KINEMATIC VS. MECHANICAL ALIGNMENT

Six high quality studies (Young 2020, MacDessi 2020, Matsumoto 2017, Yoe 2019, McEwen 2020, Sarzaeem 2021) included to see if there is any difference between kinematic versus mechanical principle of total knee arthroplasty. Composite scores like WOMAC Total, HSS Total, KOOS Total, Oxford Knee Score, Forgotten Joint Score, SF-36, and other scores were evaluated. Patient functional scores like KSS Function, Range of Motion, WOMAC function, WOMAC Stiffness, Flexion and Extension, KOOS ADL, SF 36 and many other scores were compared. 

Among composite scores, two high quality studies (MacDessi 2020, McEwen 2020) show equivalent KOOS total scores, two high quality studies (Young 2020, McEwen 2020) show equivalent Oxford knee scores, three high quality studies (Young 2020, MacDessi 2020, McEwen 2020) demonstrate equivalent forgotten joint scores.

Functional scores show similar results to composite scores. Two high quality studies (Young 2020, Yoe 2019) show equivalent KSS function. Two high quality studies (MacDessi 2020, McEwen 2020) show equivalent extension, KOOS ADL, KOOS symptoms scores, KOOS QoL, KOOS Sports and KOOS Pain scores between two groups.

Benefits/ Harms of Implementation

There is no significant benefit of kinematic principle which often utilizes more resources than the mechanical alignment knee.

Outcome Importance

Composite and functional scores are equivalent in both groups.

Cost Effectiveness / Resource Utilization

Kinematic knee could be performed without specialized navigation or convinced computer-assisted programs. However, five out of six high quality studies included in the discussion utilized navigation, robotic, or computer assistance programs which add to the cost of care. There does not appear to be any benefit of extra cost in this scenario.

Acceptability

The acceptability of this recommendation is high. There are several high-quality studies showing equivalent outcome scores.

Feasibility

The feasibility of this recommendation is high. Some institutions may not have access to resources such as computer assistance or navigation. Since several high-quality studies show no difference in outcomes, the increased use of resources is of no benefit.

Future Research

Future research should include the use of kinematic and mechanical alignment and its limitations with varying degrees of deformity.