Bilateral Frontal Plane Mechanics After Unilateral Total Knee Arthroplasty

Abstract 

Milner CE, O'Bryan ME. Bilateral frontal plane mechanics after unilateral total knee arthroplasty.

Objective

To compare frontal plane knee mechanics among the operated and nonoperated limbs after total knee arthroplasty (TKA) and a healthy control limb.

Design

A cross-sectional analysis with age-matched control group.

Setting

A biomechanics and sports medicine laboratory.

Participants

Subjects (n=16; 8 men, 8 women; mean age, 61±7y; height, 1.71±0.10m; weight, 87.5±15.1kg) and age-matched healthy controls (n=16; 8 men, 8 women; mean age, 63±7y; height, 1.7±.09m; weight 72.5±13.9kg).

Interventions

Not applicable.

Main Outcome Measures

Peak knee adduction angle, first peak knee adduction moment, and the frontal plane knee angle and moment at loading peak during the stance phase of walking.

Results

Peak knee adduction angle (P=.176), and the frontal plane knee angle (P=.116) and moment (P=.260) at loading peak were similar across the operated, nonoperated, and healthy control limbs. The first peak knee adduction moment was higher in the nonoperated limb when compared with the operated limb and with the healthy control (P=.003). First peak knee adduction moment was similar in the operated knee and the healthy control.

Conclusions

The greater first peak knee adduction moment in the nonoperated knee indicates a possible mechanism for the predictable deterioration of this knee after unilateral TKA of the contralateral knee.

Key Words: Adult, Aged, Arthroplasty, Replacement, knee, Gait, Kinematics, Kinetics, Rehabilitation

List of Abbreviations: ES, effect size, OA, osteoarthritis, TKA, total knee arthroplasty