OBJECTIVE: This study aimed to evaluate whether the posterior cruciate ligament sacrifice during total knee arthroplasty (TKA) has any effect on postoperative standing balance or not.
METHODS: The patients who underwent bilateral TKA with either CR or PS design were analyzed. 30 patients (10 PS, 20 CR) were included for the final analysis. TKA designs were compared in terms of Lysholm score, range of motion, and balance characteristics including somatosensorial, vestibular, and visual balance scales, adaptation, limits of stability, and weight-bearing/squat tests by computerized dynamic posturography.
RESULTS: The mean follow-up time was 59 months for CR, 49 months for PS group. The average Lysholm score values were 94 for CR and 95 for PS group, indicating functionally similar patient groups. The average knee flexion was found significantly higher in PS group (114°) compared to CR group (102°) (p = 0.009). In the CR group, motor adaptation tests (toes up/toes down) were found to be better (p = 0.034). In the on-axis velocity parameter (linear goal orientation) of limits of stability test, PS group patients were found to be more successful (p = 0.035).
CONCLUSIONS: The use of CR implants can be recommended in patients with a high risk of falling since they provide better motor adaptation providing rapid reactions to rapid surface changes. Better linear goal orientation in PS group, providing a faster movement in an intended direction, should be considered when planning the ideal implant for the patients with relevant activities.

Posterior stabilized (PS) polyethylene inserts have been shown to have excellent long-term functional results following total knee arthroplasty (TKA). A cruciate-substituting (CS) design has been introduced to minimize bony resection and eliminate concerns regarding wear on the PS post. The purpose of this study is to compare the outcomes of patients who underwent TKA using either a PS or CS insert.
We reviewed a consecutive series of 5970 patients who underwent a cruciate-sacrificing TKA and received either a PS (3,314) or CS (2,656) polyethylene liner. We compared demographics, Knee Injury and Osteoarthritis Outcome Score Jr (KOOS Jr), Short-Form 12 (SF-12) scores, and revision rates between the groups at a minimum 2 years followup. A multivariate regression was performed to identify the independent effect of design on functional outcomes.
Revision rates between the groups were comparably low (0.35% for PS vs 0.51% for CS, P = .466) at an overall mean follow-up of 43 months. Patients in the PS cohort had statistically higher KOOS Jr scores at 2 years (69.8 vs 72.9, P < .001). Multivariate regression analysis found CS patients to have lower postoperative KOOS Jr scores (estimate -2.26, P = .003), and less overall improvement in KOOS Jr scores (estimate -2.42, P = .024) than PS patients, but neither was a clinically significant difference.
Patients who undergo TKA with a CS polyethylene insert have comparable functional outcomes and revision rates to those with a PS design at short-term follow-up. Longer follow-up is needed to determine whether CS can match the outstanding track record of PS TKA.