Effect of Joint Line Elevation after Posterior-stabilized and Cruciate-retaining Total Knee Arthroplasty on Clinical Function and Kinematics

Abstract

Background:Joint line (JL) is a very important factor for total knee arthroplasty (TKA) to restore. The objective of this study was to evaluate the early clinical and kinematic results of TKAs with posterior-stabilized (PS) or cruciate retaining (CR) implants in which the JL was elevated postoperatively.Methods:Data were collected from patients who underwent TKA in our department between April 2011 and April 2014. The patients were divided into two groups based on the prosthesis they received (PS or CR). At 1-year postoperatively, clinical outcomes were evaluated by the American Knee Society (AKS) knee score, AKS function score, and patella score. In vivo kinematic analysis after TKA was performed on all patients and a previously validated three-dimensional to two-dimensional image registration technique was used to obtain the kinematic data. Anteroposterior (AP) translation of the medial and lateral femoral condyles, and axial rotation relative to the tibial plateau, were analyzed. The data were assessed using the Mann–Whitney test.Results:At time of follow-up, there were differences in the AKS knee scores (P = 0.005), AKS function scores (P = 0.025), patella scores (P = 0.015), and postoperative range of motions (P = 0.004) between the PS group and the CR group. In the PS group, the magnitude of AP translation for the medial and lateral condyle was 4.9 ± 3.0 mm and 12.8 ± 3.3 mm, respectively. Axial rotation of the tibial component relative to the femoral component was 12.9 ± 4.5°. In the CR group, the magnitude of AP translation for the medial and lateral condyle was 4.3 ± 3.5 mm and 7.9 ± 4.2 mm, respectively. The axial rotation was 6.7 ± 5.9°. There were statistically different between PS group and CR group in kinematics postoperatively.Conclusion:Our results demonstrate that postoperative JL elevation had more adverse effects on the clinical and kinematic outcomes of CR TKAs than PS TKAs.

The medial and lateral epicondyle as a reliable landmark for intra-operative joint line determination in revision knee arthroplasty

“… 3 , 4 , 9 Although subsequent studies reported the acceptable critical range as sd 5 mm, 8 , 11 more recently opinion in the literature on this subject has been changed by newer reports indicating that a deviation of more than 4 mm in the joint line proximally or distally from its normal position leads to unfavourable results. 10 - 13 , 14 - 16 Thus, it is clear that exact determination of the anatomical joint line is essential to achieve an optimal post-operative clinical outcome. We believe that the anatomical joint line can be restored within the acceptable zone of less than 5 mm proximally or distally from its neutral/original anatomical position by using this simple, and reproducible method that we have presented herein.…”

“…This issue still remains an object of interest. 9 - 11 The present study aimed to identify an accurate, reliable and easily performed standardised method for determining the correct anatomical position of the joint line intra-operatively during revision TKA. The hypothesis was that a ratio could be determined based on the distal and posterior articular distances from the epicondyles to indicate the imaginary borders of the distal femur and the level of the joint line in revision TKA, and therefore enable an accurate decision regarding the size and location of the femoral component.…”

Cruciate-Retaining Total Knee Arthroplasty

“…Since restoration of joint line can be difficult in severe osteoarthritic knee with coronal and sagittal plane deformities, many surgeons prefer the use of a PS TKR, which is less sensitive to changes in joint line position: in fact, the level of the reconstructed joint line is one of the main factors that affects the tension of the retained PCL [21]. As reported by Emodi et al in a cadaveric study "As the joint line was elevated, PCL strain increased at all measured flexion angles above 30°…" and "…the centre of tibio-femoral contact did not change at the flexion angles of 15 and 30°…" but "…at 60, 90 and 105° the tibio-femoral contact centre moved posteriorly with each successive elevation of the joint line."…”

Knieprothesendesign und Kinematik: Unterschiede in Radien, Konformität und Rotation/Pivot

“…Abgesehen von der Radiendiskussion bleibt festzustellen, dass nach unserem aktuellen Verständnis der wesentliche Schlüssel zur endoprothetischen Rekonstruktion der Kniegelenkkinematik und der Stabilität in mittlerer Beugung in der möglichst anatomischen Wiederherstellung der Gelenkflächen des Femurs liegt. Es ist evident, dass eine Anhebung der Gelenklinie beispielhaft zu einer Verkürzung des Hebelarms der Kniestreckung und zu einem Anstieg des retropatellaren Drucks führt [14,15] (▶ Abb. 2).…”