Kinematic and Mechanical Alignment Yield Similar Outcomes in Total Knee Arthroplasty: A Systematic Review and a Meta-Analysis of Randomized Controlled Trials.
Benjamin W Blackman, Carly A Burow, Matthew P Macciacchera et al.
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In 30 seconds
This systematic review and meta-analysis of 11 randomized controlled trials compared kinematic alignment (KA) with mechanical alignment (MA) in total knee arthroplasty, including 972 patients and a mean follow-up of 3.9 years. Overall, the strategies showed no statistically significant differences in all-cause reoperation or patient-reported outcome measures. In bilateral TKA studies, patients were more likely to prefer the KA knee (relative risk 2.15, 95% CI: 1.36 to 3.40). The authors conclude that objective outcomes and patient-reported measures are similar, while longer-term evidence is needed.
Key findings
- All-cause reoperation did not differ significantly between KA and MA (RR: 1.34, 95% CI: 0.71 to 2.52, P = 0.37).
- Patient-reported outcome measures showed no statistically significant difference between alignment strategies.
- In bilateral TKA studies, patients were more likely to prefer the KA knee (RR: 2.15, 95% CI: 1.36 to 3.40).
- Beyond 10 years, two studies found no significant difference in all-cause reoperations or component revisions.
Why it matters
The findings suggest that KA and MA produce broadly similar measured outcomes in the randomized evidence, while patient preference in bilateral comparisons may favor KA. This distinction is relevant when interpreting alignment strategies: preference does not establish superior survivorship or patient-reported outcomes. The review also highlights the need for longer follow-up and evidence identifying which patients, if any, benefit most from KA.
What to keep in mind
Mean follow-up was 3.9 years, and evidence beyond 10 years came from only two studies; longer-term comparisons remain limited.