Objective:

To compare the effects of kinematic alignment (KA) and mechanical alignment (MA) on knee kinematics and patient-reported outcomes one year after total knee arthroplasty (TKA).

Approach:

• Study Design: Single-center, double-blinded trial involving 39 patients assigned to MA and 33 to KA, with nine healthy controls.
• Assessment Methods: Three-dimensional treadmill gait analysis was conducted preoperatively and one year postoperatively, assessing six degrees of freedom of knee motion, walking speed, and the Forgotten Joint Score (FJS).

Key Findings:

• No statistically significant differences in knee kinematics between MA and KA during level or downhill walking one year post-TKA.
• Mean FJS at one year was 65 for KA and 52 for MA; among CPAK type 1 patients, it was 65 for KA and 44 for MA.
• Preoperative ROM positively correlated with postoperative FJS in KA patients (r = 0.5) but negatively in MA patients (r = -0.3).
• KA patients showed smaller kinematic deviations from healthy controls than MA patients.
• KA demonstrated slightly greater knee joint distraction than MA, particularly in CPAK type 1 alignment.

Limitations:

• Study did not reach prespecified sample size due to COVID-19-related losses to follow-up.
• Higher preoperative BMI in the MA group and younger healthy controls may affect results.
• Treadmill walking may not replicate real-world conditions.
• ANOVA post hoc analysis not formally validated.
• Eligibility restricted to patients with a maximum varus deformity of 5°, limiting generalizability.

Sources:

• Scientific Reports