Article

Postural balance (PB) is frequently used as an outcome measure in clinical and
research settings when assessing patients with knee osteoarthritis (OA). Pain and
stiffness is known to affect PB, and is elevated in the morning and evening in OA
patients. The aim of this study was to explore if time-of-day affects PB control
in knee OA patients. Centre Of Pressure (COP) excursion was measured (100Hz) by
force plate technique at selected time-points (9.00 a.m., 12.30 p.m. and 4.00
p.m.) during a single day in 32 knee OA patients aged 66.0 (10.3) years. A
rigorous protocol was followed to ensure comparable testing conditions across
time-points. PB control was quantified by the COP variables: velocity moment
(mm(2)/s), total sway area (mm(2)), total sway length (mm) and confidence ellipse
area (mm(2)). A two-way mixed-effects model showed that PB significantly improved
between 9.00 a.m. and 12.30 p.m. in three out of four COP variables. The observed
improvement was 11.9% (p=0.011) for velocity moment, 12.2% (p=0.011) for total
sway area and 9.4% (p<0.001) for total sway length. PB appears to be impaired in
the morning relative to midday in knee OA patients. Thus, it is recommended that
time of assessment is standardized between sessions when assessing PB in clinical
and research settings in knee OA patients.
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Langue : ANGLAIS