INTRODUCTION: The prevalence of ACL injuries is increasing in previous years. One of the most common studied kinematic risk factors related to ACL injuries is a resultant weak, leg axis alignment known as the dynamic knee valgus angle presented during a vertical drop jump [8, 14, 15]. Hewett et. al. concluded that a knee valgus angle was a primary predictor of the mechanism that leads to an ACL rupture [8]. By increasing the excessive knee valgus angle during a two-legged DVJ, an athlete is in turn increasing the possibility of a high knee valgus moment, which can increase the anterior tibial translation as well as the load on the ACL several-fold and the chances for an ACL tear [4]. METHODS: In our study, ten collegiate female participants, including ballet and non-ballet athletes performed two-legged DVJs for 6 different flexor and extensor muscles while digital recordings of knee valgus angle were captured at initial contact and push off with simultaneous collection of EMG data. RESULTS: Results displayed statistical significance for the average valgus angle to estimated GRF ratio for the non-dominant leg at push-off between the ballet and non-ballet athletes (0.8 ± 0.43 vs. 1.8 ± 0.33 degrees/N, p < 0.05). In addition, we also found that the hip extensor activity significantly increased for the non-ballet group and that the lateral thigh CCI noticeably increased for the non-dominant leg for the non-ballet group, which could be indicative of the noticeable difference in the biceps femoris muscle activation for the non-ballet group when comparing sports type. In addition, statistically significant interactions between sports type and leg type for vastus medialis and gluteus maximus were produced. Observed results also indicated that there was an increase in overall variability for the dominant leg of the non-ballet athletes amongst all studied muscles and for the non-dominant leg for the ballet group specifically studying the gluteus maximus muscle activity. DISCUSSION: Relatively, the non-ballet group could be at a higher risk for increase in femoral adduction, hip adduction, and tibial external rotation, and overall predict a larger knee valgus moment; therefore, the non-ballet group could potentially be at a higher risk for an ACL injury than the ballet group. In addition, there is potential in continued research of neuromuscular differences between ballet and non-ballet athletes to further investigate the vastus medialis and the gluteus maximus muscle activations as well as to investigate the knee valgus moment values.

Biomechanics research investigating the knee kinematics of youth participants is very limited. The most accurate method of measuring knee kinematics utilizes invasive procedures such as bone pins. However, various experimental techniques have improved the accuracy of gait kinematic analyses using minimally invasive methods. In this study, gait trials were conducted with two participants between the ages of 11 and 13 to obtain the knee flexion-extension (FE), adduction-abduction (AA) and internal-external (IE) rotation angles of the right knee. The objectives of this study were to (1) conduct pilot experiments with youth participants to test whether any adjustments were necessary in the experimental methods used for adult gait experiments, (2) apply a Triangular Cosserat Point Element (TCPE) analysis for Soft-Tissue Artifact (STA) correction of knee kinematics with youth participants, and (3) develop a code to conduct a Principal Component Analysis (PCA) to find the PCA-defined flexion axis and calculate knee angles with both STA and PCA-correction for youth participants. The kinematic results were analyzed for six gait trials on a participant-specific basis. The TCPE knee angle results were compared between uncorrected angles and another method of STA correction, Procrustes Solution, with a repeated measures ANOVA of the root mean square errors between each group and a post-hoc Tukey test. The PCA-corrected results were analyzed with a repeated measures ANOVA of the FE-AA correlations from a linear regression analysis between TCPE, PS, PCA-TCPE and PCA-PS angles. The results indicated that (1) youth experiments can be conducted with minor changes to experimental methods used for adult gait experiments, (2) TCPE and PS analyses did not yield statistically different knee kinematic results, and (3) PCA-correction did not reduce FE-AA correlations as predicted.

The total knee arthroplasty (TKA) has become one of the most successful procedures in all of medicine, with an average of over 966,000 operations performed a year. Since its introduction in 1968, the TKA’s surgical process and implant designs have continuously been improved to increase survivability. However, the need for a revision TKA – due to aseptic loosening – continues to be a problematic aspect of the procedure. Stress shielding induced by different design parameters of the implant has generated controversy in the determination of an ideal configuration. The purpose of this study is to investigate how implant design parameters – fixation technique, stem geometry, cement stiffness, and interface condition – affect the stress shielding within the tibia, and to find an optimal combination of designs that mitigates stress shielding. A CT scan of a tibia was used to simulate multiple configurations of TKAs for finite element analysis in ABAQUS. Stress shielding was assessed by taking the average minimum principal stress of different regions at interval cuts along the depth of the tibia. The results concluded a short, full-cement stem to be the ideal combination of stem length and fixation technique, high-stiffness cement to be ideal for hybrid cements, low-stiffness cement to be ideal for full cements, and a sliding friction interface to be ideal for all models.

Osteoarthritis (OA) is a degenerative disease of cartilage and bone tissue and the most common form of arthritis, accounting for US$ 10.5 billion in hospital charges in 2006. Obesity (OB) has been linked to increased risk of developing knee OA due to increased knee joint loads and varus-valgus misalignment. Walking is recommended as a weight-loss activity but it may increase risk of knee OA as OB gait increases knee loads. Cycling has been proposed as an alternative weight-loss measure, however, lack of studies comparing normal weight (NW) and OB subjects in cycling and gait hinder identification of exercises that may best prevent knee OA incidence. The objective of this work is to determine if cycling is a better weight-loss exercise than gait in OB subjects as it relates to knee OA risk reduction due to decreased knee loads. A stationary bicycle was modified to measure forces and moments at the pedals in three dimensions. A pilot experiment was performed to calculate resultant knee loads during gait and cycling for NW (n = 4) and OB (n = 4) subjects. Statistical analyses were performed to compare knee loads and knee angles, and to determine statistical significance of results (p < 0.05). Cycling knee loads were lower than gait knee loads for all subjects (p < 0.033). OB axial knee loads were higher than NW axial knee loads in gait (p = 0.004) due to the weight-bearing nature of gait. No differences were observed in cycling knee loads between NW and OB subjects, suggesting cycling returns OB knee loads and biomechanics to normal levels. The lack of significant results in cycling could be due to the small sample size used or because rider weight is supported by the seat. Limitations to this study include small sample size, soft tissue artifact, and experimental errors in marker placement. Future studies should correct these limitations and find knee joint contact force rather than knee resultant loads using v EMG-driven experiments. In conclusion, cycling loads were lower than gait loads for NW and OB subjects suggesting cycling is a better weight-loss exercise than gait in the context of reducing knee OA risk.

BACKGROUND: There has been an enormous rise in total joint arthroplasties (TJA) in the United States over the past several years. Researchers have documented the increase in healthcare costs associated with unplanned hospital readmissions among patients post-TJA, specifically total hip and total knee arthroplasties. Additionally, researchers have reported the burden that these costs place on the healthcare system, private payers and on patients and their caregivers. Social routines, quality of life and occupational functioning are often interrupted because of a patient’s unplanned hospital readmission after receiving a total hip or total knee arthroplasty. Investigators have identified the major causes of costly unexpected hospital readmissions among patients with a TJA; they include surgical site infections, blood clots, joint dislocations and periprosthetic fractures. The Occupational Therapy Practice Framework: Domain and Process describes the practice of occupational therapy as promoting health, well-being, and engagement in meaningful occupation. Nonetheless, there is limited literature in the occupational therapy field directed towards reducing hospital readmissions among patients with a total hip or knee arthroplasty, thus suggesting an area that is well-positioned for intervention development and testing. PURPOSE: This Occupational Therapy Doctoral Project entitled Teaching Intervention to Reduce Readmissions-Post Surgery (TIRR-PS) is a proposed program for an acute care hospital setting which: (a) described the problem of hospital readmissions among patients with a total hip or total knee arthroplasty, (b) investigated evidence and best practices for imparting knowledge and/or teaching skills to hospital administrators, healthcare professionals, occupational therapy staff, patients, and caregivers, (c) proposed an intervention based on empirically supported strategies and theoretical frameworks, (d) recommended activities to include as part of the program evaluation, the funding plan and the dissemination plan to promote this multi-level, multi-component pilot program. TIRR-PS will aim to reduce unplanned 30-day hospital readmissions and their associated healthcare costs. Unplanned readmissions are in part caused by inadequate education of hospital administrators, occupational therapy staff, patients, and caregivers. The TIRR-PS program will raise awareness about how to address common medical complication risks and promote the support of hospital administration for the education and skill building activities directed towards healthcare professionals with an emphasis on occupational therapy. CONCLUSION: TIRR-PS was designed for an acute care setting to reduce hospital readmission rates, to reduce healthcare costs, to improve patient quality of life, and to reduce the societal burden of unplanned hospital care. TIRR-PS is an innovative program designed to be comprehensive and to impart knowledge and skills to all relevant professionals in an acute care setting with a particular emphasis on the contribution of the OT profession. TIRR-PS, once evaluated, will provide a standardized, systematic approach to reducing unexpected hospitalizations post-TJA and shows promise for contributing to routine orthopaedic rehabilitative practice in acute care hospitals. This in turn will not only reduce healthcare costs, but will improve the post-surgery quality of life for patients with a recent total hip or total knee arthroplasty.

While tremendous advances have been made in prosthesis technology, a greater understanding of amputee gait is needed, especially among amputees in developing countries. Field studies as well as prosthesis technology in developing countries are limited due to barriers associated with equipment and resources availability. Furthermore, individuals with lower limb amputation experience increased difficulty walking and a higher fall rate compared to non-amputees, which may be exacerbated by environment, terrain, or prosthesis componentry. Due to the importance of walking on various terrain for increased quality of life as well as the differences between prosthesis technology available in developing and developed countries, a better understanding of amputee gait on underdeveloped outdoor terrain is needed. We began to address these needs with three studies that explored factors that influenced and predicted amputee gait on realistic end-user outdoor terrain. First, we investigated the effects of environment (i.e. indoor laboratory or outdoor natural walking path), terrain, and amputation level on energy expenditure and dynamic stability while walking among lower limb amputees and non-amputees. We found that terrain and amputation level affected amputee energy expenditure and stability while environment and specific uneven terrain type had minimal effects. These results may guide future work investigating the effects of terrain in laboratory-based studies. Second, we investigated the ability to predict quantitative measures of amputee gait on outdoor underdeveloped terrain from laboratory-based measurements. We found individual participant characteristics and easily accessible measures of indoor gait were as or more effective at predicting energy expenditure and dynamic stability than gait measures requiring greater experimental and analytical resources. These results may offer a tool for researchers to assess performance among amputees in various settings without the need for expensive and technical equipment. Third, we examined the effect of a low-cost prosthetic knee joint on amputee gait. Specifically, we investigated the effects of on energy expenditure, gait stability, and perceptions of the low-cost prosthetic knee joint while walking on indoor and outdoor terrains. We found evidence that the low-cost knee increased energy expenditure and increased some characteristics of dynamic stability while decreased others. Furthermore, we also identified key insights among amputees about the performance of the low-cost prosthetic knee joint that could aid in future design modifications of the knee. Together, these studies help to clarify differences in walking performance between laboratory and outdoor terrains among lower limb amputees, help circumvent the challenges of obtaining quantitative gait measures during field studies in developing countries and may help guide the future design and use of low-cost prosthetic knee technology. / Doctor of Philosophy / While tremendous advances have been made in prosthesis technology, a greater understanding of how lower limb amputees walk (i.e. amputee gait) is needed, especially among amputees in developing countries. Studies in the field as well as the devices that amputees where to walk (prosthesis technology) in developing countries are limited due to barriers associated with equipment and resources availability. Furthermore, individuals with lower limb amputation experience increased difficulty walking and a higher fall rates compared to non-amputees, which may be exacerbated by environment, terrain, or components of the prosthesis. Due to the importance of walking on various terrain for increased quality of life as well as the differences between prosthesis technology available in developing and developed countries, a better understanding of how amputees walk on uneven outdoor terrain is needed. We began to address these needs with three studies that explored factors that influenced and predicted how amputees walk on realistic end-user outdoor terrain. First, we investigated the effects of environment (i.e. indoor laboratory or outdoor natural walking path), terrain, and amputation level on energy expenditure and walking stability among lower limb amputees and non-amputees. We found that terrain and amputation level affected amputee energy expenditure and stability while environment and specific uneven terrain type had minimal effects. These results may guide future work investigating the effects of terrain in laboratory-based studies. Second, we investigated whether we could predict amputee walking performance on outdoor underdeveloped terrain from laboratory-based measurements. We found individual participant characteristics and easily accessible performance measures were as or more effective at predicting energy expenditure and stability than performance measures requiring greater experimental and analytical resources. These results may offer a tool for researchers to assess performance among amputees in various settings without the need for expensive and technical equipment. Third, we examined the effect of a low-cost prosthetic knee joint on amputee gait. Specifically, we investigated the effects of on energy expenditure, gait stability, and perceptions of the low-cost prosthetic knee joint while walking on indoor and outdoor terrains. We found evidence that the low-cost knee increased energy expenditure and increased some characteristics of stability while decreased others. Furthermore, we also identified key insights among amputees about the performance of the low-cost prosthetic knee joint that could aid in future design modifications of the knee. Together, these studies help to clarify differences in walking performance between laboratory and outdoor terrains among lower limb amputees, help circumvent the challenges of obtaining quantitative gait measures during field studies in developing countries and may help guide the future design and use of low-cost prosthetic knee technology.

Abstract  Background One of the earliest signs of knee osteoarthritis (OA) is knee pain which correlates with inflammation and disease severity. Knee OA affects 260 million worldwide, and is in similarity with obesity, characterized by ongoing low-grade inflammation. The low grade-inflammation affects the knee-joint area and associations to cartilage degradation and bone remodelling have been shown. Most individuals, however, seek medical care for the first time when they experience knee pain. At this stage, the destruction of the knee is often irreversible. The inflammatory marker C-reactive can be found in both individuals who are obese and individuals with knee OA. It would be beneficial for the many individuals with knee pain at risk of developing knee OA, to be identified at an earlier stage and start treatment and hence slow down the progression of the disease.  Purpose  The purpose was to study associations between obesity, low-grade inflammation, self-reported knee symptoms and the outcome of radiographic knee OA in Swedish individuals with knee pain. Three research questions were formulated. Methods The design of this two-year longitudinal cohort study included Swedish individuals with present knee pain. Data was used to assess obesity and analyse inflammation to determine presence and/or severity of radiographic knee osteoarthritis and evaluate long- and short-term and symptoms and function of the knee. Original data were retrieved from the Cohort profile: the Halland osteoarthritis (HALLOA) cohort–from knee pain to osteoarthritis: a longitudinal observational study in Sweden. Individuals were recruited from healthcare clinics and newspaper advertisement. Age ranged from 32–63 and included data from 60 individuals after two years. Obesity was assessed where body composition was analysed with a bioelectrical impedance analysis. Level of C-reactive protein (CRP) was analysed with ELISA method. The outcome of radiographic knee OA was graded with Ahlbäck classification system in combination with physical examinations of the knees. Self-reported knee symptoms and function were measured with the questionnaire knee injury and osteoarthritis outcome score (KOOS). The data were analysed with the statistical computer software IBM SPSS Statistics.  Results No significant associations were found between the obesity, low-grade inflammation and the outcome of radiographic knee OA in Swedish individuals with knee pain. However, significant associations were found between the odds of developing radiographic knee OA assessed with KOOS for the subgroups pain (p = 0.032), symptom (p = 0.016), Sport/Rec (p = 0.02) and QOL (p = 0.038).  Conclusion KOOS questionnaire should be used for individuals with knee pain to identify individuals at risk of developing knee OA and ensue the disease progression, along with exercise and weight reduction if needed. CRP is not a good marker to measure inflammation in knee OA or use as a predictor tool.

Background: Historically the identification of ACL injuries upon initial presentation is low and considerable diagnostic delays have been reported. However, specific evidence on the individual elements of, and factors which influence delay, is lacking. Aims: The overarching aim was to provide a comprehensive picture of delay to diagnosis and specialist consultation, including factors which influence delay. An additional aim was to determine whether the approach to examining acute knee injuries varied as a consequence of varying patient presentation or experience of the assessing clinician. Methods: Study 1: Cross -sectional survey. Study 2: Non-participant direct observation methodology. Results: Data from 194 patients were analysed in the survey. Only 15.5% of patients were given a correct diagnosis of ACL rupture at the initial consultation. Median delay to diagnosis was 67.5 days (IQR= 15 to 178 days) and specialist consultation 108 days (IQR= 38 to 292 days). The factors most influential on delay were whether a follow-up appointment was arranged after attending A&E, whether the site of attendance operated an acute knee clinic and whether MRI was performed. The direct observation study showed wide variation in approach to injury assessment. Specialist clinicians performed the most comprehensive examination. A&E clinicians were more likely to assess for bony, neurovascular and gross tendon injuries as opposed to ligamentous or meniscal injury. Conclusions: The diagnostic rate of ACL injury at initial presentation remains low. Considerable delays to diagnosis and specialist consultation are apparent following ACL injury, the majority of which is attributable to health system delay.

Background Knee osteoarthritis is a degenerative joint disease characterized by damaged cartilage, tendons, ligaments, synovium, and bone. Knee osteoarthritis causes joint pain, reduced joint function, and decreased quality of life and is the leading cause of chronic disability in older adults. Two of the major risk factors for knee osteoarthritis are increasing age and obesity. To decrease the occurrence of knee osteoarthritis in our aging population, it is important that we identify exercises that are safe for people with or at risk of knee osteoarthritis. Purpose The main purpose of this thesis was to compare the acute response of knee cartilage composition to two common aerobic activities, running and bicycling, of equal total load. To address the primary purpose, we first sought to determine the reliability and validity of measuring loading repetition during running (steps) and bicycling (pedal-revolutions) using accelerometry. Methods 1) Twenty-two healthy adults completed running and bicycling activity bouts (five-minutes) while wearing six accelerometers: two at each the waist, thigh and shank. Accelerometer and video data were collected during each activity. 2) Fifteen healthy men completed running and bicycling activities of equal cumulative load that were preceded and followed by a series of magnetic resonance images. Results 1) Excellent reliability (ICC≥.99; SEM≤1.0) and validity (Pearson≥.99) were found for step and pedal revolution measurements taken by an accelerometer placed at the shank. 2) Bicycling did not cause significant changes in cartilage composition (p=0.274); however, running did cause a change in cartilage composition (p=0.002). Conclusion Findings from this thesis suggest that to acquire reliable and valid step and pedal revolution measurement, accelerometers should be placed on the shank. Furthermore, bicycling causes no statistical changes in knee cartilage, while running does. Bicycling may therefore be used to combat obesity and maintain cardiovascular health in individuals with compromised joint health. / Thesis / Master of Science (MSc) / Knee osteoarthritis is a degenerative joint disease that affects all knee tissues, particularly articular cartilage. This “wear and tear” condition reduces mobility and creates pain, collectively decreasing quality of life. Two important risk factors for knee osteoarthritis are age and obesity. While we cannot stop aging, exercise can have a positive impact on weight, particularly among adults with knee osteoarthritis. This thesis provides foundational information on how running and bicycling affects knee cartilage. First, we identified a useful method of measuring steps during running and pedal revolutions during bicycling. Second, we compared the effect of running and bicycling of equal cumulative load on knee cartilage, using MRI. The running activity was 1/3 the length of the bicycling activity but despite shorter exposure, running caused changes in cartilage shape and composition, while bicycling did not. These findings suggest that bicycling is a suitable aerobic activity that reduces loading at the knee.

Background: Knee osteoarthritis (OA) is the most common form of arthritis in older adults. Knee OA is associated with limitations in physical function. Functional limitations are also associated with another geriatric condition, frailty. Frailty is characterized by reduced strength, endurance and physiological function. Purpose: The primary purpose of this study is to determine if there is a difference in radiographic or symptomatic knee OA severity between non-frail and pre-frail women with knee OA. Secondary objectives include: a) the relationship between radiographic and symptomatic OA severity with serum inflammatory cytokines, and b) if there is a difference in inflammatory cytokines between non-frail and pre-frail women with knee OA. Methods: We included 21 community-dwelling women with knee OA. Frailty was assessed using the Fried Frailty Phenotype. Knee OA severity was characterized by the Kellgren and Lawrence (KL) score and the Knee Injury and Osteoarthritis Outcome Questionnaire (KOOS). Inflammatory cytokines included serum interleukin-6 (IL-6), interleukin-10 (IL-10), tumor necrosis alpha (TNF α) and C reactive protein (CRP). Results: Data from 20 participants (66.1 [9.6] years, BMI 29.7 [4.9] kg/m2, non-frail=55%; pre-frail=45%) were analyzed. Radiographic severity was not different between frailty groups (p= 0.11). There was no difference in symptomatic knee OA severity, measured using the KOOS subscales, between frailty groups (p>0.17). Radiographic OA severity and inflammatory markers were not associated (p>0.30). There was a negative relationship between TNF α and self-reported pain (r=0.26), no relationships between inflammatory cytokines with any other KOOS sub-scales. Lastly, there was no difference in any inflammatory cytokines between non-frail and pre-frail groups. Conclusion: Despite the relatively young age, nearly 50% of our participants were pre-frail. Pre-frailty was unrelated to the severity of the knee OA, or inflammatory cytokines. TNF α may be involved in the experience of pain in these women. While it appears women with knee OA frequently demonstrate pre-frail status, more work is necessary to examine the link between these diseases. / Thesis / Master of Science (MSc) / Arthritis is a chronic disease that has a debilitating effect on the lives of more than 4.6 million Canadians. In 2015, the cumulative economic burden of osteoarthritis was 195.2 billion dollars and is expected to increase significantly in the next two years. Knee osteoarthritis is the most common form of arthritis in older adults. Knee osteoarthritis is associated with increased pain, decreased physical function and decreased quality of life (QOL). In vulnerable older adults increased exhaustion, decreased physical function and muscle loss can increase the risk of developing frailty. Frail older adults are at higher risk of adverse health outcomes such as falls, hospitalization and death. Previous research has shown that older adults with knee OA are at higher risk of developing frailty however, it is not understood what underlying mechanisms increase this risk. This thesis provides fundamental information aimed at understanding potential mechanisms associated with knee osteoarthritis and frailty in women. Our study found that despite their relatively young age, nearly half of the women with knee OA are pre-frail. This data shows that inflammatory cytokines in particular, tumor necrosis factor alpha is related to symptomatic knee osteoarthritis severity in particular, self-reported pain. Overall, early detection of frailty is important when managing this condition. These data suggest that chronic knee pain associated with OA may be a useful trigger for early assessments of frailty in women.