Osteoarthritis and cartilage / OARS, Osteoarthritis Research Society. 2014;22(4):527-534.
OBJECTIVE: Knee buckling, in which a knee gives way during weight-bearing, is common
in people with knee pain and knee osteoarthritis (OA), but little is known about the
prevalence of sensations of knee instability, slipping or shifting in which the knee
does not actually buckle, or of the psychosocial and physical consequences of these
symptoms. DESIGN: We asked participants in the Multicenter Osteoarthritis Study separately
about episodes of knee buckling and sensations of knee instability without buckling
in the past 3 months, and assessed fear of falling, poor balance confidence (ABC Balance
Scale ≤ 67/100), activity limitation due to concern about buckling, and poor physical
function (WOMAC physical function ≥ 28/68). We used Poisson regression to estimate
prevalence ratios for cross-sectional associations of buckling and sensations of instability
without buckling with these outcomes, adjusting for confounders. RESULTS: Of 2,120
participants (60% female, 40% ≥ 65 years, mean BMI: 31 kg/m258), 18% reported buckling,
27% had sensations of knee instability without buckling, and 9% reported both symptoms.
Buckling and sensations of instability without buckling were each significantly associated
with fear of falling, poor balance confidence, activity limitations, and poor WOMAC
physical function. Subjects who reported both buckling and instability without buckling
and those with at least 2 buckling episodes (15%) had the strongest association with
poor outcomes. CONCLUSIONS: Knee buckling and especially sensations of knee instability
without buckling were common and each was significantly associated with fear of falling,
poor balance confidence, activity limitations, and poor physical function.