Posterior-stabilized and ultracongruent designs are 2 common examples of posterior cruciate ligament-substituting total knee arthroplasty (TKA) prostheses. There is a lack of evidence regarding joint perception differences between ultracongruent and posterior-stabilized TKA. The purpose of this study was to compare the postoperative knee stability, function, and joint perception between ultracongruent and posterior-stabilized TKA in the same patients in order to determine whether there was a difference based on design.
This prospective, randomized controlled trial included 50 patients who underwent same-day bilateral TKA utilizing Persona (Zimmer Biomet) posterior-stabilized implants in 1 knee (posterior-stabilized group) and ultracongruent implants in the other knee (ultracongruent group). At 2 years postoperatively, patients were evaluated for knee stability, function, and joint perception. Postoperative static knee anteroposterior stability and femoral rollback were compared. Knee function was evaluated with use of the Knee Society Score and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Joint perception was compared by evaluating noise generation, side preference, satisfaction, and the Forgotten Joint Score.
The ultracongruent group had more knee anteroposterior laxity (4.5 mm compared with 1.8 mm in the posterior-stabilized group; p < 0.001) and less femoral rollback (4.2 mm compared with 9.0 mm in the posterior-stabilized group; p < 0.001). Knee Society Score and WOMAC scores were not significantly different between groups (all p > 0.05). Although the ultracongruent group showed less noise generation than the posterior-stabilized group (18% compared with 38%, respectively; p = 0.026), there were no differences in side preference, satisfaction, or Forgotten Joint Score (all p > 0.05).
Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.
Both groups had similar joint perception 2 years postoperatively, with obvious differences in noise generation and more sagittal laxity with less femoral rollback in the ultracongruent group.