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Knee osteoarthritis (OA) causes more disability in community dwelling older adults than any other condition. The high costs associated with treating this disability suggest that research needs to focus on ways of preventing the development and progression of knee OA using low cost interventions such as exercise and modifications to certain activities of daily living. One such activity of daily living that has been implicated in the OA disease process is normal level walking or gait. Those with medial compartment knee OA are known to make certain modifications in their gait patterns in an attempt to unload the diseased compartment of their knee. Two of these modifications include the tendency of those with knee OA to walk with an externally rotated foot, and to increase the activity of their lateral hamstrings, while decreasing the activity of their medial hamstring during gait. Therefore, this work attempted to clarify this relationship between foot position, lower extremity loading and hamstring muscle activation patterns during both level walking and lower limb exercise. First, the changes in lower extremity loading with both internal and external rotation of the foot during gait were investigated in a group of young healthy subjects. It was discovered that internal rotation increased the magnitude of both the adduction moment and the medial-lateral shear force at the knee; while external rotation decreased both these measures. This suggests that external foot rotation may be an effective compensation strategy for those with medial knee OA and internal foot rotation may be an effective compensation strategy for those with lateral knee OA. Second, the same study was then repeated in a group of knee OA subjects and age matched healthy normal subjects; but in this work, hamstring EMG was also collected along with the external knee loads. Hamstring EMG data was used to calculate the medial-lateral (M-L) hamstring activation ratio. An increased M-L activation ratio would indicate an internal muscle moment tending to load the medial compartment more than the lateral; while a low M-L activation ratio would tend to unload the medial compartment. Those with knee OA had an increased late stance knee adduction moment and a decreased M-L hamstring activation ratio as compared to the healthy control group. Also, external foot rotation decreased the late stance knee adduction moment, lateral-medial shear force at the knee, and M-L hamstring activation ratio for both groups; but, internal foot rotation did not increase these measures. Lastly, since it is apparent that the hamstring may play a role in unloading the diseased knee compartment, the M-L activation ratio was calculated with changes in foot position during lower limb exercise in young healthy subjects to determine if selective activation of the medial or lateral hamstrings was indeed possible. It was discovered that internal foot rotation increases the M-L hamstring activation ratio and external rotation decreases it. Foot rotation has the ability to shift the external loads on the knee to one side of the joint or the other, and it also has the ability to alter internal knee loads created by hamstring muscular activation. Therefore, foot rotation during gait and lower limb exercise may be an effective intervention that could be used to delay the onset and progression of knee OA, keeping older adults active and healthy much longer. / Thesis (Ph.D, Kinesiology & Health Studies) -- Queen's University, 2007-09-28 14:31:23.908

Epidemiological studies have identified kneeling as an occupational risk factor for knee joint osteoarthritis (KOA), but direct biomechanical evidence for this relationship is lacking. We hypothesize one mechanism by which prolonged static kneeling may cause KOA is by compromising the integrity of the knee joint thereby increasing knee joint instability, which manifests as altered ambulatory loading profiles. Therefore, the purpose of this exploratory study was to investigate the effect of sustained static kneeling on knee joint gait parameters. Ten healthy male subjects (24.1 years ± 3.5) volunteered for this study. Each subject’s dominant leg was instrumented with markers to track lower limb motion and with surface electromyography electrodes to record quadriceps, hamstrings, and gastrocnemius muscle activity. Subjects performed ten walking trials at a self-selected normal pace over a force plate embedded in the floor. They then performed a kneeling protocol of three bouts of ten minutes of kneeling, each separated by a five minute seated rest period. Subsequently, a set of ten walking trials were performed after a short rest and equipment verification period. The ground reaction force and motion data were used to calculate the peak knee adduction moments, knee flexion moments, and knee flexion angles during the stance phase. The total muscle activity for each muscle during a single gait cycle as well as the co-contraction of the medial thigh muscles and the lateral thigh muscles were calculated from the surface electromyography data. One-sample t-tests were run on the absolute value of the pre- and post-kneeling outcome measures. All outcome measures were different across conditions indicating that the loading patterns were altered, in no specific direction, as a result of the static kneeling protocol. These results offer preliminary evidence to support the epidemiological findings that thirty minutes of daily occupational kneeling is associated with a higher prevalence of KOA. Further investigation is required to explore the importance of post-kneeling recovery, posture-induced blood occlusion, and cartilage stress due to cumulative loading while kneeling, as well as to test the clinical significance of the present findings. / Thesis (Master, Kinesiology & Health Studies) -- Queen's University, 2008-08-11 23:30:10.708

Background: Sagittal plane external flexion moment in early stance has been reported to be both higher and lower in people with medial knee OA compared to control subjects. Purpose: Sagittal plane knee joint kinetics and kinematics were compared between people with medial compartment OA and healthy subjects. Subjects with OA and low pain scores were also compared to those with OA and moderate pain scores. Subjects: Forty people with medial knee OA and 40 age and sex matched control subjects. Method: Knee alignment and OA severity were measured from radiographs. Frontal and sagittal plane moments and knee flexion angle during gait were measured using a three dimensional motion analysis system and force plates. The Western Ontario McMaster Universities Osteoarthritis Index (WOMAC) was used to measure pain; this score was used to divide the OA group into low pain and moderate pain OA groups. The relationship between knee flexion moment in early stance and gait speed, knee flexion angle and pain was also determined. Results: Subjects with OA had lower gait speed and cadence, and higher double limb support time. Peak knee adduction moment (first 50% of the gait cycle) was higher in the OA group. The knee flexion moment in early stance did not differ between groups; however the knee extension moment in late stance was lower in the knee OA group. The moderate pain group walked more slowly than the low pain group. The knee adduction moment, sagittal plane moments and knee flexion angle in stance did not differ between OA groups. A positive correlation was found between knee flexion moment and knee flexion angle in early stance in the knee OA group; the correlations between knee flexion moment and pain and gait speed were not significant. Conclusion: No differences were found in the knee flexion moment or stance phase knee flexion angle between the groups compared in this study, and therefore the results do not contribute to resolution of the controversy in the literature. Participants with knee OA in this study had relatively mild to moderate disease severity, which may have contributed to the non-significant findings. / Thesis (Master, Rehabilitation Science) -- Queen's University, 2009-08-27 00:37:29.466

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The purpose of this study was to determine the effects of the McDavid Knee Brace on forward and backward running kinematics and ground reaction forces. The subjects were 10past history of knee problems or any other physical disabilities that could affect their performance. The subjects were unpaid volunteers. Stride length and stride frequency values were determined during forward and backward treadmill run under each experimental condition (with a brace and without a brace). An ANOVA indicated no significant knee brace effect for either forward or backward treadmill running stride length or stride frequency. In the second phase of this study, ground reaction forces were determined for each experimental condition. The ground reaction peak forces under each experimental condition were not significantly different during either forward or backward running. Other statistical analysis of other dependent variables of forward and backward running indicated no significant bracing effect for ankle, knee and hip angular acceleration, angular displacement and angular velocity. Within the limitation of this study it is concluded that the McDavid Knee Brace had no effect on forward or backward running kinematics or ground reaction forces. / School of Physical Education

The purpose of this study was to determine the effectiveness of the Augmented Soft Tissue Mobilization (A.S.T.M.) Rehabilitation Technique on total knee replacement patients. The specific measurements assessed were stride length (SL), stride frequency (SF), walking velocity, support time (ST), total time (TT), static and walking range of motion (ROM) of the hip, knee, and ankle, ground reaction forces (GRF), and torques. Fourteen subjects (Female = 7, Male = 7) completed the study. Subjects were randomly assigned to two experimental groups, the Traditional Therapy treatment or the A.S.T.M. treatment. There were five testing sessions: pre operation, 8 weeks, 12 weeks, 16 weeks, and 24 weeks post operation. On the 12 week test, the subject had completed their assigned of treatment protocol. Static ROM was derived from gonimetric measurements before each testing session. Stride length, stride frequency, velocity, time, and walking ROM were derived from accelerometer data. Statistical analysis using ANOVA revealed a significant change in all static ROM, SL, and ST. The data indicated that both groups of the Total Knee Replacement patients did improve their functional status from their status prior to surgery. In addition, the data indicated that the Augmented Soft Tissue Mobilization program and the Traditional Therapy program are equally acceptable rehabilitation techniques. / School of Physical Education

Separating the study of kinematic geometry of the human knee from the study of its behaviour under load provides insight into the complex relationship between form and function at the joint. The development of a three-dimensional mathematical model which examines the mobility and stability of the joint in sequence is described in this thesis. A previously proposed model of knee mobility, in which the ligaments and ar- ticular surfaces act as rigid constraints between the bones in a single degree-of- freedom spatial mechanism, was re-examined and its limitations addressed. A new geometric-numerical approach to solving the model kinematics, capable of handling both idealised and more anatomical representations of the articular surfaces, was developed. A database of specimen-specific motion and geometry was established, based on cadaver studies. Articular contact kinematics and ligament length patterns were also quantified. In experiment, all components of passive knee movement were found to be coupled to the flexion angle, providing justification for the underlying concept of the model of knee mobility. Specimen-specific models of mobility were successful in predicting the main fea- tures of passive knee motion through a full range of flexion. Incorporation of second order tibial articular surfaces permitted the prediction of physiological motion com- patible with more realistic contact point movement. Through incorporation of continuous three-dimensional arrays of extensible lig- ament fibres, a preliminary model of knee stability was formulated. Although in need of further refinement, sample predictions of joint behaviour during a/p drawer and axial rotation have demonstrated the potential of the model in highlighting the subtleties of ligament mechanics. It was concluded that the sequential approach is appropriate for the study of joint behaviour in three dimensions and that, based on the success of the analogous two-dimensional theory, it provides an invaluable tool in the study of joint mechanics in activity and in the design and assessment of surgical procedures for treating knee injury and disease.

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