Laxity in healthy and osteoarthritic knees

Abstract

Greater varus-valgus laxity in the uninvolved knees of OA patients versus older control knees and an age-related increase in varus-valgus laxity support the concept that some portion of the increased laxity of OA may predate disease. Loss of cartilage/bone height is associated with greater varus-valgus laxity. These results raise the possibility that varus-valgus laxity may increase the risk of knee OA and cyclically contribute to progression.

Association of lower muscle strength with self‐reported knee instability in osteoarthritis of the knee: Results from the Amsterdam Osteoarthritis Cohort

“…Muscles around the knee are presumed to be major stabilizers of the knee joint (20,22) and are considered to play a crucial role in knee stability in patients with knee OA (2,8,14,17,19). The presence of episodes of knee buckling has been found to be related to weaker lower extremity muscle strength in a large study cohort (but not exclusively knee OA patients) (1).…”

“…Frontal plane (varus-valgus) laxity has never been found to be associated with self-reported knee instability (3,4,6,13). Because episodes of knee instability might mainly represent movements in the sagittal plane, sagittal plane laxity (17,45,46) could be more strongly related to self-reported knee instability, compared to frontal plane laxity. Unfortunately, no study has focused on the relationship between sagittal laxity and knee instability.…”

“…This lack of evidence for interactions between biomechanical factors may be caused by the lack of any association between proprioceptive accuracy and laxity and self-reported instability. Interactions between muscle strength and proprioceptive accuracy (19,22) and between muscle strength and laxity (8,14,17) have frequently been proposed in knee OA literature when concerning knee stability, but have never actually been demonstrated. Studies by our own study group (14,19) demonstrated that in persons with impaired proprioceptive accuracy or with high varus-valgus laxity, a decline in muscle strength resulted in a stronger deterioration in activity limitations compared to persons with adequate proprioceptive accuracy or low laxity.…”

“…Biomechanical impairments such as muscle weakness, impaired proprioceptive accuracy, and high laxity, which are frequently present in knee OA patients (15)(16)(17)(18), have been regularly hypothesized as important causal factors in self-reported knee instability (1,2,4 -6,13,14,19). Quadriceps and hamstring muscles are considered to be principal stabilizers of the knee joint by absorbing shock forces and modifying knee joint load (8 -10,20 -23).…”

“…Strong lower extremity muscles are suggested as being structures able to stabilize the knee, even when proprioceptive accuracy is impaired or laxity is high (2,8,14,17,19). Studies by van der Esch et al (14,19) in knee OA patients showed that in persons with impaired proprioceptive accuracy or high laxity, muscle strength was more strongly related to activity limitations than in persons with adequate proprioceptive accuracy or low laxity.…”