2015 ISAKOS Biennial Congress ePoster #1454

Knee Biomechanics are Further from Normal in Males than in Females Following Total Knee Arthroplasty

Jodie Mcclelland, BPhysio(Hons), PhD, Fitzroy, VIC AUSTRALIA
Kate E. Webster, PhD, Melbourne, VIC AUSTRALIA
Julian A. Feller, FRACS, Melbourne, VIC AUSTRALIA

La Trobe University, Melbourne, Victoria, AUSTRALIA

FDA Status Not Applicable

Summary: Knee biomechanics in males with TKA are more different from normal than for females with TKA.

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Abstract:

Introduction

Total knee arthroplasty (TKA) consistently improves pain and quality of life for people with disabling knee osteoarthritis. However, there are wide discrepancies in the reported outcomes for patients. In order to provide clearer expectations for patients, there is a need to investigate whether patients with particular characteristics may expect specific outcomes following surgery. Pre-operative evaluations of function, and specifically knee biomechanics of walking, suggest that a person’s gender may play a role in determining their outcome from TKA surgery. Whilst there is limited information that suggests females may expect poorer long-term functional outcome, the effect of gender on knee biomechanics in patients with TKA has not been evaluated. We hypothesise that males with TKA will walk with knee biomechanics that are closer to that of unimpaired males than females with TKA compared to unimpaired females.

Methods

There were 126 participants: 86 participants were 12 months post TKA surgery and 40 control participants were matched to age (±2 years) and gender of TKA participants. A 10 camera Vicon motion analysis system was used to collect video data from 24 retroreflective markers placed at specific anatomical landmarks as participants walked at self-selected speed. Two embedded force platforms recorded ground reaction force data. Spatiotemporal parameters, peak knee flexion angle during stance phase, peak knee flexion angle during swing phase, peak knee flexion moment and peak knee adduction moment were recorded from five trials of level walking for each participant and combined to form group averages. Walking speed was compared between all four groups (male TKA, n=41; male control, n=18; female TKA, n=44; and female control, n=21) using a univariate analysis of variance. Peak knee biomechanics were compared between groups using the same analysis except that body mass index and walking speed were included as covariates. Post hoc analysis (Bonferroni) was performed for significant findings by comparing the male TKA group to the male control group, and the female TKA group to the female control group. The size of the difference between these groups was estimated by calculating Cohen’s d effect sizes (ES).

Results

There was a significant difference between the groups for all variables of interest. Post hoc analysis showed that there was a large difference between male TKA and male control participants for the knee flexion angle (ES=1.1), knee flexion moment (ES=0.9), and knee adduction moment (ES=1.5) during walking. In contrast, only the knee adduction moment was significantly different for the female TKA compared to the female control participants (ES=0.9).

Discussion

Contrary to our hypothesis, knee biomechanics in males with TKA appear to be further from normal than for females. Unimpaired males walk with greater knee flexion angles and moments than females, and therefore males with TKA may need to use more extreme degrees of flexion to be close to normal than females. These findings underpin the importance of developing interventions that aim to restore normal knee flexion during gait for people with TKA, which may be particularly pertinent for male patients.