Pain and Patellofemoral Functionality in Total Knee Arthroplasty

A Comparative Cohort Study of Two Prosthesis Designs

Luis Miguel Cely, MD; Cesar Hernando Rocha, MD


Curr Orthop Pract. 2021;32(1):53-57. 

In This Article


The clinical results of the demographic variables included in the study were as follows. There were 132 knees (130 patients) operated from January 2015 to August 2019. Sixty-six surgeries were performed with Optetrak PS and 66 with Optetrak Logic. The average age of the patients was 67.4 yr, the ratio of women to men was 2.77 to 1. The average time of follow-up was 35 ± 8.59 (12 to 67) months. There were more right knees than left knees, without a significant difference. The preoperative alignment was varus in 76.5% of the patients. There were three patients with postoperative complications: two of them had grade 2 coronal instability that led to a revision with constrained condylar prosthesis, and the one had a deep vein thrombosis. There were no patients with patellar clunk (Table 1).

The global results of the functional test were: Oxford preoperative 16 (poor), Oxford postoperative 50 (excellent); KSS preoperative 32 (poor), KSS postoperative 85 (excellent); Kujala preoperative 28 (poor), Kujala postoperative 76 (good) (Table 2).

The results of the intragroup comparison for the Optetrak PS prosthesis showed no significant differences between the preoperative and postoperative periods for flexion average. However, for knee extension and functional tests, the P value was less than 0.05. There was significant improvement in Oxford, KSS, and Kujala scores, the last results showing good results compared with preoperative evaluations (Table 3).

Furthermore, the results of the intragroup comparison for the Optetrak Logic prosthesis regarding the average of preoperative and postoperative flexion did not show differences. However, the average of extension and the functional tests had differences (P < 0.05), demonstrating that there was improvement with the intervention carried out in all the scales that evaluated knee pain and functionality (Table 4).

When comparing Optetrak PS with Optetrak Logic, the average knee flexion in postoperative period showed significant differences with P=0.001, with a higher average flexion in the Optetrak PS group. There were no significant differences for the other parameters such as knee extension and instability (Table 5). Oxford and KSS scales showed significance (P>0.05) (Oxford: P=0.225; KSS: P=0.157); however, the score results were better with Optetrak Logic. Finally, the Kujala scale showed a P value=0.225, which was not statistically significant; however, for Optetrak Logic the postoperative results were better than for Optetrak PS (Table 6).