Abstract
Kinematically aligned total knee arthroplasty (KATKA) was developed to improve the
anatomical alignment of knee prostheses, assisting in restoring the native alignment
of the knee and promoting physiological kinematics. Early clinical results were encouraging,
showing better functional outcomes than with mechanically aligned total knee arthroplasty
(MATKA). However, there have been concerns about implant survival, and follow-up at
10 years or more has not been reported. In addition, randomized controlled trials
(RCTs) comparing KATKA with MATKA have reported inconsistent results. The current
meta-analysis of RCTs with a minimum of 2 years of follow-up investigated the clinical
and radiological differences between KATKA and MATKA. A systematic review of the English
language literature resulted in the inclusion of four RCTs. The meta-analysis found
no significant difference in any of the following parameters: postoperative range
of motion for flexion (mean difference for KATKA − MATKA [MD], 1.7 degrees; 95% confidence
interval [CI], −1.4 to 4.8 degrees; p = 0.29) and extension (MD, 0.10 degrees; 95% CI, −0.99 to 1.2 degrees; p = 0.86); Oxford Knee Score (MD, 0.10 points; 95% CI, −1.5 to 1.7 points; p = 0.90); Knee Society Score (MD, 1.6 points; 95% CI, −2.8 to 6.0 points; p = 0.49); and Knee Function Score (MD, 1.4 points; 95% CI, −4.9 to 7.8 points; p = 0.66). In addition, there was no significant difference between KATKA and MATKA
in the rate of complications requiring reoperation or revision surgery (odds ratio,
1.01; 95% CI, 0.25–4.09; p = 0.99) or in the length of hospital stay (MD, 1.0 days; 95% CI, −0.2 to 2.2 days;
p = 0.092). KATKA did not increase the number of patients with poor clinical results
due to implant position, particularly for varus placement of the tibial component.
In this meta-analysis based on four RCTs with a minimum of 2 years of follow-up, KATKA
were only relevant to cruciate retaining TKA and could not be extrapolated to posterior
stabilized TKA. Patient-reported outcome measures with KATKA were not superior to
those with MATKA.
Keywords knee osteoarthritis - total knee arthroplasty - kinematically aligned - mechanically
aligned - outcomes
