Physiotherapy - Research Publications

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Author: CREABY, MARK × Author: Hinman, Rana × End date: 2013 × Start date: 2013 ×

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    Self-reported knee joint instability is related to passive mechanical stiffness in medial knee osteoarthritis
    Creaby, MW ; Wrigley, TV ; Lim, B-W ; Hinman, RS ; Bryant, AL ; Bennell, KL (BIOMED CENTRAL LTD, 2013-11-20)
    BACKGROUND: Self-reported knee joint instability compromises function in individuals with medial knee osteoarthritis and may be related to impaired joint mechanics. The purpose of this study was to evaluate the relationship between self-reported instability and the passive varus-valgus mechanical behaviour of the medial osteoarthritis knee. METHODS: Passive varus-valgus angular laxity and stiffness were assessed using a modified isokinetic dynamometer in 73 participants with medial tibiofemoral osteoarthritis. All participants self-reported the absence or presence of knee instability symptoms and the degree to which instability affected daily activity on a 6-point likert scale. RESULTS: Forward linear regression modelling identified a significant inverse relationship between passive mid-range knee stiffness and symptoms of knee instability (r = 0.27; P < 0.05): reduced stiffness was indicative of more severe instability symptoms. Angular laxity and end-range stiffness were not related to instability symptoms (P > 0.05). CONCLUSIONS: Conceivably, a stiffer passive system may contribute toward greater joint stability during functional activities. Importantly however, net joint stiffness is influenced by both active and passive stiffness, and thus the active neuromuscular system may compensate for reduced passive stiffness in order to maintain joint stability. Future work is merited to examine the role of active stiffness in symptomatic joint stability.
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    Sagittal plane joint loading is related to knee flexion in osteoarthritic gait
    Creaby, MW ; Hunt, MA ; Hinman, RS ; Bennell, KL (ELSEVIER SCI LTD, 2013-10)
    BACKGROUND: High mechanical loading has been consistently linked with medial tibiofemoral osteoarthritis, and is considered to play a central role in the pathogenesis of the disease. Evidence from healthy adults indicates that knee flexion kinematics may influence knee load. The purpose of this study therefore, was to investigate the association between knee flexion kinematics and indicators of joint loading during walking (peak moments and vertical ground reaction force), in individuals with medial tibiofemoral osteoarthritis. METHODS: In this cross-sectional study, 89 participants with painful medial tibiofemoral osteoarthritis completed three-dimensional walking gait analysis to measure stance phase ground reaction forces, knee joint moments, and knee flexion kinematics. FINDINGS: In stepwise regression, greater knee flexion excursion was associated with higher peak vertical ground reaction force, accounting for 10% of its variance (B=0.62 [95% CI 0.34, 0.89], P<0.001). Greater peak knee flexion was associated with a higher flexion moment, accounting for 44% of its variance (B=0.12 [95% CI 0.09, 0.15], P<0.001). No association was found between the knee adduction moment and knee flexion kinematics during walking. INTERPRETATION: Our data suggest that greater knee flexion is associated with higher joint loads in the sagittal plane (i.e. a higher peak knee flexion moment). However, knee flexion kinematics were not associated with the knee adduction moment - a proxy measure of medial compartment knee load. Thus, high knee flexion should be considered an undesirable gait characteristic with respect to knee load in individuals with medial tibiofemoral osteoarthritis.