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

Abstract

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. 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 <i>a priori</i> outcome was all-cause aseptic revision. Included studies underwent qualitative synthesis. 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. 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 II. See Instructions for Authors for a complete description of levels of evidence.