Patellofemoral complications after posterior-stabilized total knee arthroplasty: a comparison of 2 different implant designs.

Abstract

We conducted a retrospective review of 2 consecutive series of posterior-stabilized total knee arthroplasties (TKAs) to evaluate patellofemoral complications, in particular, significant patellofemoral crepitance or patellar clunk syndrome. Twenty posterior-stabilized Axiom PSK (Wright Medical Technology, Arlington, TN) TKAs (group 1) were compared with 20 posterior cruciate-sacrificed Advance medial pivot (Wright Medical Technology, Arlington, TN) TKAs (group 2). The average age in group 1 was 69 years and in group 2 was 70 years. Preoperative valgus alignment in group 1 was 7.5 degrees and in group 2 was 1.3 degrees. Postoperative valgus alignment for the 2 groups was 4.8 degrees and 5.3 degrees valgus. Postoperative patellar tilt for the 2 groups was 0.9 degrees lateral tilt and 8 degrees lateral tilt. Patellofemoral signs of crepitance > or =2+ and significant box impingement complaints of either snapping or clunking decreased significantly postoperatively from 5 of 20 (25%) in group 1 to 0 of 20 in group 2 (P=.0079).