors have suggested guidelines for treatment based on the quantification of risk factors and a method for the prediction of the functional disability level of patients. Functional disability is activity level-related and is also related to the type of sport and the intensity level of play. Functional disability is symptomatically expressed by pain, swelling, and giving way, which must be correlated with a specific activity level.