Association of lower muscle strength with self-reported knee instability in osteoarthritis of the knee: results from the Amsterdam Osteoarthritis cohort.
OBJECTIVE
To determine whether muscle strength, proprioceptive accuracy, and laxity are associated with self-reported knee instability in a large cohort of knee osteoarthritis (OA) patients, and to investigate whether muscle strength may compensate for impairment in proprioceptive accuracy or laxity, in order to maintain knee stability.


METHODS
Data from 283 knee OA patients from the Amsterdam Osteoarthritis cohort were used. Univariable and multivariable logistic regression analyses were performed to assess the association between muscle strength, proprioceptive accuracy (motion sense), frontal plane varus-valgus laxity, and self-reported knee instability. Additionally, effect modification between muscle strength and proprioceptive accuracy and between muscle strength and laxity was determined.


RESULTS
Self-reported knee instability was present in 67% of the knee OA patients and mainly occurred during walking. Lower muscle strength was significantly associated with the presence of self-reported knee instability, even after adjusting for relevant confounding. Impaired proprioceptive accuracy and high laxity were not associated with self-reported knee instability. No effect modification between muscle strength and proprioceptive accuracy or laxity was found.


CONCLUSIONS
Lower muscle strength is strongly associated with self-reported knee instability in knee OA patients, while impairments in proprioceptive accuracy and laxity are not. A compensatory role of muscle strength for impaired proprioceptive accuracy or high laxity, in order to stabilize the knee, could not be demonstrated.
Reade, Amsterdam, The Netherlands. j.knoop@reade.nl
Jesper
J
Knoop
Marike
M
van der Leeden
Martin
M
van der Esch
Carina A
CA
Thorstensson
Martijn
M
Gerritsen
Ramon E
RE
Voorneman
Willem F
WF
Lems
Leo D
LD
Roorda
Joost
J
Dekker
Martijn P M
MP
Steultjens
D000368:Aged; D001696:Biomechanical Phenomena; D016009:Chi-Square Distribution; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007593:Joint Instability / Q000209:etiology* / Q000503:physiopathology; D007719:Knee Joint / Q000503:physiopathology*; D016015:Logistic Models; D035002:Lower Extremity; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength; D018482:Muscle, Skeletal / Q000503:physiopathology*; D009426:Netherlands; D016017:Odds Ratio; D020370:Osteoarthritis, Knee / Q000150:complications* / Q000503:physiopathology; D011434:Proprioception; D018570:Risk Assessment; D012307:Risk Factors; D057566:Self Report