The pivot-shift phenomenon during computer-assisted anterior cruciate ligament reconstruction

Anterior cruciate ligament reconstruction was one of the first procedures in which computer-assisted techniques were used in orthopaedic surgery. However, the use of navigation for tunnel placement in anterior cruciate ligament surgery remains problematic, as the optimal position for placement of the tunnels is debatable. The technical specification of tunnel position is clinically relevant, but the targets and tolerances for this technical specification are poorly understood. The inability to reliably quantify knee kinematics and stability before, during, or after anterior cruciate ligament reconstruction remains a problem. A navigated examination to assess knee stability could potentially close the computer-assisted surgery treatment loop by providing quantitative feedback about various reconstruction techniques. Recent iterations of navigated examinations for the assessment of stability include even complex pathologic movements, such as those detected with the pivot-shift examination. In this paper, we review conventional stability measurements of the knee and compare them with navigated techniques, with a focus on the navigated pivot-shift examination. In summary, direct intraoperative measurements and quantifications of knee stability, including the pivot-shift phenomenon, are now possible with the use of navigation. Consequently, more reproducible and clinically meaningful quantification of the pivot-shift phenomenon may allow for more accurate evaluation of various anterior cruciate ligament reconstruction techniques in the future.