Comparison of Kinematic Alignment and Mechanical Alignment in Total Knee Arthroplasty: A Meta-analysis of Randomized Controlled Clinical Trials

Abstract

The aim of this study was to estimate whether kinematic alignment (KA) improves knee function or clinical outcomes compared with mechanical alignment (MA) in the short term after total knee arthroplasty (TKA). We searched the literature for randomized controlled trials published before January 2020 from PubMed, EMBASE, Google, Web of Science, Cochrane Library, and other databases. The observation markers included "The Western Ontario and McMaster Universities (WOMAC) Osteoarthritis Index," "Knee Society Score (KSS)," "Oxford Knee Score (OKS)," "combined Knee Society Score (KSS)," "Knee injury and Osteoarthritis Outcome Score (KOOS)," "European Quality of Life Measure-5 Domain-5-Level (EQ-5D-5L)," range of motion (ROM), lower limb alignment, ligament release, and complications. A total of 11 randomized controlled trial studies were included in the study. During the follow-up of 6-24 months, the KA-TKA group was superior to the MA-TKA group in terms of WOMAC scores, combined KSS, KSS, knee function scores, and knee range of flexion, but there was no significant difference in EQ-5D-5L, KOOS, KOOS (symptoms, pain, ADL, sports, and quality of life), complications, knee range of extension, hip-knee-ankle (HKA) angle, tibial component slope angle, lateral distal femoral angle (LDFA) or medial proximal tibial angle (MPTA) angle between the MA-TKA group and the MA-TKA group (P > 0.05). Our meta-analysis revealed that the incidence of ligament release in the MA-TKA group was higher than that in the KA-TKA group. This meta-analysis shows that the KA-TKA group had better clinical outcomes and knee range of flexion than the MA-TKA group at short-term follow-up.

Keywords: Alignment; Knee joint; Meta-analysis; Total knee arthroplasty.

Fig. 1

The kinetic characteristics of normal knee are governed by three axes. (Photo credit: Dossett HG, Swartz GJ, Estrada NA, et al. ¹³

Fig. 2

(A) Flow chart of literature processing. (B) The literature guide search and results.

Fig 3

Eleven articles underwent Risk‐of‐Bias Assessment summary.

Fig. 4

The funnel plot for the symmetrical may indicate a low publication bias.

Fig. 5

The forest plot for WOMAC (0–96 best–worst).

Fig. 6

The forest plot for Combined Knee Society score (KSS, 0–200 worst–best), Knee Society Score(0–100 worst–best), Knee function Score(0–100 worst–best).

Fig. 7

The forest plot for Oxford Knee Score(0–48 worst–best).

Fig. 8

The forest plot for knee injury and osteoarthritis score (KOOS, 0‐100 worst–best).

Fig. 9

The forest plot for EQ‐5D‐5L.

Fig. 10

The forest plot for HKA, LDFA, MPTA, tibial component slope and femoral rotation angle.

Fig. 11

The forest plot for extension/flexion range of knee.

Fig. 12

The forest plot for ligament release.

Fig. 13

The forest plot for complication. Major complications are defined as revision of knee joint or removal of prosthesis caused by various reasons; and other additional surgery treatments were classified as minor complications.