Navigation for anterior cruciate ligament surgery

Abstract

Anterior cruciate ligament (ACL) reconstruction is a common and generally successful surgical procedure. Recent studies, however, have demonstrated a failure of traditional techniques to restore knee kinematics. Surgical navigation allows for an augmented three dimensional view of the surgical field and can provide quantitative feedback to supervise surgical decision-making. In addition, knee kinematics can be accurately tracked using these systems. These computer-assisted surgery systems have been proposed for refinement of tunnel positioning in ACL surgery. Navigation systems, however, are best used when clearly defined targets have been established. To date, controversy remains concerning optimal positioning of ACL tunnels; as such, it remains unclear which targets should be used for navigation. Navigation systems have become an increasingly popular tool to track intraoperative knee kinematics. Studies have demonstrated that the systems are accurate in quantifying uniplanar examinations such as the Lachman and arcs of rotation at a defined flexion angle, as well as complex multiplanar examinations such as the pivot shift. The repeatability of standardized load application, however, limits the generalizability of quantitative data. Never-the-less, these tools have proven valuable in the basic science arena and have been used to assess the time zero performance of various ACL reconstruction constructs. In the future, standardized mechanical testing devices and non-invasive tracking strategies may allow for longitudinal use of navigation systems for outcome analysis. In addition, if targets can be identified for optimal tunnel positions, navigation may become valuable in refining surgical techniques.