Instrumented static laxity evaluation. In Controversies in the technical aspects of ACL reconstruction: An evidence-based medicine approach. (Book Chapter)

Knee laxity is a highly complex issue, depending on an individual’s soft tissue quality and bony configuration. It can be evaluated both in a single and in multiple directions or statically and dynamically. Knee laxity is difficult to assess clinically, because it is highly dependent on the examiner’s experience, which in addition does not allow a precise quantification of knee laxity. Therefore, several devices have been developed to measure static knee laxity. In the early stages, they were limited to measurements in the sagittal plane. Over the last decade, static rotational laxity measurement devices have been added and are currently under development. Despite the fact that instrumented laxity assessments have been performed over several decades, limited knowledge is available on multidirectional static laxity assessments in large populations. Laxity evaluations in large groups followed over time could allow (1) for the study of physiological laxity and risk factors for knee injuries, (2) to confirm the diagnosis of soft tissue injuries, (3) to help distinguish between the different subtypes of anterior cruciate ligament (ACL) tears as well as associated injuries and (4) to follow patients who have had ACL reconstruction. This chapter will provide an overview of currently existing laxity devices and new findings on static knee laxity evaluations. Despite recent advances, there is still much work to be done to improve the use of arthrometers in the daily clinical practice.