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1
Schrader, Kate. "Knee Surgery: Total Knee Replacement or Partial Knee Replacement". University of Toledo Honors Theses / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=uthonors1305216135.
Testo completo
2
Zhang, Yin, e 張銀. "Validation of the new knee society knee scoring system for outcome assessment after total knew arthroplasty". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2013. http://hdl.handle.net/10722/193564.
Testo completoAbstract (sommario):
Introduction:
This retrospective comparative study was to define the validity and reliability of a translated, culturally adapted Chinese version questionnaire of the New Knee Society Knee Scoring System (NKSS).
This study is aim to investigate the validity and reliability of the translated Chinese version of the NKSS and assess its feasibility of measuring the scale on Chinese patients by performing its cross-cultural adaptation for patients after Total Knee Arthroplasty (TKA) in Hong Kong.
Methods:
A total of 104 knees from 64 Chinese patients performed TKA were included in the study using the translated, culturally adapted Chinese version of the NKSS. All Patients were operated on from October 2010 to May 2013 at Queen Mary Hospital. Patients who participated in this study have been clinically screened and established a set of including criteria. The outpatients were evaluated by completing the five questionnaires containing the NKSS, the Knee Society Clinical Rating System (KSS), Medial Outcomes Study 36+Item Short Form (SF-36), Bristol Knee Score and Oxford Knee Score.
Reliability was evaluated using the Split-half reliability, Chronbach's α coefficient and inter-item correlation. To assess validity, all patients filled in the same NKSS questionnaire, and previously validated Chinese version of the SF-36, Bristol Knee Score and Oxford Knee Score. The validity was determined with Content Validity and Contract Validity.
Results:
The NKSS showed ideal split-half reliability as evidenced by the high correlation coefficient (R>0.7, P<0.05). Chronbach's α coefficient for five major domains demographics, objective knee score, expectations, satisfaction and function was high (α>0.7. P<0.05). Also, the inter-item correlation was also excellent for all domains. For validity, the NKSS was found to have excellent correlation with Bristol Knee Score and Oxford Knee Score, good correlation with KSS and SF 36
Discussion:
The NKSS as a validated approach is adapted to the diverse health-related quality of lives and activities of contemporary patients with TKA. Orthopaedics surgeons are allowed to appreciate differences in the priorities of individual patients and the interplay among function, expectation, symptoms, and satisfaction after TKA using this assessment instrument.
Conclusion:
The results of this study show that the NKSS as a functional status questionnaire has been translated into Chinese without missing any psychometric properties of the original version. This culturally and linguistics adapted Chinese version of the NKSS outcome assessment has satisfactory internal consistency and good validity. It is an adequate and helpful instrument for the evaluation of Chinese speaking patients after TKA in clinical studies.published_or_final_version
Medical Sciences
Master
Master of Medical Sciences
3
Schmitt, Laura Clare. "Knee stabilization and medial knee osteoarthritis". Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file 0.80 Mb., 201 p, 2006. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:3220738.
Testo completo
4
Reynolds, Sarah. "Does Total Knee Arthroplasty Reproduce Natural Knee Mechanics". Thèse, Université d'Ottawa / University of Ottawa, 2013. http://hdl.handle.net/10393/24403.
Testo completoAbstract (sommario):
As the number of total knee arthroplasty (TKA) procedures increases annually, the patient demographic is shifting to include younger patients with higher expectations for post-operative function. The aim of this study was to compare movement patterns during activities of daily living among TKA patients and a healthy, age-matched group using 3D motion analysis. Specifically, this analysis looked at walking on level and inclined surfaces, as well as sitting up and down from a chair. It was predicted that (1) TKA patients would exhibit reduced knee extension moments at the operated limb and increased adduction moments at the contralateral limb during gait, (2) walking downhill would result in greater differences between TKA and control groups, compared to level walking, and (3) TKA participants would have greater flexion angles, moments and power values at the hip, compared to controls, during the sit-stand tasks. Seventeen participants (age=62±6 years, BMI=30±3 kg/m2, time after surgery=11±5 months) were recruited from the Ottawa Hospital, having undergone unilateral TKA by the same surgeon. An age-matched control group was composed of 17 individuals (age=63±8 years, BMI=27±4 kg/m2) who were recruited from the local community. Three dimensional (3D) biomechanical assessment was conducted with all participants performing five trials of walking on level and inclined surfaces, stair ascent and descent as well as sit-stand tasks. Results from this study were focused on gait and sit-stand transitions, showing that TKA participants exhibited altered gait patterns on both walking surfaces, with significantly smaller knee flexion angles and moments, as well as reduced peak power at the knee. The TKA group also experienced reduced knee extension moments; however, this was only significant for downhill walking. Consistent with our hypothesis, downhill walking resulted in greater discrepancies between the groups compared to level walking. Contrary to our third hypothesis, TKA participants exhibited significantly smaller peak hip flexion angles and moments during the sit-stand task, along with reduced hip abduction angles and knee abduction moments. The reduced knee flexion kinematics and kinetics observed during gait tasks, combined with the differences in frontal plane mechanics observed during the sit-stand task suggest that altered loading patterns persist six to twelve months after surgery. This may be a result of continued pre-operative movement patterns as well as the surgery itself, and should be kept in mind when developing rehabilitation programs for this patient population.
5
Lane, Judith. "Knee joint stiffness and function following total knee arthroplasty". Thesis, University of Edinburgh, 2010. http://hdl.handle.net/1842/4790.
Testo completoAbstract (sommario):
Introduction: Studies show that Total Knee Arthroplasty (TKA) is successful for the majority of patients however some continue to experience some functional limitations and anecdotal evidence indicates that stiffness is a common complaint. Some studies have suggested an association between stiffness and functional limitations however there has been no previous work which has attempted to objectively quantify knee joint stiffness following TKA. The purpose of this study was to pilot and evaluate a method for the quantitative evaluation in joint stiffness in replaced knees, OA knees and healthy controls and to explore whether there is an association between stiffness and functional limitations post-TKA surgery. Methods: The first part of the study created a biomechanical model of knee stiffness and built a system from which stiffness could be calculated. A torque transducer was used to measure the resistance as the knee was flexed and extended passively and an electrogoniometer concurrently measured the angular displacement. Stiffness was calculated from the slope of the line relating the passive resistive torque and displacement. The torque and joint angle at which stiffness was seen to increase greatly was also noted. The system was bench tested and found to be reliable and valid. Further tests on 6 volunteers found stiffness calculations to have acceptable intra-day reliability. The second part was conducted on three groups: those with end-stage knee OA (n = 8); those who were 1 year post-TKA (n = 15) and age matched healthy controls (n = 12). Knee range of motion was recorded and participants then completed the WOMAC, the SF-12 and a Visual Analogue Score for stiffness as well as indicating words to describe their stiffness. Four performance based tests – the Timed Up and Go (TUG), the stair ascent/descent, the 13m walk and a quadriceps strength test were also undertaken. Finally, passive stiffness at the affected knee was measured. Results: 100% of OA, 80% of TKA and 58% of controls reported some stiffness at the knee. The OA group reported significantly higher stiffness than the OA or TKA groups. There was no difference in self-reported stiffness between the TKA and control groups. Of the total number of words used to describe stiffness, 52% related to difficulty with movement, 35% were pain related and 13% related to sensations. No significantly differences were found between groups in the objective stiffness measures. Significant differences were found however in threshold flexion stiffness angles between groups. When this angle was normalised, differences between groups were not significant. No significant differences were found between groups in the threshold stiffness torque. Greater self-reported stiffness was found to be associated with worse self-reported function. A higher flexion stiffness threshold angle was associated with slower timed tests of function but also with better quadriceps muscle strength. Conclusions: The results support anecdotal reports that perceived stiffness is a common complaint following TKA but there was no evidence to show that patients with TKA have greater stiffness than a control group. There was however evidence to show that patients’ were unable to distinguish between sensations of stiffness and other factors such as pain. Self-perceived increased stiffness was associated with worse functional performance. Greater stiffness however was not necessarily negative. Stiffness increases earlier in flexion range were associated with better functional performance. These results suggest that an ideal threshold range for stiffness may exist; above which negative perceptions of the knee result in worse function but below which, knee laxity and instability may also result in worse function.
6
Garrett, Benjamin R. "Knee pain, swelling and stiffness after total knee replacement : a survey of South African knee surgeons". Master's thesis, University of Cape Town, 2011. http://hdl.handle.net/11427/2841.
Testo completo
7
Molloy, Martin-Patrick. "The biomechanics of the knee of total knee replacement golfers". Thesis, Ulster University, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.625503.
Testo completoAbstract (sommario):
Total knee arthroplasty (TKA) - the replacement of the articulating surfaces of the knee joint - is an increasingly used intervention for osteoarthritis. Younger, more active patients are undergoing TKA due to the clinical success of the implants. Surgeons must make recommendations on the suitability of post-surgery sporting activities; a balance must be struck between the health-promoting nature of the activity and the risk involved to the implant. Golf has been identified as a sport with a large number of participants that is recommended by the majority of knee surgeons. Despite golf being considered a low risk activity, there is limited scientific evidence that the loading applied to the knee-joint may be larger than assumed. Thus, the main aim of this thesis was to provide objective biomechanical data to contribute to our scientific knowledge base and to provide meaningful clinical data to enable medical practitioners to make informed decisions regarding the appropriateness of golf as an activity for post -TKA individuals. Three studies are presented in this thesis. The first investigated the suitability of a standard six-degrees-of-freedom (6DoF) marker model and tested the performance of an alternative model that included an 'optimised', modified cluster design placed on a site of low soft tissue artefact. Whilst statistically significant differences were identified between knee angles derived from each cluster design, the magnitude of the differences were small. Thus, both of the marker models were considered to provide knee-angle measurements that would be considered equivalent in a clinical setting.
8
Newman, Simon David Standen. "Improving outcomes in knee arthroplasty : the lateral unicompartmental knee replacement". Thesis, Imperial College London, 2016. http://hdl.handle.net/10044/1/39290.
Testo completoAbstract (sommario):
Total knee replacement (TKR) continues to increase in popularity, but satisfying patients who remain active for longer is a major challenge. Outcomes from TKR remain suboptimal, with as many as 20% gaining little benefit. An alternative approach to TKR is the use of partial or unicompartmental knee replacements (UKR). These are smaller and safer operations, but are arguably more difficult to perform and have been associated with a higher rate of revision surgery. Whilst a great deal is understood about medial UKR, relatively little is known about lateral UKR and this procedure forms the basis of this thesis. Outcomes of a lateral UKR implant, the Oxford Domed Lateral Partial Knee were assessed through upto 10 year follow-up of the largest independent series of this implant and demonstrated similar rates of revision and Oxford Knee Scores to previously published medial UKR series. Further assessment of the gait of patients with the same implant however failed to show a significant improvement over demographically matched patients with TKR. Accuracy of implant positioning is important for achieving optimal outcomes. One technology that may assist in delivering expert level skill is patient specific instrumentation (PSI). For the first time, the effect of changes in PSI guide design were explored, demonstrating the importance of achieving multiplanar bone contact. The use of PSI guides compared to traditional instruments was associated with superior femoral implant positioning and a trend for superior tibial implant positioning when used by inexperienced surgeons on a training course. The effect of tibial implant malpositioning on tibial strain was demonstrated using digital image correlation. Excessive posterior slope and tibial resection should be avoided to prevent higher tibial strains that may result in fracture. A pre-requisite for successful arthroplasty, including lateral UKR, is the establishment of osseomechanical integration. Enhanced osseomechanical integration may be better achieved with strontium-substituted bioactive glass (SrBG) than a hydroxyapatite (HA) coating as demonstrated in a lapine model. The data presented in this thesis demonstrates that lateral UKR is a challenging but effective operation, though further development is required to facilitate normal gait. Further improvements in function and outcomes may be achievable through the use of PSI and enhanced implant fixation with SrBG coatings.
9
McAlindon, Timothy Edward. "Knee joint failure". Thesis, University of Southampton, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.386627.
Testo completo
10
Petterson, Stephanie Christine. "Knee osteoarthritis and total knee arthroplasty quadriceps weakness, rehabilitation, and recovery /". Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file 1.02 Mb., 222 p, 2006. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:3205435.
Testo completo
11
Crenshaw, Jeremy. "Knee-joint loading variability during gait in subjects with knee osteoarthritis". Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 42 p, 2007. http://proquest.umi.com/pqdweb?did=1338917851&sid=5&Fmt=2&clientId=8331&RQT=309&VName=PQD.
Testo completo
12
Parekh, Sanjay M. "The risk of knee pain and knee osteoarthritis in professional footballers". Thesis, University of Nottingham, 2017. http://eprints.nottingham.ac.uk/43010/.
Testo completoAbstract (sommario):
Introduction: Knee osteoarthritis (KOA) is a common complex disorder. Although previously believed to be degenerative, KOA is in fact a regenerative condition, compensating against insults sustained at the joint. However, a failure of this compensatory repair process, especially in the presence of constitutional and local joint factors, increases the risk of KOA and inevitably leads to joint-failure (Dieppe and Lohmander, 2005, Arden and Nevitt, 2006, Sandell, 2012). Diagnosis of KOA may be made via clinical presentation, imaging, or using clinical algorithms, which may be a combination both in addition to biochemical diagnostic tests (Brandt et al., 2003). Knee pain (KP) is the most common symptom, and in the general population its prevalence is 25% (Peat et al., 2001a). Patients may also experience early morning stiffness of the joint and reduced function. Physician-observed signs include crepitus, restricted movement, and bony and soft tissue swellings (Abhishek and Doherty, 2013). Although considered the gold standard to diagnose KOA, plain film radiography is not without its limitations (Wick et al., 2012). Clinicians, however, favour radiography because it can easily discern two key features of the condition: joint space narrowing (JSN), a surrogate of cartilage loss, and the formation of osteophytes on the joint margin (Roemer et al., 2014). Assessment of radiographs is most commonly undertaken using Kellgren-Lawrence (KL) grade verbal descriptors (Altman et al., 1986a). The prevalence of radiographic KOA (RKOA) may be higher than KP, but there is a discordance between people reporting symptoms and those with structural change (RKOA) (Peat et al., 2001a, Bedson and Croft, 2008). A plethora of constitutional risk factors and joint-specific biomechanical factors increase the risk of KOA, including joint injury and occupation (Suri et al., 2012, Silverwood et al., 2015). One such occupation, which has a greater risk of injury are professional footballers (Drawer and Fuller, 2002) and knee injuries account for 17% of all footballing injuries (Ekstrand et al., 2011). Football is one of the most common team sports worldwide, with over 265 million people worldwide play the game (FIFA, 2007a), and of these, 110,000 are male professional footballers (FIFA, 2007b). Although perceived that that footballers are at great risk of long-term consequences such as KOA, due to their high risk of injury, the current evidence supporting this is limited (Kuijt et al., 2012, Tran et al., 2016). The previous studies observing KOA in footballers are difficult to generalise to the wider football population. This is for a number of reasons, including recruitment of inadequate sample, absence of inappropriate control groups, and differing case definitions, all resulting in a large variation in prevalence of KOA. Thus, there exists a need for a comprehensive study to determine the true prevalence and risk of KOA in retired professional footballers compared to the general population. Aims: (1) To determine the prevalence and risk of KOA (measured as KP, RKOA and requirement for total knee replacement (TKR)) in retired professional footballers compared to the general population; (2) To determine the specific factors (constitutional, biomechanical and football-specific) that are associated with an increased risk of each of these outcomes (KP, RKOA and TKR) within footballers. Methods: The Nottingham University Hospitals NHS Trust and the Nottingham Research Ethics Committee (Refs 14/EM/0045; 14/EM/0015) approved this study, which was registered on the clinicaltrials.gov portal (NCT02098044; NCT02098070). This study design involved carrying out two cross-sectional studies. The Football Study involved distributing 4775 postal questionnaire surveys to retired professional footballers via multiple sources, including football clubs, their former players’ associations and the Professional Footballers Association (PFA). The Knee Pain and Related Health in the Community Study (KPIC) involved distributing 40,500 postal questionnaires, via 12 general practice surgeries, to both men and women in the East Midlands general population. However, only men formed the control group for this study. The inclusion criteria for both the footballers and control participants was the same: men aged 40 and older. The questionnaires, developed based on previously literature, were similar to capture detailed information about KP, undergoing a TKR and putative risk factors for KOA, including knee injuries, surgery and alignment. The questionnaires also gathered information regarding demographics, medical and occupational history, general health and current medication. Following this, footballers and controls who consented had radiographic assessments of both their knees, including weight-bearing semi-flexed posterior-anterior (PA) view using the Rosen template (Rosenberg et al., 1988) and a seated 30° flexion skyline view. A single observer (GSF) scored all the radiographs as a single mixed batch using HIPAX Dicom software. In addition to the KL grades, the Nottingham Line Drawing Atlas (NLDA) was used (Nagaosa et al., 2000) (Wilkinson et al., 2005), which scored composite joint space narrowing (JSN), composite osteophyte, and a combined global score for each knee. Primary outcomes observed were current KP, RKOA (measured using the NLDA) and TKR. Secondary outcomes observed were ever having KP (chronic), physician-diagnosed KOA, RKOA (measured using KL grades) and radiographic CC. Power calculations determined the sample size for the questionnaire survey and the radiographic survey. Categorical variables presented as frequency and percent and compared using a chi-squared test. Continuous variables presented as mean and standard deviation and compared using a t-test. The risk of KOA (measured for each outcome independently) in footballers compared to the controls was determined using a generalised linear model (GLM) with a Poisson distribution, and adjusted for known risk factors (including age, body mass index (BMI) and previous knee injury). The specific risk factors within footballers associated with outcomes of KOA (namely KP, RKOA and TKR) were determined using multivariate logistic regression. Results: 1207 footballers (response rate of 25.3%) and 4085 control men responded to the Football and KPIC studies respectively, which was far lower than studies previously conducted in both populations. Following this, 470 footballers and 500 men consented to undergoing radiographic assessment of their knees. For participants who returned the questionnaire (footballers and controls), characteristics were compared between those who underwent a knee radiograph and those who did not. Age and sustaining a knee injury were the main factors significantly difference in both. Footballers were significantly older (3.9 years) than the controls, but were gender-matched (males-only) and had a similar BMI. Footballers had a significantly greater number of injuries (64.5% v. 23.3%) compared to the controls. They also had significantly more body pain (74.7% v. 69.8%) and therefore took more pain-relief medication (61.9% v. 28.5%). However, footballers suffered from far fewer comorbidities compared to the controls (29.4% v. 45.7%). Footballers had a far greater prevalence of both primary and secondary outcomes. The prevalence of KP was almost twice as great in footballers (52.2%) compared to the controls (26.9%) and this increased prevalence was regardless of age. The peak prevalence of KP also occurred at least ten years earlier in footballers compared to the controls. Although the prevalence of physician-diagnosed KOA was much lower than the prevalence of KP in footballers (28.3%), it was more than double that of the controls (12.2%). Additionally, footballers (11.1%) had almost three times greater prevalence of TKR compared to the controls. Risk factors significantly associated with footballers who had undergone a TKR, included age [OR 1.09, 95% CI 1.07-1.11], being obese [OR 1.77, 95% CI 1.00-3.12] and having gout [OR 3.11, 95% CI 1.96-4.70]. Sustaining a significant knee injury [OR 3.11, 95% CI 1.94-4.99] and receiving an intra-articular knee injection [OR 2.56, 95% CI 1.76-3.73] were also significant risk factors for footballers who underwent a TKR. However, those footballers with a longer duration of playing the game [OR 0.95, 95% CI 0.92-0.98] had a reduced risk of TKR.Conclusion: These findings show footballers have a greater risk of KOA compared to the general population, reporting up to three times higher prevalence of various outcomes (KP, RKOA, physician-diagnosed KOA and TKR). The age-prevalence of all outcomes of KOA, are greater in footballers compared to the controls. The high prevalence of injuries significantly account the risk of KOA in footballers compared to the controls (even following adjustment of other risk factors). Within footballers, knee injuries, together with subsequent investigations (specifically exploratory and interventional arthroscopy) and management (specifically intra-articular knee injections), were strongly associated with risk of KOA (KP, RKOA and TKR independently). Football’s governing bodies need to set out and implement strategies to reduce or even prevent the risk of serious injury (thus reducing the risk of subsequent investigation). This will reduce the risk of long-term consequences, such as KOA. However, whether the Industrial Injuries Advisory Council considers the risk of KOA in footballers an industrial compensable disease remains a question.
13
Perrin, Joshua David. "The Influence of Static Stretching of Knee Flexors on Knee Biomechanics". Wright State University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=wright1535055379518429.
Testo completo
14
Kosiuk, Monica. "Quantitative analysis of functional knee appliances in controlling anterior cruciate ligament deficient knees". Thesis, McGill University, 1990. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=60013.
Testo completoAbstract (sommario):
The purpose of this investigation was to evaluate and compare the efficacy of three functional knee braces in stabilizing anterior cruciate ligament (ACL) deficient knees. The subject sample consisted of eighteen males and females with a unilateral ACL deficiency.The criterion variables consisted of the ability of each brace in controlling internal rotation and knee extension during active movement and knee extension during a high velocity activity (dynamic task). Total displacement of the knee brace during a running test was also evaluated.
The results of this study demonstrated significant differences between the efficacy of the three braces for control of knee extension during active movement, knee extension during a dynamic task and brace migration during a running task. There was no significant difference between the efficacy of the three braces in controlling internal rotation during active movement.
15
Gardinier, Joseph D. "Evaluation of an EMG-driven model and its ability to estimate joint moments at the knee". Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 80 p, 2007. http://proquest.umi.com/pqdweb?did=1251904611&sid=2&Fmt=2&clientId=8331&RQT=309&VName=PQD.
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16
Morris, Richard William. "Comparative evaluation of outcome of knee replacement operations using alternative knee prostheses". Thesis, King's College London (University of London), 1993. https://kclpure.kcl.ac.uk/portal/en/theses/comparative-evaluation-of-outcome-of-knee-replacement-operations-using-alternative-knee-prostheses(00819d6c-a443-4cf3-b2f6-9276f24536e6).html.
Testo completo
17
Mangudi, Varadarajan Kartik 1981. "In vivo knee biomechanics and implications for total knee arthroplasty implant design". Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/58287.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2010.Cataloged from PDF version of thesis.
Includes bibliographical references.
The overall objective of this thesis was to determine the limitations of contemporary Total Knee Arthroplasty (TKA) and to identify areas for future improvements. In line with this objective, the first goal was to quantify the ability of current TKA systems to restore normal knee kinematics and anatomy. Recently, proposals for gender specific TKA have generated much controversy, with little scientific information being available to support or refute the need for such implants. Therefore, a second goal of this thesis was to investigate similarities and differences between male and female knee kinematics and anatomy, to determine if significant benefits can be obtained by incorporating gender specific variations into TKA designs. With regards to the first objective, significant differences were noted between the trochlear groove geometry of standard TKA implant and the normal knee, which could lead to non-physiologic patellar tracking post-TKA. Additionally, following TKA the knee joints were overstuffed in flexion, which may in part be responsible for limited post-operative range of knee flexion. Finally, standard TKA did not restore the kinematics of osteoarthritic knees towards normal, and normal kinematics patterns such as posterior femoral translation and internal tibial rotation were substantially reduced after TKA. With regards to gender differences, majority of the tibiofemoral and all patellofemoral kinematic parameters were similar between male and female knees. However, females had more externally rotated tibia in early flexion and greater range of tibial rotation. This difference was also associated with a more medially oriented patellar tendon in the coronal plane and more externally twisted patellar tendon in the transverse plane, in females. Regarding knee anatomy, the only gender difference was the narrower width of the femoral sulcus and lateral femoral condyle in females. Thus, compared to differences between current TKA and the average normal knee, these gender differences were relatively subtle. Therefore, the focus for future TKA designs should be restoring the average normal knee biomechanics. Additionally, a greater range of implant sizes may be desirable to accommodate morphological variations in the widths of male and female knees.
by Kartik Mangudi Varadaraian.
Ph.D.
18
Van, den Heever David Jacobus. "Development of patient-specific knee joint prostheses for unicompartmental knee replacement (UKR)". Thesis, Stellenbosch : Stellenbosch University, 2011. http://hdl.handle.net/10019.1/17942.
Testo completoAbstract (sommario):
Thesis (PhD)--Stellenbosch University, 2011.ENGLISH ABSTRACT: The knee is the largest, most complicated and incongruent joint in the human body. It sustains very high forces and is susceptible to injury and disease. Osteoarthritis is a common disease prevalent among the elderly and causes softening or degradation of the cartilage and subcondral bone in the joint, which leads to a loss of function and pain. This problem can be alleviated through a surgical intervention commonly termed a “knee replacement”. The aim of a knee replacement procedure is to relieve pain and restore normal function. Ideally, the knee replacement prosthesis should have an articulating geometry similar to that of the patient’s healthy knee, and must allow for normal motion. Unfortunately, this is often problematic since knee prostheses are supplied in standard sizes from a variety of manufacturers and each one has a slightly different design. Furthermore, commercial prostheses are not always able to restore the complex geometry of an individual patient’s original articulating surfaces. This dissertation shows that there is a significant variation between knee geometries, regardless of gender and race. This research aims to resolve the problem in two parts: Firstly by presenting a method for preoperatively selecting the optimal knee prosthesis type and size for a specific patient, and secondly by presenting a design procedure for designing and manufacturing patient-specific unicompartmental knee replacements. The design procedure uses mathematical modelling and an artificial neural network to estimate the original and healthy articulating surfaces of a patient’s knee. The models are combined with medical images from the patient to create a knee prosthesis that is patient-specific. These patient-specific implants are then compared to conventional implants with respect to contact stresses and kinematics. The dissertation concludes that patient-specific implants can have characteristics that are comparable to or better than conventional prostheses. The unique design methodology presented in this dissertation introduces a significant advancement in knee replacement technology, with the potential to dramatically improve clinical outcomes of knee replacement surgery.
AFRIKAANSE OPSOMMING: Die knie is die grootste, mees komplekse en mees ongelyksoortige gewrig in die liggaam. Osteoarthritis is ’n siekte wat algemeen by bejaardes voorkom en die versagting of agteruitgang van die kraakbeen en subchondrale bene in die gewrig tot gevolg het, wat tot ’n verlies van funksionering en pyn lei. Hierdie probleem kan verlig word deur ’n chirurgiese ingryping wat algemeen as ’n “knievervanging” bekend staan. Die doel van ’n knievervangingsprosedure is om pyn te verlig en normale funksionering te herstel. Ideaal gesproke behoort die knievervangingsprostese ’n gewrigsgeometrie te hê wat soortgelyk aan die pasiënt se gesonde knie is, en normale beweging moontlik maak. Ongelukkig is dit dikwels problematies aangesien knieprosteses in standaardgroottes en deur ’n verskeidenheid vervaardigers verskaf word, wat elkeen se ontwerp effens anders maak. Verder kan kommersiële prosteses nie altyd die komplekse geometrie van ’n individuele pasiënt se oorspronklike gewrigsoppervlakke vervang nie. Hierdie proefskrif wys dat daar ’n betekenisvolle variasie tussen knieafmetings is, afgesien van geslag en ras. Hierdie navorsing is daarop gemik om die problem op tweërlei wyse te benader: Eerstens deur ’n metode aan te bied om die optimal knieprostesetipe en -grootte vir ’n spesifieke pasiënt voor die operasie uit te soek, en tweedens om ’n ontwerpprosedure aan te bied vir die ontwerp en vervaardiging van pasiëntspesifieke unikompartementele knievervangings. Die ontwerpprosedure gebruik wiskundige modellering en ’n kunsmatige neurale netwerk om die oorspronklike en gesonde gewrigsoppervlakke van ’n pasiënt se knie te bepaal. Die modelle word met mediese beelde van die pasiënt gekombineer om ’n knieprostese te skep wat pasiëntspesifiek is. Hierdie pasiëntspesifieke inplantings word dan met konvensionele inplantings vergelyk wat kontakstres en kinematika betref. Daar word tot die slotsom gekom dat die pasiëntspesifieke inplantings oor eienskappe kan beskik wat vergelykbaar is met of selfs beter is as dié van konvensionele prosteses. Die unieke ontwerpmetodologie wat in hierdie proefskrif aangebied word, stel beduidende vordering in knievervangingstegnologie bekend, met die potensiaal om die kliniese uitkomste van knievervangingsoperasies dramaties te verbeter.
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Nazbar, Khalid, e I. M. Shalimov. "The osteotomy of the knee deformation after gonarthrosis (arthrosis of the knee)". Thesis, Sumy State University, 2015. http://essuir.sumdu.edu.ua/handle/123456789/41308.
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Campbell, Neil. "Design of a knee simulator for the testing of total knee prostheses". Master's thesis, University of Cape Town, 2008. http://hdl.handle.net/11427/3228.
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Tian, Feng. "A superelastic variable stiffness knee actuator for a knee-ankle-foot orthosis". University of Toledo / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1449578210.
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Li, Jialong. "Optimisation Of Ligament Balancing And Knee Joint Kinematics In Total Knee Arthroplasty". Thesis, The University of Sydney, 2023. https://hdl.handle.net/2123/29945.
Testo completoAbstract (sommario):
Total knee arthroplasty (TKA) is a successful surgery for the clinical management of OA. The procedure has been demonstrated to alleviate pain due to degeneration of articulating surface of the joint, restore function and mobility and increase the quality of life for recipients. Well-balanced post-operative knee joints are often based on subjective ‘feel’ of experienced surgeons rather than quantifiable references. Most alignment strategies are still referencing the bone despite the complexity in anatomical variations and presence of deformity. This dissertation aims to investigate the contribution of soft tissue structures in the pre-operative decision-making process to explain a proportion of unsatisfied patients.
Identifying the ‘goldilocks’ zone which allows for the perfect restoration of motion characteristics following implantation remains elusive. Addressing the final 20% of dissatisfaction is complex and yet to be solved in today’s technologically advanced clinical landscape. This dissertation suggest accuracy of many surgical delivery technologies in achieving a prescribed alignment philosophy can be inappropriate and irrelevant to the random nature of soft tissue profile for any given patient. Current assessment methods of soft tissue structure can be highly subjective to the surgeon and can often produce an input that is unreliable in identifying the true needs of the knee joint. Soft tissue, which contributes just as much as the boney anatomy to the kinematic behaviour of the patient, is far more complex and largely unmeasured. In doing so, this dissertation demonstrated the current alignment philosophies active places the components beyond the capabilities of the ligament despite many claiming to be soft tissue sparing and catering. In the pursuit of maximizing patient outcomes and post-operative satisfaction, surgeons should carefully consider varied resection of the bone based on the soft tissue on a patient specific basis.
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Mahler, Sebastian. "Compliant pediatric prosthetic knee". [Tampa, Fla.] : University of South Florida, 2007. http://purl.fcla.edu/usf/dc/et/SFE0002278.
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Krehbiel, Beth Ann. "Narratives of Wounded Knee". Kansas State University, 2016. http://hdl.handle.net/2097/32870.
Testo completoAbstract (sommario):
Master of Landscape ArchitectureDepartment of Landscape Architecture/Regional and Community Planning
Laurence A. Clement
Research suggests that Native Americans, Chicanos, and African Americans are groups underrepresented in the North American memorial landscape. The fluid nature of a group and individual’s identity (and the memory that shapes it) contributes to the underrepresentation in commemoration and memorials. As communities and the associated identities continue to blend and overlap moments of positive cultural exchange can take place, but at times the outcomes are in the realm of contention and conflict. The collaborative nature of landscape architecture together with the profession’s ability to understand and interpret complex systems and narratives can fully engage and bring form to the morally imaginative, creative act of peacebuilding. The concept of shifting and variant meaning led to this study that considered the question- How might memorials be designed as reconciliatory agents in cultural landscapes with conflicting histories? This study engaged the concept of memory and identity with Oglala Lakota, on the Pine Ridge Reservation, regarding the tragedy of Wounded Knee, through adapted ethnographic approaches in interviewing, site visits, extensive literature review, mapping and design inquiry. The design inquiry responds to social, economic, and ecological narratives to inform the design of the reconciliatory-minded memorial. The initial premise of the project was situated in the understanding that events with contested meaning are difficult to memorialize because there are so many differing voices; irreconcilable in the built form. While that is true in some contexts, initial findings suggests these groups are underrepresented because it is difficult to memorialize that which is a contemporary social justice or inter-demographic issue. In light of this and further research, the author believes that memorials seeking to honor demographics or events that directly affect contemporary groups might be contextually more appropriate, and act as mediators, if they focus forward rather than solely and solemnly reflect the past. Conceptual sketches conclude this study, offering possibilities for design expression, which might be realized with community participation.
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Clarke, Jon V. "The non-invasive measurement of knee kinematics in normal, osteoarthritic and prosthetic knees". Thesis, University of Strathclyde, 2012. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=17190.
Testo completoAbstract (sommario):
Total knee arthroplasty (TKA) is the most widely performed intervention for endstage osteoarthritis (OA) but in spite of limitations in surgical techniques, alignment measurements and clinical outcomes, the expectations of an active, aging population continue to increase. The aim of this thesis was to develop and validate a noninvasive kinematic assessment tool to improve the measurement of knee alignment and ligament laxity. An intra-operative infrared tracking system was adapted for non-invasive use through the development of external mountings that enabled alignment measurements to be made supine, standing and following manual collateral stress. Coronal and sagittal plane mechanical femorotibial (MFT) angle measurement was validated to a precision of approximately ±1° by comparison to a custom made leg model, a flexible electrogoniometer and through repeatability measurements on 30 asymptomatic volunteers. Assessment of coronal laxity was quantified and standardised by controlling lever arm, applied manual load and knee flexion angle. Thirty one patients with end-stage OA were assessed before, during and six weeks following TKA and comparisons were made between invasive and non-invasive MFT angles and between supine and standing conditions. For osteoarthritic knees, varus and valgus angular displacements were greater intraoperatively in comparison to pre-operative non-invasive measurements, whereas invasive and non-invasive stress angles for prosthetic knees showed less variation. From supine to bi-pedal stance, MFT angles most frequently changed to relative varus and extension for all knee types suggesting that soft tissue restraints may be more important than rigid bony or prosthetic architecture for controlling this weightbearing alignment change. The development of a non-invasive infrared (IR) system enabled knee alignment to be quantified as a dynamic parameter in comparison to current static assessment techniques such as radiographs. The generation of subject-specific kinematic profiles could help with the surgical planning and post-operative follow-up of patients undergoing alignment dependent procedures such as TKA.
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Bytyqi, Dafina. "Gait kinematic analysis of the osteoarthritic knee : pre- and post- total knee arthroplasty". Thesis, Lyon 1, 2015. http://www.theses.fr/2015LYO10020/document.
Testo completoAbstract (sommario):
Le but de cette thèse était d'étudier, in vivo, la cinématique en 3D du genou lors de la marche sur des patients souffrant d'arthrose du genou et de quantifier l'apport de l'arthroplastie totale du genou (PTG) sur la restauration d'une cinématique normale. Trente patients et un groupe de contrôle composé de 12 participants du même âge ont été inclus dans la première étude. Sur ces 30 patients, nous avons obtenu des évaluations de suivi après l'arthroplastie totale du genou sur 20 patients, avec un délai moyen de 11 mois. L'analyse cinématique tridimensionnelle du genou a été réalisée en utilisant le système KneeKGTM. Cette analyse de la marche a révélé que la cinématique de genou avec arthrose médiale diffère de la cinématique du genou sain. Le groupe avec arthrose du genou montrait une stratégie de raidissement de la marche en présentant une réduction de mouvement non seulement dans le plan sagittal, mais aussi dans le plan axial. Après PTG, les patients avaient de meilleurs paramètres cliniques, spatio-temporels et cinématiques. Malgré les améliorations, la cinématique du genou lors de la marche dans le groupe PTG différaient de celle du groupe contrôlePatients with knee osteoarthritis tend to modify spatial and temporal parameters during walking to reduce the pain. There are common gait features which are consistently shown to be significantly linked to osteoarthritis severity such as knee adduction moment, knee flexion angle, stiffness and walking speed. Total knee arthroplasty (TKA) is considered the gold standard treatment for end-stage knee osteoarthritis. Nearly a million of total knee prosthesis are implanted worldwide each year. However, reduced physical function of the knee is partly, but apparently not fully, remedied by surgery. The purpose of this thesis was to investigate the in vivo, three dimensional knee kinematics during gait at the patients with knee osteoarthritis and the influence of total knee arthroplasty on restoration of normal kinematics. Weight bearing kinematics in medial OA knees differ from normal knee kinematics. Knee OA group showed an altered “screw-home” mechanism by decreased excursion in sagittal and axial tibial rotation and a posterior translation of the tibia. Following TKA, patients had better clinical, spatiotemporal and kinametic parameters. They walked longer, faster and with a better range of motion. Despite improvements, the knee kinematics during gait in TKA group differed from healthy control group. They had a lower extension, lower range of axial rotation and an increased tibial posterior translation. Future research should be focused on comparing different designs of prosthesis pre- and post operatively in a longer follow-up delay
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Al-Sobayel, Hana I. "Construction and validation of the Saudi Knee Function Scale, a knee osteoarthritis index". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq22264.pdf.
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Goulston, Lyndsey. "The epidemiology and interaction of knee alignment and body mass on knee osteoarthritis". Thesis, University of Southampton, 2015. https://eprints.soton.ac.uk/397326/.
Testo completoAbstract (sommario):
The growing prevalence of knee osteoarthritis (KOA) is fuelled by the rising obesity epidemic and an ageing population. The lack of a KOA cure drives the need to identify prevention strategies with alternative treatments to surgery a priority. This requires careful investigation of risk factors and their interaction. Knee mal-alignment and excess body mass are KOA risk factors but their combined effect is less understood. These five studies examine knee alignment and body mass as separate risk factors, describing their natural history and their association with prevalence and incidence of symptomatic radiographic knee osteoarthritis (SRKOA), radiographic knee osteoarthritis (RKOA) and knee pain outcomes in a long-standing female cohort. The cross-sectional interaction of these risk factors and outcomes is examined. One-point (1P) versus two-point (2P) anatomic axis (AA) knee alignment measurements, and body mass index (BMI) versus waist circumference (WC) measurements are also compared. Differences between 1P and 2P measurements indicate method specific alignment categories are required. Improvements are identified in AA angle measurement that require further validation to establish a gold standard AA alignment method. Changes in AA alignment over 10 years were small, but limited by identification of rotated knees. Over 19 years the tripling amount of obese women, was associated with increased prevalence and incidence of SKROA, RKOA and knee pain. WC measurement offers no advantage over BMI in predicting SRKOA, but it could be substituted where height or weight measurement is difficult. Results suggest a cross-sectional interaction between BMI and alignment with SRKOA and RKOA but not with knee pain, indicating that it may be driven by structure. This is important for targeting timely treatment of these risk factors. This new knowledge should assist in identification of individuals who would benefit from early intervention and treatment, to reduce pain, suffering and high future costs of KOA.
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Hutter, Erin E. "The Effect of Surgical Technique During Total Knee Arthroplasty on Knee Joint Stability". The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1384641986.
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Ghosh, Kanishka Milton. "The effects of total knee replacement on the extensor retinaculum of the knee". Thesis, Imperial College London, 2009. http://hdl.handle.net/10044/1/5293.
Testo completoAbstract (sommario):
Introduction: Patellofemoral dysfunction following total knee replacement (TKR) is significant. Due to the intimate relationship of the femoral component and patella, aspects of knee arthroplasty such as femoral component malrotation and patellofemoral overstuff have been sited as predisposing factors to such complications. The principal structures of the extensor retinaculum act as a checkrein for the patella as it tracks over the femur. Little biomechanical information is available on the behaviour of these structures, or the effects of TKR on them. Aim: The aim of this thesis was to measure retinacular behaviour in the normal knee and following TKR. We hypothesise that TKR will cause significant elongation of the retinacula and this would be further deranged with the addition of femoral component malrotation and patellofemoral overstuff. Methods: Retinacular length changes were measured by threading fine sutures along the retinacula and attaching these to displacement transducers. The intact knee was flexed-extended on a custom built rig, while the quadriceps were tensed. Measurements were repeated post-TKR (Genesis II CR, Smith & Nephew Co.), following internal/external rotation of the femoral component 5° and finally altering the resurfaced patellar thickness by 2mm increments. Results: The medial patellofemoral ligament (MPFL) was close to isometric, whereas the lateral retinaculum slackened significantly with knee extension. TKR did not cause statistically significant elongation of the retinacula. Internal rotation of the femoral component resulted in the MPFL slackening whereas external rotation resulted in the MPFL tightening as the knee extended. The lateral retinaculum showed no significant differences. Overstuffing the patellofemoral joint caused significant stretching of the MPFL at all angles of knee flexion, but very little change in the lateral retinaculum. Conclusion: This work has shown a correctly positioned TKR does not cause significant retinacular length changes sufficient to affect knee function. It has shown that small changes in femoral component rotation and patellofemoral overstuff of 4mm cause significant changes, particularly in the medial structures and not the lateral structures, contrary to current understanding. This work has described for the first time how the lateral retinaculum’s mobile attachments allow its principal fibres to move anteriorly and posteriorly with the patella, taking up any slack/tension produced by abnormal patellar shift/tilt. This work provides important insight into the contribution of the retinacula to patellofemoral biomechanics after knee replacements and may help in developing a more soft tissue friendly knee prosthesis.
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Khoja, Latif. "Hip and knee frontal plane biomechanics in people with medial compartment knee osteoarthritis". Thesis, Kingston, Ont. : [s.n.], 2008. http://hdl.handle.net/1974/1054.
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Mentink, Michael Johannes Antonius. "Measurement of bearing load in unicompartmental knee arthroplasty using an instrumented knee bearing". Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:65a90ea6-77b6-49f2-9d8f-ecc4780dff81.
Testo completoAbstract (sommario):
The aim of this thesis was to investigate how to construct a system to measure load in a mobile unicompartmental knee replacement (UKR) bearing. In vivo loads have been measured in a total knee replacement (TKR), but with TKR the kinematics are different from those of the normal knee, whereas they are close to normal in a mobile UKR, so the loads measured by an instrumented UKR would be more representative of the normal knee. On the principle of measuring compression of an object under load, the load may be estimated. Compression measurement using a capacitive sensor was the optimal solution to measure load, based on life expectancy of the sensor and bearing integrity. A capacitive sensor within a polyethylene (UHMWPE) bearing has not been used before. The visco-elastic and temperature dependent properties of UHMWPE were determined with experiments. UHMWPE had an approximately linear response after ten minutes of applying a constant load. A temperature sensor should be used in vivo to compensate for temperature effects acting on the elastic modulus of UHMWPE. Finite element modelling demonstrated that positioning the sensor under the centre of the bearing concavity resulted in the largest capacitive change. The influence of various dimensional parameters on sensor output was simulated, and the conclusion was that the sensor only needs to be calibrated once. An electronic module inserted into a bearing had less than 5 % influence on bearing compression. Capacitive sensors were made from polyimide, using standard production methods, and embedded within a UKR bearing using the standard compression moulding process. The embedded sensor had a second order low pass frequency response, with a corner frequency of 9 Hz, twice the frequency required for typical functional loading such as gait. Physiological load signals, gait and step up/down, were applied to the bearing. The capacitance to load response was approximately linear. Load was estimated using a linear method and a dynamic method. The linear method performed best, with an accuracy of force estimation better than 90 %. In vitro tests were performed using a commercially available transceiver, two stan- dard antennas and a custom antenna, designed to be incorporated in the bearing. Wireless communication between an implanted custom antenna and an external an- tenna was shown to be feasible. Experiments were also performed that demonstrate that inductive powering of the bearing was feasible. In addition to load measurement, a proposal for dynamic measurement of the orien- tation angles of both the tibia and the femur was made. Power and volume calculations showed that it is possible to place an electronic module within the bearing. This thesis has not only demonstrated that it is feasible to make an instrumented bearing for UKR but has also provided a basic design for manufacturing.
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黃若虹 e Yeuk-hung Wong. "Kinematic analysis of rotation pattern of ACL deficient knee, ACL reconstructed knee and normal knee during single leg hop and pivotshift test". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2000. http://hub.hku.hk/bib/B31225378.
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Colvin, Matthew. "Quadriceps strength prediction equations in individuals with ligamentous injuries, meniscal injuries and / a thesis submitted to Auckland University of Technology in partial fulfilment of the requirements for the degree of Master of Health Science, School of Physiotherapy, 2007". Click here to access this resource online, 2007. http://hdl.handle.net/10292/379.
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Scarvell, Jennie. "Kinematics and degenerative change in ligament-injured knees". Connect to full text, 2004. http://hdl.handle.net/2123/4139.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--University of Sydney, 2004.Title from title screen (viewed Apr. 6, 2009) Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy to the School of Physiotherapy, Faculty of Health Sciences. Includes bibliography. Also available in print form.
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Wong, Yeuk-hung. "Kinematic analysis of rotation pattern of ACL deficient knee, ACL reconstructed knee and normal knee during single leg hop and pivot shift test /". Hong Kong : University of Hong Kong, 2000. http://sunzi.lib.hku.hk:8888/cgi-bin/hkuto%5Ftoc%5Fpdf?B23373258.
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Murray, Amanda Megan. "The Effects of High-Velocity Power Training on Knee Joint Mechanics in Knee Osteoarthritis". University of Toledo / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1404391903.
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Ewing, Joseph Allan Ewing. "The Effect of Patient-Specific Ligament Properties on Knee Mechanics Following Total Knee Arthroplasty". The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1461167761.
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Most, Ephrat 1970. "The biomechanics of knees at high flexion angles before and after Total Knee Arthroplasty". Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/17946.
Testo completoAbstract (sommario):
Thesis (Sc. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2004.Includes bibliographical references (leaves 215-234).
Total Knee Arthroplasty (TKA) was initially developed to alleviate pain in the case of severe arthritis of the knee. Restoration of knee motion has been an on going issue for the last decade. Contemporary TKAs appear to provide good knee function in the range of zero to 120⁰ of flexion for most patients. However, many patients rarely can flex tier knees beyond 120⁰ after TKA. Limited information is available regarding the biomechanics of the knee beyond 120⁰ of flexion. Little is known about the biomechanical function of the posterior cruciate ligament in cruciate retaining TKA designs and the interaction of the cam-spine mechanism in posterior-stabilized TKA designs at flexion angles greater than 120⁰. The role of soft tissue constraint at high flexion angles has not yet been explored. The objective of this work was to investigate the biomechanics of the knee at high flexion angles before and after TKA. An in vitro experimental robotic set-up was used to measure six degrees-of-freedom kinematics and soft tissue kinetics of the intact knee. Contemporary TKA designs were then tested on the same specimen using this system to examine the limitations of currently available components to achieve high knee flexion. Both passive and muscle load kinematics were examined. Femoral translation and tibial rotation of the reconstructed knees were compared with that of the intact knees from full extension to 150⁰ of flexion. The study showed that in the intact knee, the amount of posterior femoral translation increased with increasing flexion angles on the passive path and under simulated muscle loads. Similar trend was noted for all TKAs. Yet, after any TKA, the knee exhibited a reduction in posterior femoral translation relative to the intact knee. The
(cont.) posterior cruciate ligament in all knees carried lower load at high flexion as compared to the peak load it carried at mid knee flexion. The engagement of the femoral cam with the polyethylene spine in a posterior-stabilized TKA was correlated with an increasing posterior femoral translation. The function of the menisci was not simulated by any of the TKAs. In all knees, the compression of the posterior soft tissue at high knee flexion was correlated with an increase of posterior femoral translation. It is proposed that posterior femoral translation and internal tibial rotation ate high knee flexion are necessary but not sufficient features in achieving high knee flexion. Factors such as posterior soft tissue compression and contact mechanics should be considered.
by Ephrat Most.
Sc.D.
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Homminga, George Nicolaas. "Perichondrial arthroplasty of the knee". Maastricht : Maastricht : Datawyse ; University Library, Maastricht University [Host], 1989. http://arno.unimaas.nl/show.cgi?fid=5533.
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Veldhuizen, Jan Willem. "Knee immobilization techniques and evaluation /". Maastricht : Maastricht : Universitaire Pers Maastricht ; University Library, Maastricht University [Host], 1995. http://arno.unimaas.nl/show.cgi?fid=7935.
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Grimshaw, P. N. "Quantitative assessment of knee instability". Thesis, University of Salford, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234593.
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Burton, Andrew Peter. "Wear of unicompartmental knee replacements". Thesis, University of Leeds, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.427771.
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Dandy, David James. "Arthroscopic surgery of the knee". Thesis, University of Cambridge, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.240270.
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Liddle, Alexander David. "Failure of unicompartmental knee replacement". Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:c5bd883f-7c6f-42fe-9231-68609acaf234.
Testo completoAbstract (sommario):
Unicompartmental knee replacement (UKR) is the principal alternative to total knee replacement (TKR) in the treatment of end-stage knee osteoarthritis. It involves less tissue resection, resulting in lower rates of morbidity and faster recoveries compared to TKR. However, UKR has a significantly higher revision rate compared to TKR. As a result, whilst over a third of patients are eligible for UKR, only around 8% receive it. A comprehensive comparison of matched patients undergoing TKR and UKR was undertaken using a large dataset from the National Joint Registry for England and Wales (NJR). Failure rates (revision, reoperation, complications and mortality), length of stay and patient-reported outcomes (PROMs) were studied. Whilst patients undergoing TKR had lower reoperation and revision rates, they had higher rates of morbidity and mortality, longer hospital stays, and inferior PROMs compared to UKR. The main reason for revision in UKR was loosening. In view of the high revision rate in UKR, NJR data was studied to identify modifiable risk factors for failure in UKR. Important patient factors were identified including age, gender and pre-operative function. Surgeons with a higher UKR caseload had significantly lower revision rates and superior patient-reported outcomes. Increasing usage (offering UKR to a greater proportion of knee replacement patients) appears to be a viable method of increasing caseload and therefore of improving results. Surgeons with optimal usage (around 50% of patients, using appropriate implants) achieved revision/reoperation rates similar to matched patients undergoing TKR. Two clinical studies were conducted to establish whether the use of cementless fixation would improve fixation and reduce the revision rate of UKR. Cementless UKR was demonstrated to be safe and reliable, with PROMs similar or superior to those demonstrated in cemented UKR. Patients with suboptimal cementless fixation were examined and pre-disposing technical factors were identified. Finally, using NJR data, the effect of the introduction of cementless UKR on overall outcomes was examined. The number of cementless cases was small, and no significant effect on implant survival was demonstrated. However, patients undergoing cementless UKR demonstrated superior PROMs. These studies demonstrate that UKR has numerous advantages over TKR in terms of morbidity, mortality and PROMs. If surgeons perform high volumes of UKR (achievable by increasing their UKR usage), these advantages can be attained without the large difference in revision rates previously demonstrated. Cementless UKR is safe and provides superior fixation and outcomes in the hands of high-volume surgeons. Further work is needed to quantify the revision rate of cementless UKR, and to assess its results in the hands of less experienced surgeons.
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Ibeachu, Chukwuemeka. "Knee problems in young adults". Thesis, University of Central Lancashire, 2016. http://clok.uclan.ac.uk/16656/.
Testo completoAbstract (sommario):
Obesity and physical inactivity have been identified as risk factors for knee pain in elderly populations. There has been an increase in the prevalence of obesity and physical inactivity in younger adults. Therefore, it is important to investigate whether they are risk factors for knee disorders among young adults. This thesis explored the epidemiology of knee problems in young adults. A literature review, using systematic methods, identified 19 studies reporting on the incidence of and/or risk factors for knee disorders in young adults. Knee disorder incidence varied across studies (0.07% to 42.0%), because of the different knee conditions and study populations (military and sports) investigated. There was conflicting evidence on whether obesity and physical activity were risk factors for knee disorders; and physical inactivity had not been investigated. A longitudinal study was undertaken to estimate the incidence of knee problems in young adults and explore whether physical activity, physical inactivity and obesity were risk factors. It was designed as a feasibility study to inform a large-scale cohort study in the general population. Three hundred and fourteen staff and students of the University of Central Lancashire, Preston campus were recruited and followed up for 12 months. Data was collected through self-report questionnaire and where possible direct measurement of weight and height was taken. Logistic regression was used to investigate any plausible relationship between knee problems and body mass index (BMI), physical inactivity, and physical activity levels. The mean (SD) age was 22 (5.2) years. There were more men (n=176, 56.1%) than woman (n=138, 43.9%). At baseline, the mean (SD) score for the Hopkins Symptoms Checklist-10 (mental distress) was 1.5 (0.4); mean (SD) BMI was 24.3 (4.1) and mean (SD) total hours spent sitting per day was 5.6 hours (2.6). Over half of the participants (n=165, 52.9%) reported low physical activity with similar proportions reporting moderate (n= 75, 24.0%), and high (n= 72, 23.1%) physical activity levels. The prevalence of knee problems was high (31.8% [95% CI 26.9% to 37.2%]); knee pain was the most prevalent symptom. Multivariate logistic regression analysis on cross- sectional data showed that high physical activity levels (OR 2.6 [95% CI 1.4-4.9]) and mental distress (OR 2.3 [95% CI 1.2-4.6]) were independent risk factors. Only 126 (40.1%) participants responded to the follow up at 12 months: 76.9% still had knee problems and 11.5% had a new knee problem. Knee problems are common in young adults. The study provided an estimate of incidence to inform the design of a large-scale population based study but attention needs to be paid to ensure lower attrition. The study suggests that more attention may need to be paid towards prevention of knee problems and that further work on the economic burden of knee problems among young adults is warranted. This is particularly important as there is increasing emphasis in public health policy on promoting physical activity.
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Soni, Anushka. "Pain characterisation in knee osteoarthritis". Thesis, University of Oxford, 2015. https://ora.ox.ac.uk/objects/uuid:4026d694-8e7b-47f5-9f05-9f5a7b2165a0.
Testo completoAbstract (sommario):
Osteoarthritis (OA) is the most common form of arthritis in the world, and it has been estimated that about one tenth of the world's population, aged over 60, have symptoms that can be attributed to OA. Despite the size of the global impact of OA, there is a significant unmet need for effective treatments. Knee replacement surgery is commonly used in patients with moderate to severe knee OA, in order to reduce pain. However, 10-34% of patients report an unfavourable long-term outcome with persistent pain after surgery. The neural mechanisms for the generation of pain in knee OA are not fully understood. Previous work has shown that around 20% of patients have features of neuropathic pain, and that the underlying mechanism for this may be through central sensitisation. This mechanism-based understanding of pain is important in order to aid targeted intervention, and it may be that this patient group is more likely to have an adverse outcome following surgery. This thesis uses a combination of methods to investigate the neural mechanisms underlying pain experienced by patients with knee OA, across the full spectrum of disease severity. Quantitative sensory testing (QST) was initially used in a community-based cohort to show that pain sensitisation can be detected in early disease, and also contributes to the observed discordance between radiographic structural and symptomatic disease. The clinical relevance of neuropathic pain was then investigated in patients with knee OA, who were awaiting knee replacement surgery. Prior to surgery patients with neuropathic pain had increased sensitivity to experimental pain, as well as higher symptom severity and psychological distress. Functional magnetic resonance imaging (fMRI) was then used to confirm that these features were also associated with central sensitisation in the form of increased descending facilitation as well as reduced descending inhibition prior to surgery. The presence of neuropathic pain prior to surgery was associated with statistically and clinically significantly worse outcome following surgery, compared to those with purely nociceptive pain in the absence of any significant structural differences between the two groups. Taken together, this mechanism-based understanding of the pain provides an opportunity for targeted therapy prior to surgery, which may enhance outcome following surgery.
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Hamilton, Thomas. "Assessment of the arthritic knee". Thesis, University of Oxford, 2017. http://ora.ox.ac.uk/objects/uuid:6a36e359-defb-4ff3-a6b5-6f459c4c40f2.
Testo completoAbstract (sommario):
The aim of this thesis was to establish the long-term outcomes of the Oxford medial Unicompartmental Knee Arthroplasty (OUKA), define patient selection criteria and to develop and externally validate an evidence based method of patient selection for this procedure. In the hands of the developer surgeons, outcomes following medial OUKA were found to be good with an implant survival of 94% (95%CI 92 to 96) at ten-years and 91% (95%CI 83 to 98) at fifteen-years. Across the published literature, however, variation in outcomes was observed with a meta-analysis of published series of OUKA finding estimates of ten-year survival ranging from 57% to 100%, mean 88% (95%CI 85 to 90). It was identified that both increased surgical caseload (volume) and increased surgical usage (proportion of primary knee arthroplasty that are OUKA), a surrogate marker of indications, were associated with improved outcomes. Surgical usage, however, was more important, with good results following OUKA seen with high surgical usage, representing broad indications, independent of the surgical volume. This finding, coupled with differences in patient demographics and failure mechanisms between usage groups, highlighted that differences in indications for OUKA may explain the variability in outcomes observed. One reason surgeons may have a low usage is if they apply previously recommended patient factor contraindications based on age (<60 years), weight (&GE;82kg) and activity level (high activity). When disease factors are standardised, however, it was found that patients with these previously reported contraindications often actually did better than those without, and outcomes of knees implanted where all these factors were present were as good as where none were present. Therefore, the decision to proceed with OUKA should be based on the pathoanatomy of disease. Optimal candidates for OUKA should have full-thickness cartilage loss, with bone on bone arthritis, in the medial compartment, as knees with partial thickness cartilage loss were found to have worse functional outcomes and almost three-times the reoperation rate, predominantly for unexplained pain. Provided there was full-thickness preserved cartilage laterally and functionally normal ligaments, the presence of lateral osteophytes and the macroscopic status of the anterior cruciate ligament was not found to influence outcomes, nor did the presence of patellofemoral joint disease (with the exception of lateral facet disease with bone loss and grooving) or anterior knee pain. The pathoanatomy of disease can be identified radiologically, however, standing knee radiograph were found to perform poorly. To identify medial compartment full-thickness cartilage loss either a varus stress radiograph or fixed flexion radiograph, both at 20° flexion and aligned to the joint surface, were identified as the optimum views. To confirm preserved lateral compartment full-thickness cartilage a valgus stress radiograph at 20° flexion, aligned to the joint surface, was identified as the most appropriate technique. As stress radiographs are time and resource consuming, a novel stress device was developed in line with the IDEAL-D framework and validated against the gold standard of manual, clinician performed stress radiographs, as well as independently tested in clinical practice. Finally, to simplify patient selection, an atlas based Decision Aid, combined with a structured radiographic assessment, was developed and externally validated with an accuracy of over 90% at identifying suitability for OUKA. The routine use of this approach would be expected to standardise patient selection and ultimately translate into improved long-term outcomes.
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Tuncer, Mahmut. "Fixation of unicondylar knee prostheses". Thesis, Imperial College London, 2013. http://hdl.handle.net/10044/1/10967.
Testo completoAbstract (sommario):
There is increasing use of Unicondylar or Unicompartmental Knee Replacements (UKR), especially following publication of good survival data and a trend towards ‘minimally invasive surgery’. The UKR preserves one of the femoral condyles and its meniscus, plus both of the cruciate ligaments. Therefore, the knee functions more normally following UKR than after Total Knee Replacement (TKR). However, the odds for failure of the UKR are higher than the TKR, and a principal reason is loosening of the tibial and femoral components. There is a need for the development of more reliable UKR fixation designs. The overall aim of this research was to understand fixation of UKR and make recommendations for improvement to designers and surgeons. Since the Oxford mobile-bearing UKR is most widely used in the UK, it was used as the benchmark in this study. To assess initial fixation, in-vitro bone-constructs were prepared from ten cadavers implanted with the Oxford mobile-bearing UKR and tested for bone strain and bone-implant interface motion with the implants fixed using first cementless and then cemented methods. Cementless fixation produced higher proximal tibia strain and bone-implant displacement than cemented fixation. Peak bone strain increased with reduced bone density, such that the lowest density specimen fractured when implanted with the cementless UKR. To assess long-term fixation, an in-vivo prospective follow-up study of 11 Oxford UKR patients was developed and conducted for one-year, taking measurements of bone density using Dual X-Ray Absorptiometry (DXA) scanning. The average bone resorption under the tibial implant was found to be low; while it was higher under the femoral component and very high under the tibial intercondylar eminence. The fixation of the Oxford UKR implant was considered to be adequate at 1-year. Finite Element (FE) simulation techniques were reviewed and developed to simulate the UKR knee for investigation of bone strain, bone-implant interface micromotion and bone remodelling to assess initial and long-term fixation performance. Computer simulations of the tibiae and femora of 2 patients and 4 cadaveric specimens (obtained from the in-vivo and in-vitro studies) were developed and validated for bone strain, bone-implant interface micromotion and bone remodelling. Comparative multi-specimen computational studies were conducted to understand how particular design features affected fixation. Good fixation was indicated for cementless UKRs when implanted in dense bone, but bone strains were very high in low density tibia. Cementation of the implants spread the loads more evenly and reduced bone strains. The cementless tibial implant caused less bone resorption (compared to the cemented equivalent) but the difference in the femur was small. Bone resorption was highest at the anterior tibia and posterior to the femoral peg. Bone density was an important factor in the fixation performance of implant design features. Less bulky fixation features reduced bone resorption, provided that the underlying bone was sufficiently dense to maintain bone strains below the failure limit of bone. For patients with dense bone, fixation could be improved with shorter tibial keels and less stiff femoral implants. For patients with low density bone, fixation could be improved with cementation and bone resection that avoids creating stress-raisers.
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Roos, Harald. "Exercise, knee injury and osteoarthrosis". Lund : Dept. of Orthopedics, University Hospital, 1994. http://books.google.com/books?id=c25sAAAAMAAJ.
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