In Vivo Assessment of the Kinematics in Normal and Anterior Cruciate Ligament-Deficient Knees

Abstract

The in vivo measurement of dynamic knee kinematics is important for understanding the effects of joint injuries and diseases and for evaluating the outcome of surgical procedures. Researchers have used in vitro approaches (involving cadavers), noninvasive approaches (involving studies done at gait laboratories), and in vivo approaches (involving roentgen stereophotogrammetry and fluoroscopy) to assess human knee motion. To ensure that the loads that are encountered during typical movements are accurately incorporated, treatments that are aimed at improving knee function should be evaluated with use of data that are obtained with dynamic measurement methods. This requires that the six-degrees-of-freedom pose (position and orientation) of objects be measured during dynamic activities. The purpose of the current study was to accurately determine the three-dimensional kinematic patterns of normal and anterior cruciate ligament-deficient knees during in vivo weight-bearing activities with use of a novel intensity-based two-dimensional to three-dimensional image registration method, similar to that previously utilized to analyze the kinematics of total knee arthroplasty1. ### Model Creation Ten healthy normal volunteers with an average age of thirty-seven years (range, twenty-two to forty-four years) and an average body mass of 76 kg participated in the study. These volunteers exhibited no lower extremity abnormalities on T2-weighted fast-spin-echo magnetic resonance imaging and had no clinically measurable knee ligament instability on either the pivot-shift test or the Lachman test. In addition, five patients with a recent isolated anterior cruciate ligament tear (that is, a tear that had occurred within the previous four to six weeks), who had an average age of thirty-nine years (range, twenty-five to forty-seven years) and an average body mass of 65 kg, were also included in the study so that the kinematics of anterior cruciate ligament-deficient knees could be compared with those of normal knees. The five patients with an anterior cruciate ligament-deficient knee were …