Comparative Effectiveness of Contemporary Alignment Strategies in Total Knee Arthroplasty: A Systematic Review and Network Meta-Analysis.

Authors

Guan Hao Chester Tan, Hui-Shan Angela Lim, Leah Robin Thorpe, Charles Kon Kam King, Ing How Moo

Published in

The Journal of arthroplasty. Nov 06, 2026. Epub Nov 06, 2026.

Abstract

Patient-specific alignment strategies are increasingly used in total knee arthroplasty (TKA), but comparative clinical benefit over mechanical alignment (MA) remains uncertain. We compared contemporary alignment strategies using the Forgotten Joint Score (FJS) as the primary outcome.
There were four bibliographic databases searched from January 2000 to February 2026 for randomized controlled trials (RCTs) and comparative observational studies of primary TKA. Eligible studies compared unrestricted kinematic alignment (uKA), restricted kinematic alignment (rKA), functional alignment (FA), adjusted MA, or inverse restricted kinematic alignment with MA or another strategy. Random-effects pairwise meta-analysis and frequentist network meta-analysis (NMA) were performed to synthesize sparse direct and indirect comparisons across connected alignment strategies. Secondary outcomes were Oxford Knee Score (OKS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and range of motion (ROM)/flexion. Certainty was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) framework. There were 61 studies (22 RCTs, 39 observational; 7,822 patients) that were included.
Compared with MA, FJS improved with FA (mean difference [MD] 14.24, 95% confidence interval [CI] 3.32 to 25.16), uKA (MD 12.28, 95% CI 9.06 to 15.51), and rKA (MD 8.75, 95% CI 3.41 to 14.08). Only FA exceeded the lower FJS minimal clinically important difference threshold, but heterogeneity was high. Study-design stratification reduced several favorable estimates, including the FJS advantage of uKA over MA, which was larger in observational studies than in RCTs (MD 13.76 versus 7.49). The secondary OKS, WOMAC, and ROM/flexion effects were smaller and generally below accepted clinical thresholds. In NMA, FA and uKA ranked highest for FJS in all-study analyses, whereas RCT-only rankings were less decisive. The GRADE certainty was Low for rKA versus MA FJS and Very Low for other Tier 1 comparisons.
Contemporary non-mechanical alignment strategies statistically improve FJS after TKA, but clinically meaningful and certain superiority over MA is not established. Longer, adequately powered RCTs are needed before one strategy can be preferred.

PMID:
42994644
Bibliographic data and abstract were imported from PubMed on 07 Nov 2026.

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