Tibial Slope is Not Associated with Implant Migration Following Cemented Total Knee Arthroplasty With a Single Implant Design

C Glen Richardson; Matthew J Kivell; Michael J Dunbar; Elise K Laende

doi:10.1016/j.arth.2024.04.021

Tibial Slope is Not Associated with Implant Migration Following Cemented Total Knee Arthroplasty With a Single Implant Design

J Arthroplasty. 2024 Apr 25:S0883-5403(24)00333-4. doi: 10.1016/j.arth.2024.04.021. Online ahead of print.

Authors

C Glen Richardson¹, Matthew J Kivell¹, Michael J Dunbar¹, Elise K Laende²

Affiliations

¹ Division of Orthopaedics, Department of Surgery, Dalhousie University and QEII Health Sciences Centre, Nova Scotia Health Authority, Halifax, Nova Scotia, Canada.
² Division of Orthopaedics, Department of Surgery, Dalhousie University and QEII Health Sciences Centre, Nova Scotia Health Authority, Halifax, Nova Scotia, Canada; Mechanical and Materials Engineering, Queen's University, Kingston, Ontario, Canada. Electronic address: elaende@dal.ca.

PMID: 38677348
DOI: 10.1016/j.arth.2024.04.021

Abstract

Background: The influence of tibial slope on tibial component migration following total knee arthroplasty (TKA) has not been widely studied, although excessive posterior slope has been implicated in some failures. As implant micromotion measured with radiostereometric analysis can indicate successful fixation, the purpose of this study was to determine the associations between tibial slope, tibial component migration, and inducible displacement.

Methods: Radiostereometric analyses at six visits over two years quantified implant migration for 200 cemented TKAs. Longitudinal data analysis examined the influence of postoperative tibial slope on implant migration (overall maximum total point motion (MTPM) migration and anterior-posterior tilt migration), accounting for age, sex, and body mass index. The correlations of tibial slope with one-year migration, continuous migration, and inducible displacements were also examined. Additionally, the amount of change in slope was compared to migration.

Results: The mean posterior tibial slope was 8.0° (standard deviation (SD) 3.8°) preoperatively and 3.8° (SD 3.1°) postoperatively, with a mean reduction in slope of 4.2° (SD 4.7°). Postoperative tibial slope (range 14.0° posterior slope to 3.4° anterior slope) was not associated with longitudinal overall migration (P = 0.671) or anterior-posterior tilt migration (P = 0.704). There was no association between postoperative tibial slope and migration at one year postoperatively (P = 0.441 for MTPM migration, P = 0.570 for tilt migration), change in migration from one to two years (P = 0.951), or inducible displacement (P = 0.970 MTPM, P = 0.730 tilt). The amount of change in tibial slope was also not associated with migration or inducible displacement.

Conclusions: Residual and change in postoperative tibial slope were not associated with implant migration into tilt or overall migration, or inducible displacement for a single implant design. These findings support positioning tibial implants in a range of slopes, which may support patient-specific approaches to implant alignment.

Keywords: alignment; implant migration; radiostereometric analysis; tibial slope; total knee arthroplasty.