Introduction: Gait biomechanics are associated with knee osteoarthritis (OA) structural progression, but no studies have included: i) all three lower extremity joints, ii) non-frontal plane factors, iii) temporal loading patterns, and iv) progression from structural and symptomatic perspectives. This dissertation addressed gaps in our understanding of lower limb biomechanics and their implication for determining whether we have identified and are targeting the most effective biomechanical variables in the development and evaluation of conservative interventions to slow knee OA structural and symptom progression (progression to TKA). Methods: 54 patients with knee OA underwent baseline gait analysis. Three-dimensional hip, knee, and ankle angles and moments were calculated. Waveform characteristics were determined using Principal Component Analysis (PCA), and knee adduction moment (KAM) peak and impulse were calculated. At follow-up 5-8 years later, 26 patients reported undergoing total knee arthroplasty (TKA). Unpaired Student’s t-tests detected differences in baseline demographic and gait characteristics between TKA and no-TKA groups. Receiver operating curve analysis determined discriminative abilities of these differences. Stepwise discrimination analysis determined which multivariate combination best classified the TKA group. Logistic regression analysis determined the predictive ability of the multivariate model. Results: There were no baseline differences in clinical and spatiotemporal gait characteristics, but the TKA group showed significant gait biomechanical differences, including higher KAM magnitude (KAMPC1), less difference between early and mid-stance KAM (KAMPC2), higher KAM peak and impulse, reduced early stance knee flexion and late stance knee extension moments (KFMPC2), and reduced stance dorsiflexion moments (AFMPC4). The multivariate discriminant function with the highest classification rate (74.1%) combined KAMPC1, KFMPC2, and AFMPC4, with sensitivity of 84.6 and specificity of 71.4. A one-unit increase in the model score increased risk of progression to TKA six-fold. Conclusion: Higher KAMPC1 scores suggest higher overall loading during gait. Lower KFMPC2 and AFMPC4 scores suggest inability to unload the knee and therefore sustained loading. Interventions reducing overall load and altering patterns of loading (i.e. increase unloading) may reduce risk of progression to TKA. Future research should determine how components of the discriminant model can be altered conservatively, and what impact alterations have on the risk of progression to TKA.

Osteoarthritis (OA) of the knee affects between 5.4% and 38% of older adults and this prevalence is increasing as the population ages and becomes more obese. As health costs rise, it is important to have accurate and cost-effective methods to assess knee OA and the risk for OA. One risk factor for progression of knee OA is lower extremity (LE) frontal-plane malalignment. The first goal of this thesis was to assess the suitability of knee radiographs and LE photographs for the estimation of frontal-plane LE alignment. In the first study, several versions of the femoral shaft-tibial shaft (FS-TS) angle, assessed from knee radiographs, were compared to the hip-knee-ankle (HKA) angle, assessed from full-length radiographs. We concluded that the FS-TS angle is not a recommended substitute for the HKA angle, because the association between the two measures differs depending on alignment, OA severity and the method of determining the FS-TS angle. In the second study, the hip-knee-ankle angle determined from a pelvis-to-ankle photograph (HKA-P) was assessed for its ability to estimate the HKA angle. The HKA-P angle was reliable and highly correlated to the HKA. It therefore shows promise as an accurate and cost-effective assessment tool for the estimation of LE alignment. Commonly-used grading scales for the severity of knee OA seen on a radiograph emphasize just one feature of OA; therefore the second goal of this thesis was to assess the psychometric properties of the unicompartmental osteoarthritis grade (UCOAG), a composite scale which grades several features of OA in the tibiofemoral (TF) compartment. In the third and fourth studies, the reliability, validity and sensitivity to change of the UCOAG scale was assessed and compared to two commonly-used scales (Kellgren-Lawrence and Osteoarthritis Research Society International joint space narrowing). The UCOAG scale showed moderate to excellent reliability. All three scales demonstrated comparable validity and sensitivity to change. The UCOAG is therefore recommended for the assessment of OA severity and change over time. This research provides evidence for the use of accurate and cost-effective measures to assess LE alignment using photographs, and TF OA severity using radiographs, for clinical assessment and research purposes. / Thesis (Ph.D, Rehabilitation Science) -- Queen's University, 2013-09-26 13:21:06.097

Title: The influence of pharmacological substances from the SYSADOA group on knee osteoarthritis. Objectives: The aim of this work is to determine the effect of three - month usage of pharmacological substances from the SYSADOA group on the subjective perception of the difficulties associated with the knee osteoarthritis and on the reological changes in the joint. Methods: In collaboration with rehabilitation and orthopedic centres 18 probands with knee osteoarthritis in the second degree were obtained. These probands were divided into two groups - the experimetal group (including those who have taken Proenzi 3 plus) and the control group (including those who have taken placebo). With all the pacients the input clinical examination and the medical history were done. Probands had been using these preparations for twelve weeks. After this time, the changes in the subjective perception using the WOMAC test and reological changes in the joint were evaluated, using a special knee rheometer. Results: The results of objectively measured parameters clearly proved that the Proenzi 3 plus has a positive effect on the rheological properties of the knee osteoarthritis. The experimental group had a statistically significant improvement in both of these parameters, as opposed to the control group. Concerning...

This thesis examined the immediate biomechanical effects of valgus unloader brace application in participants with moderate medial compartment knee osteoarthritis during gait. Thirty-three individuals were prescribed a valgus unloader brace. 3D knee moments and angles were calculated during walking with and without the brace. Principal Component Analysis identified amplitude and temporal changes of the moment and angle waveforms during gait. Three groups were identified based on the change in knee adduction moment magnitude with brace application. Two-Way ANOVA tested for differences among groups and conditions in principal component scores, as well as discrete varus thrust values. There existed three subgroups of participants identified by different gait adaptations to brace application. The brace had temporal and magnitude effects on 3D kinetics and kinematics for the participant group. This study showed that the brace does not provide a consistent change to knee joint mechanics. These results have implications for brace prescription.

Background and Purpose: Self-efficacy plays a major role in determining physical function during the earlier stages of the knee osteoarthritis (OA) and it may be a significant factor in the maintenance of physical function across the span of OA severity. This study examined the contribution of self-efficacy to objective and subjective measures of physical function at both maximal and sub-maximal levels. The relationship between self-efficacy and quality of life was also examined. Participants: Twenty community-dwelling adults with knee OA (age 69±14 years) were recruited for this study. Methods: Subjective maximal and sub-maximal performance were determined using the Maximal Activity Score (MAS) and Adjusted Activity Score (AAS) respectively of the Human Activity Profile. The objective measure of sub-maximal physical function was the 6-minute walk test (6MWT) while the Incremental Shuttle Walk Test (ISWT) was the maximal measure. Quality of life was determined using the Short Form Health Survey 36 (SF-36) and self-efficacy was measured using the Arthritis Self-Efficacy (ASE) scale. Disease severity was determined using the Western Ontario and McMaster University Osteoarthritis Index (WOMAC). A stepwise multiple linear regression analysis was performed using each of 6MWT, ISWT, AAS and MAS as the dependent variable, and the WOMAC and ASE as independent variables. Results: Self-efficacy explained 44% of the variance in the 6MWT but only 16% in the ISWT. Self-efficacy explained approximately 30% of the variance in both the MAS and AAS. A moderate relationship was observed between self-efficacy and the Physical Component Score (PCS) (r=0.51) of health-related quality of life, but no relationship was observed with the Mental Component Score (MCS). Discussion and Conclusion: In mild to moderate knee OA, sub-maximal physical function was substantively influenced by an individual’s belief in his/her ability to perform a given task, but not so when the intensity of the activity approached maximal levels. This differential relationship between sub-maximal and maximal performance was not present using subjective reports of performance. These findings indicate that therapy utilizing training at sub-maximal levels in mild to moderate knee OA should focus on strategies for enhancing self-efficacy; whereas with training at relatively high intensities, less focus should be given to enhancing self-efficacy. / Thesis (Master, Rehabilitation Science) -- Queen's University, 2008-04-25 15:28:10.666

Thesis (Ph.D.)--University of Western Australia, 2007.

Thesis (doctoral)--Lund University, 1997. / Added t.p. with thesis statement inserted.

Thesis (Ph. D.)--University of Missouri-Columbia, 2008. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on June 4, 2009) Vita. Includes bibliographical references.

Thesis (doctoral)--Lund University, 1997. / Added t.p. with thesis statement inserted.

BACKGROUND: Up to 37% of people with knee osteoarthritis (OA) present with varus thrust, an abrupt and dynamic worsening of varus alignment during the load-bearing stages of gait. Varus thrust is associated with up to 4-fold increased odds of medial knee OA progression as well as worsening clinical outcomes. While the implications of varus thrust have been well studied, the neuromuscular factors related to varus thrust are still not well understood and many studies report contradictory findings. Additionally, many potential factors remain unstudied. This warrants further efforts to determine associations between neuromuscular factors and varus thrust. The purpose of this study is to investigate knee muscle strength and muscle activation during walking in relation to biomechanical measures of varus thrust. METHODS: Analyses of existing data from participants with and without knee OA recruited at three institutions were used for this study. All participants underwent gait analyses at their self-selected pace while kinematics, kinetics, and surface EMG data were collected. Quadriceps and hamstrings strength was measured using isokinetic dynamometry. Gait data were used to calculate adduction excursion and peak knee adduction velocity as measures of varus thrust. A custom MATLAB code was used to calculate the rate of force development of the quadriceps, and a muscular co-contraction equation was used to calculate co-contraction values for four antagonist muscle pairs (VL-LH, VM-MH, VL-LG, and VM-MG) from surface EMG data during walking. Correlational analyses were performed to assess associations of strength, rate of force development, and muscle co-contraction variables with measures of varus thrust. RESULTS: A total of 183 participants were enrolled, however, a varying number of participants were used for different analyses based on available data. Peak isokinetic quadriceps strength at 60 degrees/second and peak hamstrings strength at both 60 and 120 degrees/second were negatively correlated with knee adduction velocity in people with knee OA. This association was not observed for people without knee OA. VLLH and VMMH co-contraction indices during preactivation were positively correlated with knee adduction excursion. VLLG co-contraction during midstance was positively correlated with peak knee adduction velocity. Association between rate of force development and varus thrust variables was not significant. CONCLUSIONS: Lower isokinetic thigh muscle strength and greater preactivation during walking are related to greater magnitude of varus thrust measured using motion capture. These results advance our understanding of neuromuscular factors related to varus thrust and could inform future interventions to reduce thrust and prevent further progression of OA. / 2020-06-14T00:00:00Z