Effect of Postoperative Sagittal Component Alignment on Functional Outcome and Patient Satisfaction Following Primary Total Knee Arthroplasty

Abstract

Background: Sagittal component alignment is one of the key factors that affects knee biomechanics after total knee arthroplasty (TKA), and its correlation with functional outcome and patient satisfaction is not well established.

Objective: Primary TKA patients who have a more normal sagittal component alignment will have a better functional outcome and satisfaction.

Material and Methods: Prospective Observational Analytical study was done in department of Orthopaedics Hayatabad Medical Complex Peshawar from August 2022 to January 2023. Patients were included in the study by consecutive sampling, and a total of 120 patients who were undergoing primary unilateral TKA were selected. Femoral component sagittal alignment, posterior tibial slope and posterior condylar offset were evaluated on postoperative lateral knee radiographs. Functional outcome was determined by the Hospital for Special Surgery Knee Score, which was assessed preoperatively and 6 months postoperatively. At six months patient satisfaction was also evaluated. Descriptive and inferential statistical analysis, correlation analysis and multivariable regression analysis were conducted.

Results: The mean age was 64.2 ± 8.7 years. Mean HSS score improved from 48.6 ± 7.9 preoperatively to 86.4 ± 8.2 at six months (p < 0.001). Femoral alignment sagittal alignment was in the target range in 78 (65.0%) patients and posterior tibial slope was in the target range in 81 (67.5%) patients. Patients with the femoral component range within the target range scored higher in the HSS post-op scores than those with the femoral component out of the target range (89.1 ± 6.7 vs. 81.4 ± 9.4, p < 0.001). Posterior tibial slope was found to be similar. Overall, 91 (75.8%) patients were happy or very happy with surgery.

Conclusion: Sagittal component alignment was associated with better functional outcome and patient satisfaction after primary TKA.

Keywords: are total knee arthroplasty (TKA), sagittal alignment and the posterior tibial slope.