Neutral mechanical alignment: Stickin' with the one that brung ya- Affirms

Restoring the overall mechanical alignment to neutral has been the gold standard in total knee arthroplasty since the 1970s. Recently, there has been renewed interest in alternative alignment goals that place implants in a more “physiologic” position with the hope of improving clinical outcomes. However, placing components outside of the classic “safe zone” of ± 3° is controversial, as studies have shown increased risk of mechanical failure, especially in obese patient populations. This paper will outline mechanical and kinematic alignment and present the evidence for why mechanical alignment is still the gold standard in total knee arthroplasty.