Multidirectional motion occurs in total knee replacements (TKR), is a major factor in ultra high molecular weight polyethylene (UHMWPE) wear and is a requirement for wear tester and simulators. There are three ways the femoral component can move relative to the tibial component; sliding, rolling and gliding and these are defined by the slide to roll ratio. Previous wear tester research has investigated the effects of multidirectional motion and slide to roll ratio, individually but not combined. The project aim was to design a machine that combined multidirectional motion with variable slide to roll ratio. A three station wear testing machine was designed and built featuring flexion extension, variable anterior posterior translation, variable internal external rotation and a 2KN load per station. The TKR was simplified to a cylinder on flat. Lubrication was 25% bovine serum and each station had its own recirculation system. A million cycle validation test was successfully carried out on non-irradiated UHMWPE samples using a slide to roll ratio of 1 : 0.5 and the mean wear rate was 14.7mg/10^6 cycles. Polished areas and scratches from 3rd body abrasion were observed. Magnification revealed a fine ripple pattern with a 1-2 micron periodicity. Ripples were randomly oriented, perpendicular to the primary direction of motion and a small number were running parallel to the primary direction of motion, indicative of rolling motion. The results from the validation study show that the knee joint wear tester is capable of producing wear rates and wear mechanisms similar to those observed in other wear testers and knee joint simulators and has met the aim of the project.

Syfte och frågeställningar: Syftet var att genom en tvärsnittsstudie ta reda på om det fanns asymmetrier mellan dominant och icke-dominant ben hos skadefria kvinnliga fotbollsspelare gällande sagittal knälaxitet. Frågeställningar i studien var: Hur stor är den anteriora och posteriora knälaxiteten i dominant respektive icke-dominant ben uppmätt med KT-1000 vid belastningar på 20 lb, 30 lb samt vid ett manuellt maxtest i anterior riktning? Föreligger det någon sidoskillnad mellan dominant och icke-dominant ben gällande knälaxitet uppmätt med KT-1000 vid anteriora och posteriora belastningar på 20 lb, 30 lb samt vid ett manuellt maxtest i anterior riktning? Hur stor andel av deltagarna uppvisar en sidoskillnad av sagittal knälaxitet på ≥ 2 mm respektive ≥ 3 mm uppmätt med KT-1000 och hur är frekvensen fördelad mellan dominant och icke-dominant ben hos dessa? Metod: För att besvara syfte och frågeställningar genomfördes en tvärsnittsstudie där 56 kvinnliga fotbollsspelare inom division 1-2 deltog. Samtliga deltagare var ≥ 18 år, skadefria och hade spelat fotboll i minst 5 år. Mätinstrumentet KT-1000 användes för att registrera knälaxitet mellan dominant och icke-dominant ben. Alla mätningar utfördes av samma testledare och med samma mätinstrument och genomfördes i en standardiserad position inför träning. Statistiska beräkningar utfördes på belastningarna P-20/30 lb, A-20/30 lb, Total AP-20/30 lb samt ett manuellt maxtest. Data för knälaxitet registrerades och analyserades utifrån bendominans genom ett Mann Whitney U-test. Resultat: Resultatet visade på en liksidig knälaxitet av dominant och icke-dominant ben vid anteriora och posteriora mätningar. Medelvärden varierade mellan 1,91–2,91 mm i posterior riktning med en spridning på 1-4 mm. Motsvarande mätvärden i anterior riktning var 4,03–9,53 mm med en spridning på 4-19 mm. Inga signifikanta sidoskillnader framkom mellan dominant och icke-dominant ben men en ökad knälaxitet uppmättes i dominant ben vid samtliga belastningar i anterior riktning. En sidoskillnad på ≥ 2 mm visade sig hos 16,6-51,8 % av deltagarna beroende på vilken belastning som testades. Av dessa registrerades en ökad anterior knälaxitet i det dominanta benet hos 62,1-81,2 %. Slutsats: Genomförda mätningar av sagittal knälaxitet visade inga signifikanta skillnader gällande asymmetrier mellan dominant och icke-dominant ben hos kvinnliga fotbollsspelare. Vid belastningen A-MMT uppvisade drygt hälften av deltagarna en individuell sidoskillnad på ≥ 2 mm. Studien belyser vikten av ytterligare forskning för att kartlägga individuella sidoskillnader gällande sagittal knälaxitet. / Aim: The aim of the cross-sectional study was to find out if there were asymmetries between the dominant and non-dominant leg in non-injured female soccer players regarding sagittal knee laxity. The aims were: What´s the anterior and posterior knee laxity in the dominant and non-dominant leg measured with KT-1000 at loads of 20 lb, 30 lb, and a manual maximum test in anterior direction? Is there side-to-side differences in knee laxity between the dominant and non- dominant leg measured with KT-1000 at the anterior and posterior loads of 20 lb, 30 lb and with a manual maximum test in anterior direction? How many of the participants show a side-to-side difference of sagittal knee laxity of ≥ 2 mm and ≥ 3 mm measured with the KT-1000 and how is the frequency between the dominant and non-dominant leg of these distributed? Method: In order to answer the aim of the cross-sectional study 56 female soccer players from division 1-2 participated. All participants were ≥ 18 years old, no previous knee injury and had played football for at least 5 years. The KT -1000 instrument was used to measure knee laxity between the dominant and non-dominant leg. All measurements were performed by the same test leader, with the same test-instrument and in a standardized position. Statistical calculations were performed on loads P-20/30 lb, A-20/30 lb, Total AP-20/30 lb and a manual maximum test. Data for knee laxity were measured and analyzed by leg dominance through the Mann Whitney U-test. Results: The results of all participants showed an equivalent of knee laxity of dominant and non-dominant leg at the anterior and posterior measurements. Mean values ranged from 1.91 to 2.91 mm in the posterior direction (range of 1-4 mm). The corresponding measured values in the anterior direction were 4.03 to 9.53 mm (range 4-19 mm). No significant side-to-side differences were revealed between the dominant and non-dominant leg but an increased knee laxity was documented in the dominant leg at all loads in the anterior direction. Depending on the load 16.6 to 51.8 % of the participated had a side-to-side difference ≥ 2 mm. 62.1 to 81.2 % of these registered increased anterior knee laxity in the dominant leg. Conclusions: The measurements of sagittal knee laxity revealed no significant differences in the asymmetries between the dominant and non-dominant leg in non-injured female soccer players. At the A-MMT load over half of the participants revealed a side-to-side difference ≥ 2 mm. The study highlights the need for further research to identify individual side-to-side differences regarding sagittal knee laxity.

Access to abstract permanently restricted to Ball State community only. / Access to thesis permanently restricted to Ball State community only. / School of Physical Education, Sport, and Exercise Science

As a therapist within the multi-disciplinary setting, one is confronted with a wide array of pathology and diagnoses. Care is taken to optimize treatment outcomes and overall return of function to every patient admitted to the various rehabilitation facilities. Treatment is often standardized to ensure quality care benchmarked against outcome parameters. The aforementioned is also true for medical practitioners, pharmacists and other auxiliary service providers. Research is aimed at improving quality of care, finding and establishing the best practises through all hospitals and care facilities. Medical care has undergone a transformation over the past few decades with a strong emphasis being placed on protocols and procedures. Through applying standardized care, protocols and procedures, the researcher have come to realize that certain denominators within patient care have no prediction or outcome control. After more than a decade of treating patients in various rehabilitation settings the researcher have come to realize that one complaint exists with each and every patient under my care – pain. This was even more evident within the group of joint replacement patients. No two patients presented with the exact same pain profile or pain reports despite various commonalities such as anthropometric data (age, gender, length, mass), surgical procedure, attending physician, care facility, pathway exposure, diagnosis, radiographic findings and pharmaceutical intervention. If all the obvious factors were identical – what accounted for the different pain reports? This question is at the heart of the study – why do pain reports differ in the presence of so many similarities between patients? It soon became apparent that pain is recognized in the organic form. Organic pain can be measured and is expected with injury, illness or surgical intervention. The entire multi-disciplinary team is aware of organic pain and ready to intervene with medication, surgery and a pathway of care. All vigorously record organic pain and adapt treatment according to the pain levels as organic pain is real pain: real pain existing through exposure to real surgical intervention. Still the question remained: if all the factors prior to surgery, during surgery and after surgery were the same, why are patients experiencing and reporting very different pain levels? This question was the catalyst for the research and lead to keen focus during patient interviews. Every patient receiving an educational session prior to surgery had very vivid ideas about the pain they will experience post-operatively. The majority of patients formed pre-conceived notions about pain prior to undergoing surgery. They presented with a clear pain rating of what they expected to feel post-operatively. The pre-conceived pain rating was constructed in almost all the cases after some form of information obtained during consultation with their surgeon or a member of the multidisciplinary team. This pain notion existed as a tangible and measurable rating in the client’s mind prior to undergoing the knee replacement surgery. In select cases perceived pain was constructed as a result of information obtained from family or friends that underwent the same procedure while other clients constructed perceived pain due to a lack of information on the proposed surgery. It became evident that education or lack thereof on surgical interventions played a primary role in the construct of perceived pain. Patients were entering theatres for procedures and already experienced a form of perceived pain. If pain could be constructed prior to experiencing surgical intervention – can perceived pain then translate into actual organic pain and account for the variable pain reports post surgery? Against this backdrop, research was directed at understanding perceived pain and the factors that aid the construction of perceived pain. As education was found to be at the heart of every pain construct, the doctor-patient consultation was evaluated as a core component to ascertain the impact this relationship has on perceived pain. Measurement of perceived pain was also performed to conclude on the impact of this pain form on organic pain. The study is aimed at addressing the variant pain reports that no pathway or procedure can predict and provide for. It is an attempt to validate pain as constructed by the patient that impacts on their post-surgical pain ratings and behaviour. This research might contribute towards existing knowledge and understanding of the influence of doctor-patient interaction as well as the significance of this interaction on pain. As only scant research on perception of pain has been undertaken this research can prove insightful for further studies or as supplement to existing views and opinions. It can also serve as a foundation in developing practices that will manage pain by enhancing doctor-patient interaction in the health setting. / MA, Medical Sociology, North-West University, Vaal Triangle Campus, 2012

A suite of silica-undersaturated syenites outcrops along the margins of a monzogranite pluton emplaced in the Knee Lake greenstone belt at Cinder Lake, Manitoba. Alkali-feldspar syenitic pegmatite probably represents a cumulate unit derived from magma that subsequently evolved to fine-grained feldspathoid syenites. This evolution involved an increase in the degree of undersaturation from cancrinite-nepheline syenite to vishnevite syenite. Abundant calcite veinlets, showing a carbonatitic isotopic and trace-element signature, crosscut the pegmatite and are interpreted to have evolved from the syenites. The monzogranite and syenites gave similar radiometric ages (~2.72 Ga), but evidence of fenitization in the former suggests that the syenites are somewhat younger. The emplacement of these rocks was coeval with the collision of the North Caribou and North Superior superterranes during amalgamation of the Superior Province. The observed transition from granitic to alkaline magmatism is interpreted to mark the transition from a collisional to post-collisional tectonic regime.

A computational model for the prediction of articular and backside polyethylene (PE) wear of total knee replacements (TKRs) could enable the optimization of TKRs for the reduction of polyethylene wear, thereby improving the long term success of TKRs. A finite element model was developed for the TKR and the results were implemented in a computational wear model to assess PE wear. The wear factors of Archard’s wear law were identified by implementing the finite element simulation results along with knee simulator wear test results. Archard’s wear law was found to have insufficient accuracy for the purpose of optimization. Therefore, a novel computational wear model was developed by the author based on a theoretical understanding of the molecular behavior of PE. The model predicted result fell within the standard deviation of the independent knee simulator wear test results, indicating a high level of accuracy for the novel computational wear model.

Knee osteoarthritis (OA) is a degenerative joint condition characterized by progressive joint pain, swelling, and loss of muscle and joint function for which there is no known cure. Current research indicates that the most important modifiable risk factor for the development and progression of knee OA is obesity, a condition that is increasingly common in older adults. Established treatment guidelines for knee OA recommend regular exercise for disease management. However, for obese patients weight-bearing exercise elicits large joint forces that can exacerbate symptoms and influence disease progression. Using a new anti-gravity treadmill capable of generating a lifting force called lower body positive pressure (LBPP), obese patients with knee OA can engage in regular physical activity while minimizing joint loading. The aim of this study was to assess the effect of a 12-week, anti-gravity treadmill walking (AGTW) program on knee pain and function in obese older adults with knee OA. The alternate hypothesis was that there would be a difference between Knee Injury and Osteoarthritis Outcome Score (KOOS) results before and after the anti-gravity treadmill walking program. A group of 25 participants with a mean (SD) age of 64.2 (6.1) years and BMI of 33.0 (6.8) kg/m2 completed AGTW twice per week for 12 weeks at a body weight percentage that minimized knee pain. Knee symptoms and function (KOOS), knee pain during full weight-bearing treadmill walking (FTW), isokinetic quadriceps and hamstring muscle strength, cardiovascular fitness (YMCA submaximal cycle ergometer test), general health status (SF-12), and activity level (average daily pedometer readings) were assessed at baseline and following the completion of the 12-week program using paired t-tests and Wilcoxon signed rank sum tests (α = 0.05). Improvements between baseline and outtake were found in all KOOS subscales, as well as hamstring and quadriceps thigh muscle strength. Knee pain during full FWB and AGTW decreased following the 12-week program. No significant differences were found in cardiovascular fitness, SF-12 scores, or average daily pedometer readings. The results of this study suggest that anti-gravity treadmill walking increases thigh muscle strength, reduces knee pain, and increases functional capacity during daily activities, including FTW in older, obese individuals with knee OA. Anti-gravity treadmill technology has the potential to improve the health and functional capacity of at-risk knee OA individuals, and advance current methods of rehabilitation and long-term management of chronic symptomatic knee OA.

This research has investigated the influence of gait cycle, malalignment and overweight on total knee replacements using a finite element method. Dynamic and finite element models of fixed- and mobile-bearing implants have been created and solved; the fixed- and mobile-bearing implants demonstrated different performance on movement and contact pressure distribution in the tibio-femoral contact surfaces. More contact areas were found in the mobilebearing implant than in the fixed-bearing implant, but the maximum contact pressures were almost the same in both. The thickness of the tibial bearing component influenced the fixed- and mobile-bearing implants differently. A dynamic model of an implanted knee joint has been developed using MSC/ADAMS and MSC/MARC software. Stress shielding was found in the distal femur in the implanted knee joint. The stresses and strains in the distal femur were found to increase with body weight, especially during the stance phase. Serious stress shielding and more bone loss appear in condition of overweight. The increase of bone loss rate and stress in the distal femur with increase of body weight will result in a higher risk of migration of femoral component after total knee replacement. The peg size effect has been studied using this dynamic model; a longer peg with smaller diameter was found to be the best. Varus/valgus malalignment redistributed the tibio-femoral contact force and stress/strain distribution in the distal femur. The difference between contact forces on the medial and lateral condyle decreased in the valgus malalignment condition. Contact pressure increased in the varus/valgus malalignment condition in the dynamic models of both the fixed- and mobile-bearing implant. However, the mobile-bearing implant performed better in conditions of malalignment, especially malrotation. Body weight had less influence on the maximum contact pressure in the mobile-bearing implant.

We developed a novel approach that requires subjects to produce and finely tune ground reaction forces (GRFs) while standing. Using this method we were able to identify specific contributions of individual muscles and how these contributions change with the effects of age. One of the aims of this investigation was to determine whether electromyographic data in our findings was due to random muscle activation or representative of a neuromuscular control strategy. Ten healthy young adults (5 male, 5 female) with their dominant foot fixed within a boot mounted to a force platform participated twice in a target matching protocol, requiring subjects to control both the direction and magnitude of GRF along the horizontal plane while maintaining constant inferior-superior loads of 50% body-weight. Subjects were asked to manoeuvre a cursor with their dominant leg to match a series of targets projected on a screen. Targets appeared at random one at-a-time, separated by 30o around a circular trajectory. Subjects applied loads to the force platform in various horizontal directions to move the cursor while also controlling body weight. A successful target match required subjects to maintain 50% body weight and 30% of their peak horizontal load for one second. Electromyography (EMG) of eight muscles that cross the knee joint, ground reaction forces, and kinematic data were recorded for each successful match. EMG was normalized to percent maximum voluntary isometric contractions collected on an isokinetic dynamometer. Each target matching session was separated by two-three days. A random model, single measures intra-class correlation analysed the reliability for both test-retest and intra-day results, in addition to intersubject reliability. We observed moderate to high ICC values (0.60 – 0.993) for most muscles in most directions, indicating low within-subject variance. In addition, moderate to high between-subject reliability was observed in all eight muscle activation profiles, indicating subjects used similar neuromuscular control strategies to achieve the desired GRFs. Our findings support that groups who have undergone the same number of testing sessions can be compared, and that a single testing session is all that is required to compare neuromuscular control strategies used by a group to achieve target locations. The second aim of this investigation was to evaluate age related differences in neuromuscular control about the knee joint using our target match protocol. Thirty-three healthy adults (17 younger 24 years ±2, 16 older 59 years ±5), completed the same protocol evaluated above. The mean magnitude of muscle activity, specificity index, and mean direction of muscle activity were calculated in each target direction. Older adults presented with significantly lower strength in knee flexion and extension, hip abduction, and ankle plantar flexion. Significantly (p<0.25) higher mean activation magnitudes in the rectus femoris, vastus lateralis, vastus medialis, biceps femoris, semitendinosus, medial gastrocnemius, and tensor facia lata were also observed. Intraclass correlations (ICC) magnitudes indicate the percentage of global variance that can be explained by within subject and between trial variability. Muscle activation patterns were found to be similar in all muscles (ICC≤0.82). Similar patterns are supported by non-significant differences in mean direction of activation and muscle activation specificity. These results indicated that healthy older adults utilise different activation magnitudes for stabilising the knee while maintain similar muscle activation synergies in all muscles to younger adults.

Quadriceps muscle weakness is a condition that can result from a wide variety of causes, from diseases like polio and multiple sclerosis to injuries of the head and spine. Individuals with weakened quadriceps often have difficulty supplying the knee-extension moments required during common mobility tasks. Existing powered orthoses that provide an assistive knee-extension moment are large and heavy, with power supplies that generally last less than two hours. A new device that provides a knee-extension-assist moment was designed to aid an individual with quadriceps muscle weakness to stand up from a seated position, sit from a standing position, and walk up and down an inclined surface. The knee-extension-assist (KEA) was designed as a modular component to be incorporated into existing knee-ankle-foot-orthoses (KAFO). The KEA consists of three springs that are compressed, as the knee is flexed under bodyweight, by cables that wrap around a sheave at the knee. The KEA returns the stored energy from knee flexion as an extension moment during knee extension. During swing or other non-weight bearing activities, the device is disengaged from the KAFO by decoupling the sheave from the KAFO knee joint, allowing free knee joint motion. A prototype was built and mechanically tested to determine KEA behaviour during loading and extension and to ensure proper KEA function. For biomechanical evaluation, able-bodied subjects used the prototype KEA while performing sit-to-stand, stand-to-sit, ramp ascent, and ramp descent tasks. The KEA facilitated sitting and standing, providing an average of 53 % of the required extension moment for the two participants, which allowed one participant to reduce quadriceps usage by 38 % and the other to perform sit-to-stand in a slower and more controlled manner that was not possible without the KEA. KEA use during ramp gait caused an overall increase in quadriceps activation by 76 %, on average, with use. Future efforts will be made to modify the design to improve functionality, especially for ramp gait, and to reduce device size and weight.