Bicruciate Stabilized Total Knee Arthroplasty shows higher Femoral Rollback compared to an analogue Cruciate Retaining System during loaded and unloaded activities

Objectives The apparent greater physiological kinematics of bicruciate total knee arthroplasty (BCS) systems have been attributed to the anterior and posterior post-cam mechanism system [1]. Although previous comparisons with different cruciate ligament strategies have been conducted [2], [3], the analysis of two implants with identical bearing geometry but different cruciate ligament strategies under equal loading conditions is missing. Knowledge about the kinematic effect would be valuable to facilitate any pre-operative planning and decision-making on selecting the most appropriate device for a patient.

Methods In a retrospective study, 10 subjects with a BCS-TKA system (n = 10; 63.8+/-6.6 years (mean+/-SD), 6 males, 4 females, 30.3+/-2.0 BMI; Journey II Bi-Cruciate Stabilized, Smith & Nephew, Inc.) and 10 with a CR-TKA system (n = 10; 69.1+/-6.0 years, 6 males, 4 females, 31.5+/-2.6 BMI; Journey II Cruciate Retaining, Smith & Nephew, Inc.) were recruited. Fluoroscopic analysis during unloaded flexion-extension and loaded lunge was conducted at 24 months after index surgery. Medial and lateralm condyle points were generated to achieve a quantification of tibio-femoral kinematics [4]. All patients answered the KSS, FJS and HFKS questionnaires.

Results and Conclusion The BCS cohort showed in both activities a higher femoral lateral rollback as well as a medial pivot. In contrast, the CR cohort showed a significant increase in anterior translation on the medial compartment as well as an almost absent femoral lateral rollback. Higher clinical values were also observed in the BCS cohort and seem to be correlated with reduced anterior translation as well as higher femoral lateral rollback.

Absolute mean tibiofemoral kinematics during unloaded (Flexion-Extension) and loaded (Lunge) activities. The marked points indicate the position during knee extension

At 24 months post-surgery, the results of this study showed expected knee joint kinematics in the BCS cohort, which were however influenced by the interaction between the bearing surfaces, the dual post-cam mechanism and the loading conditions. The kinematics in this group could eventually profit by a smooth transition between the interchanging surfaces. Regarding the CR group, the equal bearing geometry alone seem to be insufficient in reducing anterior shift, which could not be stopped by the apparent insufficient post-operative tension in the PCL. Careful selection of patients to be implanted with a CR design is recommended.

Stichwörter Total knee arthroplasty, cruciate retaining, bi-cruciate substituting, fluoroscopy

• 1 Grieco TF. et al. J Arthroplasty. 2018
• 2 Kono K. et al. Knee Surg Sports Traumatol Arthrosc. 2019
• 3 Iriuchishima T. et al. Indian journal of orthopaedics. 2019
• 4 Pfitzner T. et al. Knee Surg Sports Traumatol Arthrosc. 2017

Publication History

Article published online:
15 October 2020