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Abstract Presented at the 26th Annual Meeting of the Arthroscopy Association of North America| Volume 23, ISSUE 6, SUPPLEMENT , e7, June 2007

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Computer-Assisted Evaluation of the Kinematics of the AM and PL Bundle and the Value of Parameters According to the IKDC Knee Ligament Examination Form (SS-12)

      Summary

      The aim of this cadaveric study was to describe the kinematics in the ACL-Intact (ACL-I), PL bundle-Deficient (PL-D), and ACL-Deficient (ACL-D) knee by applying a protocol for computer-assisted evaluation of knee kinematics. Our study demonstrated a force distribution between the two bundles that changes with knee position. Current clinical knee laxity measurements may not be suited for detecting subtle changes (like PL deficiency) in the ACL anatomy, and therefore might fail to assess outcome differences in various ACL reconstruction techniques.

      Purpose

      The double bundle concept is an accepted model for describing both the anatomy and the tension patterns of the AM and PL bundles in the ACL. The aim of this cadaveric study was to describe the kinematics in the ACL-Intact (ACL-I), PL bundle-Deficient (PL-D), and ACL-Deficient (ACL-D) knee by applying a protocol for computer-assisted evaluation of knee kinematics.

      Methods

      An optical position measurement system was used to acquire knee joint motion (n=10) during clinical evaluations by tracking markers rigidly attached to the bones. The protocol included acquisition of AP translations and IE rotations, and evaluation of the IKDC knee ligament examination form.

      Results

      Comparison of the AP translation between PL-D and ACL-D states demonstrated an increase at 0°, 15° and 30°. Comparison of IE laxities did not show any significant change between ACL-I, PL-D and ACL-D. The instrumented and the manual Lachman test, the total AP translation at 25° and 70°, and the pivot shift test showed differences between the PL-D and ACL-D states.

      Conclusions

      Our study demonstrated a force distribution between the two bundles that changes with knee position. Current clinical knee laxity measurements may not be suited for detecting subtle changes (like PL deficiency) in the ACL anatomy, and therefore might fail to assess outcome differences in various ACL reconstruction techniques. An instrumented measurement of rotational laxity needs to be evaluated as a step towards a more precise kinematic test of knee stability not only in the native and torn ACL but also in the reconstructed knee.