Article
Translational and rotational knee joint stability in bi-compartmental anterior and posterior cruciate-retaining knee arthroplasty
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Published: | October 21, 2010 |
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Objective: The anterior cruciate ligament (ACL) is sacrificed in the majority of total knee arthroplasty (TKA) surgeries, whereas TKA is currently performed either with preservation or with substitution of the posterior cruciate ligament (PCL). The rationale for retaining the PCL in the TKA design includes that it enhances stability, reproduces more physiological tibiofemoral kinematics, decreases shear force between implant-bone interface, and maintains the proprioception. Theoretically, similar advantages may be provided by the bicruciate-retaining bi-compartmental Knee Arthroplasty (BKA) design. Therefore, the objective of the current study was to investigate passive translational and rotational stability properties of the natural knee joint, with bicruciate-retaining BKA and with posterior cruciate retaining TKA. We hypothesized that, comparing to the native knee, the joint laxities in anterior-posterior translation, internal-external rotation, and valgus-varus rotation are not affected after (a) an bicruciate-retaining BKA or (b) an ACL- sacrificing (PCL-Retaining) TKA.
Methods: Fourteen human cadaveric knee specimens were used in this study as well as a robotic manipulator with six-axis force/torque sensor was used to test the joint laxity in anterior-posterior translation, valgus-varus, and internal-external rotation.
After the coordinate systems of the knee specimen had been determined, a so-called passive path was then generated and learned by the robotic manipulator which was then recorded in the robotic system to serve as a baseline knee flexion path. A 130 N of anterior and posterior tibial force, 5 Nm of internal, external, valgus, and varus tibial torques were applied on the same knee specimen, and the resulting laxity values were determined in the corresponding loading directions. All these laxity tests were performed at each 15 degree between 0 and 90 degree of knee flexion. These trials were performed on the intact knee joint, after bicruciate-retaining BKA and after posterior cruciate retaining TKA in the same specimen
Results and Conclusions: The results show that the knee joint stability after bicruciate-retaining BKA in anterior-posterior, internal-external, and valgus-varus directions is similar to that of the native knee. On the other hand, the PCL-retaining TKA results in inferior joint stability in valgus, varus, external rotation, anterior and posterior directions.
Our findings suggest that, provided functional ligamentous structures, bicruciate-retaining BKA is a biomechanically attractive and reasonable treatment for bicompartimental joint degenerative disease.