The Effect of Tibial and Femoral Component Coronal Alignment on Survivorship After Total Knee Arthroplasty: A Systematic Scoping Review of the Literature.

Background: Component alignment in contemporary total knee arthroplasty (TKA) is frequently achieved through personalized alignment philosophies that aim to restore prearthritic knee anatomy. The long-term clinical efficacy and safety of these approaches remain uncertain. This comprehensive review assessed the relationship between coronal component alignment and TKA implant survivorship. Methods: A scoping review was performed of published primary TKA studies that (1) reported postoperative tibial or femoral component coronal alignment on long-leg radiography, (2) reported survivorship with a minimum 12-month follow-up, and (3) were written in English. The review adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and its scoping review extension (PRISMA-ScR). The primary Results: Of 3,786 screened studies, 332 underwent full-text review and 51 met inclusion criteria, encompassing 7,944 patients (9,687 TKAs) (mean [SD] age 68.1 [3.2] years; mean [SD] follow-up 4.6 [3.3] years). Most studies (76.5%, n = 39/51) investigated a single alignment philosophy (most commonly mechanical alignment [MA], n = 23, 56.1% of single-philosophy studies), while 10/51 (19.6%) compared 2 philosophies. Only 5 studies (9.8%) included >500 TKAs. Long-term follow-up (>10 years) was reported in 9 MA studies (28.1% of MA reports), 5 of which noted decreased survivorship with component varus or valgus. Survivorship ranged from 74.2% to 79.3% with increased tibial varus, 90% with increased femoral varus, and 83.3% with femoral valgus. Two kinematic alignment (KA) studies with >10-year follow-up reported no survivorship concerns. Decreased short-term to mid-term survivorship was reported in 2 KA studies (10.5%). No long-term data existed for other alignment philosophies, and the largest personalized alignment series included only 338 TKAs. Conclusion: Most studies demonstrated excellent short-to-midterm (5-year) survivorship regardless of coronal component alignment. However, limited evidence suggests increased early revision risk with some personalized alignment philosophies and reduced long-term (>10 years) survivorship with nonmechanical component alignment. Until higher-quality, long-term evidence with aseptic survivorship as the primary outcome is available, mechanically aligned TKA remains the most extensively validated approach. Level of Evidence: Level II. See Instructions for Authors for a complete description of levels of evidence.