Multiple reference axes should be used to improve tibial component rotational alignment: a meta-analysis

Importance Use of the surgical transepicondylar axis (sTEA) is the gold standard when rotationally aligning components for total knee arthroplasty. Understanding how the tibial reference axes relate to the sTEA is essential if optimal tibial component rotational alignment is to be achieved. Aim To investigate the accuracy and reliability of all tibial anatomical landmarks relative to the sTEA. Evidence review A comprehensive literature search was performed in the PubMed/Medline database. A systematic review without limits was conducted and included all manuscripts reporting use of tibial reference axes as they relate to the sTEA. Reference lists from those manuscripts were subsequently searched for additional studies that met our inclusion criteria. For this systematic review, the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were used for analysis. Levels of evidence were assigned according to the Oxford Centre for Evidence-Based Medicine guidelines. A random-effects model was used to meta-analyse the data. Findings Of 2387 studies identified, 17 were included, and 9 tibial reference axes were used in the meta-analysis. Use of Akagi's axis was reported most frequently and measured 0.7 degrees of internal rotation to the sTEA. Conclusion and relevance Multiple reference axes should be used to optimise the rotational alignment of the tibial component. The combination of Akagi's axis, tibial posterior condylar axis and centre-to-medial 1/3 tibial tubercle axis will improve rotational accuracy. Level of evidence Level III.