Comparison of kinematic and mechanical alignment techniques in primary total knee arthroplasty

Abstract

Background:This meta-analysis compared clinical and radiographic outcomes and complications of kinematic alignment (KA) and mechanical alignment (MA) techniques in primary total knee arthroplasty (TKA).Methods:All studies comparing the operation time, change in hemoglobin, length of hospital stay, postoperative complications, and clinical and radiographic outcomes as assessed with various measurement tools, from direct interview to imaging methods, in patients who underwent primary TKA through the KA or MA technique were included.Results:Six studies were included in the meta-analysis. The proportion of patients who developed postoperative complications (OR: 1.10, 95% CI: 0.49–2.46; P = .69) did not differ significantly between the KA and MA techniques. The 2 groups were also similar in terms of change in hemoglobin (95% CI: −0.38 to 0.34; P = .91), length of hospital stay (95% CI: −0.04 to 0.55; P = .10), hip-knee-ankle angle (95% CI: −1.76 to 0.75; P = .43), joint line orientation angle (95% CI: −4.27 to 4.23; P = .99), tibial component slope (95% CI: −0.53 to 3.56; P = .15), and femoral component flexion (95% CI: −2.61 to 7.57; P = .34). In contrast, operation time (95% CI: −27.16 to −3.71; P = .01), overall functional outcome (95% CI: 6.59–11.51; P < .0001), knee anatomical axis (95% CI: −1.38 to −0.01; P = .05), femoral component relative to the mechanical axis (95% CI: −2.47 to −1.40; P < .0001), and tibial component relative to the mechanical axis (95% CI: 1.56–2.95; P < .0001) were significantly different between the 2 groups.Conclusions:There were no significant differences in postoperative complications, change in hemoglobin, length of hospital stay, hip-knee-ankle angle, joint line orientation angle, tibial component slope, or femoral component flexion between the KA and MA techniques for primary TKA. However, the KA technique resulted in a significantly shorter operation time and better overall functional outcome than the MA technique, even though the femoral component was placed in a slightly more valgus position relative to the mechanical axis and the tibial component in a slightly more varus position with the KA technique.

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

“…Our meta‐analysis revealed that the rate of ligament release in MA‐TKA was higher than that in KA‐TKA ( P = 0.0008). Consistent with findings in previous studies 27, 31, 33, 36, 38–40 , we found that the KA‐TKA group had better knee function outcomes than the MA‐TKA group in terms of the WOMAC score, KSS, combined KSS, and KSS.…”

“…While relevant meta‐analyses have been published in recent years, these studies included randomized controlled trials, case reports, and systematic reviews 27, 31 . Two systematic reviewss 27, 31 have analyzed the kinematic and mechanical alignment techniques in TKA. These two meta‐analysess 27, 31 included retrospective observational studies and randomized controlled trials (RCTs).…”

“…Two systematic reviewss 27, 31 have analyzed the kinematic and mechanical alignment techniques in TKA. These two meta‐analysess 27, 31 included retrospective observational studies and randomized controlled trials (RCTs). Both authors agree that the KA‐TKA provided better functional outcomes in addressing pain and improving function.…”

Kinematic alignment in total knee arthroplasty

“…Meta-analysis compared the clinical and radiographic outcomes and complications between the KA and MA techniques in primary TKA and showed no significant differences in postoperative complications. The overall functional outcome was better in KA than in MA [49].…”

What Is the Possible Impact of High Variability of Distal Femoral Geometry on TKA? A CT Data Analysis of 24,042 Knees

“…Also, kinematically aligned TKA might address some of the aforementioned topics. However, clinical benefit still is controversially discussed [25,28,29] and because it is recommended to use computer navigation or patientspecific instruments to ensure accuracy, it likely adds cost to the procedure. Although our findings may suggest that additional releases likely are needed with off-the-shelf designs to address the anatomic differences between implant sizes and patients' anatomies, and these soft tissue releases may weaken supportive knee ligaments, there is no robust evidence of which we are aware that this results in compromises to pain relief or function.…”