KSSTA - 2026-04-22 - Journal Article
Better functional scores at 5 years following TKA with unrestricted kinematic alignment using medial-pivot versus ultracongruent implants.
Marchetti E, Bulle L, Combes A, ReSurg, Laurendon L, Badet R
Topics
Key Takeaway
At 5 years, kinematically aligned medial-pivot TKA (CR-MP and CS-MP) produced significantly better Kujala scores than ultracongruent designs (80.1/82.1 vs. 73.3, p<0.01), with CS-MP also yielding superior FJS (88.9 vs. 74.9, p=0.024).
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Summary
This retrospective study compared PROMs at 5 years in 137 kinematically aligned TKAs using three implant designs: ultracongruent, cruciate-sacrificing medial pivot, and cruciate-retaining medial pivot. Both MP designs produced significantly higher Kujala scores than UC on unadjusted and multivariable analysis (β=-6.27 for UC, p=0.011). CS-MP achieved superior FJS over UC on unadjusted analysis (88.9 vs. 74.9), though this did not survive multivariable adjustment; no significant difference was detected between CR-MP and CS-MP on any outcome.
Key Limitation
Non-randomized implant allocation means surgeon preference and patient anatomy likely influenced implant selection, and residual confounding cannot be excluded despite multivariable adjustment.
Original Abstract
PURPOSE
The purpose was to compare patient-reported outcome measures (PROMs) at 5 years following total knee arthroplasty (TKA) using unrestricted kinematic alignment with ultracongruent (UC) versus cruciate-sacrificing medial pivot (CS-MP) and versus cruciate-retaining medial pivot (CR-MP) designs.
METHODS
This was a retrospective analysis of a consecutive cohort of 140 TKAs with UC (n = 44), CS-MP (n = 44) and CR-MP (n = 52). Of the initial cohort, three died, leaving a final cohort of 137 (UC, n = 43; CS-MP, n = 44; CR-MP, n = 50). Patients completed pre- and post-operative questionnaires of the Knee Society Score (KSS 2011) Symptoms, Satisfaction, Expectations and Function components, the Kujala score and the Forgotten Joint Score (FJS). Multivariable analyses were performed to assess the association of implant type (CR-MP, CS-MP and UC) with postoperative Kujala score and FJS, adjusting for patient characteristics (age, body mass index [BMI], sex, preoperative phenotype, expectations and Wiberg classification).
RESULTS
Postoperative Kujala scores were significantly better for CR-MP and CS-MP (80.1 ± 9.8 and 82.1 ± 9.8) compared to UC (73.3 ± 14.4; p = 0.007 and p < 0.001). After adjusting for patient factors, multivariable analysis revealed a statistically significant negative association between postoperative Kujala scores and UC (β = -6.270; p = 0.011). Postoperative FJS was significantly better for CS-MP compared to UC (88.9 ± 11.5 vs. 74.9 ± 23.4; p = 0.024). After adjusting for age and sex, multivariable analysis did not reveal a statistically significant association between postoperative FJS and UC (β = -6.58; p = n.s.).
CONCLUSION
At 5-year follow-up, TKA using unrestricted kinematic alignment with MP designs achieved superior functional outcomes compared to UC designs, but no significant difference between CS-MP and CR-MP designs.
LEVEL OF EVIDENCE
Level III.