In Vivo Knee Kinematics: How Important Are the Roles of Femoral Geometry and the Cruciate Ligaments?

Abstract

Background: While posterior cruciate-retaining (PCR) implants are a more common total knee arthroplasty (TKA) design, newer bicruciate-retaining (BCR) TKAs are now being considered as an option for many patients, especially those that are younger. While PCR TKAs remove the ACL, the BCR TKA designs keep both cruciate ligaments intact, as it is believed that the resection of the ACL greatly affects the overall kinematic patterns of TKA designs. The objectives of this study are to assess the in vivo kinematics for subjects implanted with either a PCR or BCR TKA and to compare the in vivo kinematic patterns to the normal knee during flexion. These objectives were achieved with an emphasis on understanding the roles of the cruciate ligaments, as well as the role of changes in femoral geometry of nonimplanted anatomical femurs vs implanted subjects having a metal femoral component. Methods: Tibiofemoral kinematics of 50 subjects having a PCR (40 subjects) or BCR (10 subjects) TKA were analyzed using fluoroscopy while performing a deep knee bend activity. The kinematics were compared to previously published normal knee data (10 subjects). Kinematics were determined during specific intervals of flexion where the ACL or PCL was most dominant. Results: In early flexion, subjects having a BCR TKA experienced more normal-like kinematic patterns, possibly attributed to the ACL. In mid-flexion, both TKA groups exhibited variable kinematic patterns, which could be due to the transitional cruciate ligament function period. In deeper flexion, both TKA functioned more similar to the normal knee, leading to the assumption that the PCL was properly balanced and functioning in the TKA groups. Interestingly, during late flexion (after 90 ), the kinematic patterns for all three groups appeared to be statistically similar. Conclusion: Subjects having a PCR TKA experienced greater weight-bearing flexion than the BCR TKA group. Subjects having a BCR TKA exhibited a more normal-like kinematic pattern in early and late flexion. The normal knee subjects achieved greater lateral condyle rollback and axial rotation compared to the TKA groups.

Native knee kinematics is not reproduced after sensor guided cruciates substituting total knee arthroplasty

“…Multiple authors have shown that the motion of the normal knee joint depends on the interaction between the shape of the articular surfaces and the ligaments crossing the knee joint [ 3 , 39 ]. In the normal knee, the femoral condyles undergo a combination of rolling, sliding, and rotation on the tibial plateau during flexion.…”

Cruciate ligament force of knees following mobile-bearing unicompartmental knee arthroplasty is larger than the preoperative value

“…In TKA, sacrificing the ACL reportedly achieved inferior clinical outcomes 21 . Moreover, compared to posterior cruciate-retaining (PCR)-TKA, BCR-TKA achieved more normal-like kinematics 22 . Finally, it has been reported that normal-like kinematics promote favorable clinical outcomes 23 .…”

Comparison of the Journey II bicruciate stabilised (JII-BCS) and GENESIS II total knee arthroplasty for functional ability and motor impairment: the CAPAbility, blinded, randomised controlled trial

“…None of the other papers reporting outcomes of the JII-BCS compared the JII-BCS to the Genesis II, none used a randomised design and none used methodology or outcomes that could be compared with the methodology used in this trial. [42][43][44][45][46] However, on the basis of the available literature, we measured outcomes that would be expected to be difference on the basis of the available literature, walking velocity, step-length symmetry (resulting from longer stride length), knee ROM and peak knee angular velocity. Within our trial, we found differences in some biomechanical measures of motor impairment but not for others; patient-reported outcomes; and, walking and balance function.…”