# Effects of Walking Aids on Knee Adduction Moment After Total Knee Arthroplasty: A Gait Analysis Study

## TL;DR

This study finds that walking aids, especially rollators with forearm support, reduce knee stress in patients after knee replacement surgery.

## Contribution

The novel contribution is comparing different walking aids' effects on knee loading in both operated and contralateral knees post-TKA.

## Key findings

- Walking aids significantly reduced knee adduction moment (KAM) in both operated and contralateral knees.
- Rollators with forearm support reduced contralateral knee loading more effectively than double canes.
- Forward trunk tilt was negatively correlated with ground reaction force, indicating better offloading with rollators.

## Abstract

Background: Total knee arthroplasty (TKA) is a common intervention for treating end-stage knee osteoarthritis (OA). Postoperatively, altered biomechanics may increase the risk of OA progression in the contralateral knee. Knee adduction moment (KAM) is a key indicator of medial knee joint loading and is associated with OA progression. Walking aids are often prescribed to reduce joint stress during walking; however, their comparative effects on KAM in patients undergoing TKA remain unclear. This study aimed to evaluate the effects of different walking aids (double canes [D-canes], rollators without forearm support [rollators], and rollators with forearm support [F-rollators]) on KAM peak and impulse in both the operated and contralateral knees of patients after TKA using gait analysis.

Methodology: A cross-sectional study was conducted on eight women who underwent unilateral TKA. Participants walked under four conditions: no aid, D-canes, rollators, and F-rollators. A three-dimensional motion capture system measured the lower limb kinematics and kinetics. The primary outcomes were KAM peak and impulse for both knees. Secondary outcomes included ground reaction force in the vertical direction (GRF Z), forward trunk tilt angle, and lower limb joint angles. A two-way repeated-measures measures analysis of variance (ANOVA) was used for statistical comparisons.

Results: Walking aids significantly reduced the KAM peak and impulse in both the operated and contralateral knees compared with unaided walking (P < 0.001). In the operated knee, the KAM peak decreased by approximately 20% with all aids, whereas in the contralateral knee, reductions were 6% for D-canes, 16% for rollators, and 24% for F-rollators. Rollators and F-rollators more effectively reduced contralateral knee loading than D-canes (P < 0.001). A significant negative correlation was found between trunk forward tilt angle and GRF Z (ρ= -0.74, P < 0.001), suggesting that increased forward lean with rollators and F-rollators enhanced lower limb offloading. No significant changes were observed in knee varus angle or walking speed across conditions.

Conclusions: Walking aids, particularly F-rollators, effectively reduce KAM and offload the contralateral knee in patients after TKA. These findings suggest potential benefits for patients at risk of OA progression in non-operated knees.