Pain and patellofemoral functionality in total knee arthroplasty: a comparative cohort study of two prosthesis designs

Abstract

Background: Total knee arthroplasty designs have changed from the original design, with the goal of becoming as close to normal knee biomechanics and anatomy as possible. Since 2009, Optetrak® Logic incorporated modifications to the previous product Optetrak® PS (Exactech, Gainsville, FL), with a change of the anterior surface of the tibial post of the polyethylene insert and the surface that articulates with the femoral component box. Also, the sagittal geometry of the femoral trochlea was changed, which decreased rates of anterior knee pain and “patellar clunk.” The purpose of this study was to determine if there are differences in terms of pain and patellofemoral functionality between Optetrak PS and Optetrak Logic. Methods: A prospective follow-up was performed comparing the results of the Kujala pain and patellofemoral functionality scale. Clinical and functional follow-up was performed in 132 knees (66 from the Optetrak Logic group and 66 from the Optetrak PS group) that underwent total knee arthroplasty from January 2015 to August 2019. Results: Global results of the functional tests were: Oxford postoperative 50; Knee Society Score postoperative 85; Kujala postoperative 76. In comparing the two groups the Kujala score for Optetrak PS was 71 and the Kujala score for Optetrak Logic was 81. Conclusions: Patellofemoral knee pain and functionality before and after total knee arthroplasty must be analyzed with functional scales. The new prosthetic designs are gentler to the patellofemoral joint, and this has been verified by objective analysis with functional scales such as the Kujala scale. Level of Evidence: Level III.