Total knee arthroplasty (TKA) is a common surgical procedure for the treatment of patients with pain and immobility as a result of osteoarthritis or rheumatoid arthritis. Pain-related interference, pain and nausea are recovery-limiting in these patients in the immediate postoperative period. Preoperative educational interventions that include pain communication and management information have been shown to decrease pain in joint replacement patients (McDonald & Molony, 2004). This randomized controlled trial compared usual preoperative education to an individually delivered preoperative education program. Participants (N=143) were randomized to intervention or usual care groups during routine preadmission testing. The usual care group received the usual preoperative teaching. The treatment group received the usual care teaching, a booklet containing content specific to symptom management after TKA, an individual teaching session during the preadmission testing visit and a telephone follow-up support call during the week before surgery. The primary outcome for this study was pain-related interference with activity and was measured using the Brief Pain Inventory Interference subscale (BPI-I) (Cleeland et al., 1994) on postoperative day three. Secondary outcomes were pain, nausea and expected postoperative activity and were measured on postoperative days one, two and three. There were no differences between groups in any of the outcomes for this study. BPI-I total scores were 24.4±14.4 in the intervention group and 22.4±15.1 in the usual care group (P=0.5) on the third postoperative day. Overall results demonstrated that although TKA patients had severe postoperative pain and severe nausea, they received inadequate doses of analgesia and anti-emetics. Available evidenced based protocols and practices in the health care environment were not followed Individualizing education content was not sufficient to produce a change in postoperative symptoms for these patients. Further research involving the modification of environmental and system factors affecting the provision of symptom management interventions is warranted.

Knee osteoarthritis is a debilitating disease causing pain and disability in adults. Biomechanical factors including obesity, abnormal magnitude and load distribution have been cited to play a role in its initiation and progression with its definite cause being multi-factorial. Total knee arthroplasty has become the treatment of choice for knee osteoarthritis and although the procedure is mostly successful, there are some patients who experience implant failures which necessitates revision surgery. Revision surgery is more complicated and thus there is the need to monitor patients who have undergone TKA so as ensure better outcomes and also address problems much earlier. Objective methods like Radiostereometric Analysis (RSA) has proven to be a good tool at diagnosing these implant failures. Inducible displacement with RSA has the potential to serve as a one-time measure to diagnose implant failures. Previous studies have applied loads to induce motion to the knee in various ways- squatting, exercising and weight-bearing on the affected limb. This was not standardized and caused wide variations in the data. This work looked at refining a device used to apply standardized loads to the knee resulting in a more portable and faster way of applying load to the joint. Gait analysis is used to assess implant function pre and post surgery. Some gait patterns have also been related to implant failure. Previous works have focussed primarily on associations between well-working implants (non-revised patients) and these gait patterns (adduction moments and flexion angles). This work focussed on any differences in the gait patterns between patients who did not undergo revision surgery and those that did. Although most parameter differences did not reach statistical differences, they point to important trends that may explain the causative factors (adduction moments) whiles others may point to the effects of disease progression (external rotation).

The history of total knee arthroplasty stretches back over 70 years. Many studies have shown that TKA is, in general, a successful operation for the relief of joint pain, with patient satisfaction rates of 90-95% and implant survival rates at 10-15 years of greater than 90%. However, a number of studies have also shown the potential for failures or complications arising post-implantation leading to revision surgery. This thesis presents finite element (FE) models of the distal femur following primary and revision total knee arthroplasty. Pre-arthroplasty models are also developed for comparison. Particular attention is given to how femoral component design and method of fixation impacts the mechanical environment of the distal femur and stability of the prosthesis. FE analyses with fully bonded interfaces indicate that femoral components are subject to areas of low stress (stress shielding) immediately under the anterior flange and chamfer regardless of internal implant features. However, internal implant features were found to play a role in the pattern and magnitude of stress concentrations. Both stresses and motions were observed to increase with increasing flexion angle, indicating the importance of testing at multiple angles. The initial models of the distal femur were extended to incorporate the effects of ageing and endosteal thinning of the femoral cortex, through novel application of pre-existing FE modelling techniques, specifically the ability to assign variable material properties corresponding to the nodal temperatures output from a heat transfer analysis. The findings from this study indicate that older patients with osteoporosis may be at increased risk of periprosthetic fracture compared to younger healthy patients. The use of a revision femoral component with a cemented stem as a means to mitigate this fracture risk was also investigated. FE analyses using frictional interfaces were employed to determine the influence of femoral component design on micromotion at the interface. These models showed that all primary implants were subject to similar magnitudes of relative motion at the interface, however, the distinct internal implant features led to very different regional variations. Furthermore, certain internal implant features (i.e. femoral box) were found to be highly sensitive to errors in surgical bone cuts. This aspect of the thesis also concluded that the addition of a stem served to significantly reduce motions at the interface in comparison to primary stemless implants. Long stemmed prostheses were found to result in the smallest levels of interface motion. This study also detailed the design and creation of an in vitro test setup for the purposes of determining the influence of stem length and fixation on the stability of revision prostheses. Experimental results using this test rig showed that a cemented short stem provides as much initial stability as the uncemented long stem, and is easier to fit surgically. Corresponding FE models incorporating a virtual representation of the test rig and in vitro loading conditions revealed that the relative motion at the multi-planar bone-prosthesis interface cannot be adequately described using a single reference point. However, in vitro setups may be used to predict a general measure of implant stability and to provide a source of calibration for FE. The distal femur models were further modified to investigate how the presence of condylar defects as classified by AORI defect classification system (Engh 2006) and weak osseous support due to osteoporosis may adversely affect the survival of the prosthesis. These investigations revealed that fixation of the femoral component, the presence of a large condylar defect and the level of osseous support all had an impact on stress in the implant, it is concluded that a non-modular approach should be adopted in older patient groups with severe osteoporosis to mitigate the risk of component junction failure and distal femoral fracture.

Increased workload on our healthcare system calls for more automation, this too in the pre-operative planning of total knee arthroplasty (TKA) surgery. This should keep in mind however that success in TKA is measured through having proper limb alignment. This thesis project implemented a virtual positioning assessment software that provides an initial position based on its bone and implant inputs with their specific landmarks. Positions can be furtherly adapted and evaluated based on flexion facets, obtaining decreased pre-operative workloads. The software was validated through an analysis comparison of the femur positioning of nine cases with the former used analysis tool of the university Hospital of Ghent. The newly implemented software was concluded to approximate the patients’ pre-operative alignment better for all translational and rotational parameters, except anteroposterior translation and internal/external rotation of the femur.

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Decreased gait symmetry has been correlated with an increased fall risk, abnormal joint loading and decreased functional outcomes. Therefore, symmetry is focused on in the rehabilitation of many patient populations. Currently, load based symmetry is collected using expensive and immobile devices that are not clinically accessible, but there is a clinical need for an objective measure of loading symmetry during daily tasks like walking. Therefore, the purpose of this dissertation was to 1) assess the validity and reliability of the loadsol® to capture ground reaction force data, 2) use the loadsol® to determine the differences in symmetry between adults with a TKA and their healthy peers and 3) explore the potential of a commercially available biofeedback system to acutely improve gait symmetry in adults. The results of this work indicate that the loadsol® is a valid and reliable method of collecting loading measures during walking in both young and older adults. TKA patients who are 12-24 months post-TKA have lower symmetry in the weight acceptance peak force, propulsive peak force and impulse when compared to their healthy peers. Finally, a case study with four asymmetric adults demonstrated that a 10-minute biofeedback intervention with the loadsol® resulted in an acute improvement in symmetry. Future work is needed to determine the potential of this intervention to improve symmetry in patient populations and to determine whether the acute response is retained following the completion of the intervention. / Doctor of Philosophy / Symmetry during walking is a valuable attribute as asymmetry has been correlated with an increased fall risk and decreased mobility. Currently, load based symmetry is collected using expensive and immobile devices that are not clinically accessible. As a result, there is a critical need for a system that can objectively measure load and loading symmetry during rehabilitation and everyday tasks in a variety of settings. A new device has been developed (loadsol®) that could potentially fill this need. Before it can be used to assess and treat patients, the loadsol® needed to be assessed for accuracy and reliability in both older and younger adults and at various speeds. Then we needed to determine if the loadsol® can be used to look at the levels of symmetry in patients who have had a knee replacement compared to their healthy peers. Finally, we tested a visual biofeedback intervention with the loadsol® to see if this intervention was able to improve symmetry. We found that the loadsol® is accurate and reliable. Patients with a knee replacement were less symmetric than their age matched peers. Finally, in a small study, the visual biofeedback intervention improved symmetry during walking in a group of people with less than 90% symmetry. Future work is needed to explore the potential of this biofeedback intervention to improve symmetry in various patient populations and to determine the extent to which patients are able to retain these improvements.

Résumé : Problématique: Près de 40% des 57 718 Canadiens ayant subi une arthroplastie du genou entre 2013 et 2014 étaient des travailleurs; la majorité étant âgée entre 55 à 64 ans. Des indices démographiques et législatifs laissent entrevoir que ce nombre continuera d’augmenter dans les prochaines années. Environ 15 à 30% de ces patients éprouvent des difficultés à reprendre ou à demeurer au travail six mois après la chirurgie. Malgré l’ampleur du phénomène, la perspective des travailleurs quant à ces difficultés demeure inconnue. Objectifs : Ce projet vise à mieux comprendre, selon la perspective du travailleur, les mécanismes sous-jacents à reprendre, ou non, une vie saine et active au travail à la suite d’une arthroplastie du genou. Plus précisément, il s’agit de décrire les représentations de l’incapacité au travail de ces travailleurs. Méthode : Ce projet qualitatif est basé sur une approche narrative avec comme cadre conceptuel le modèle d’autorégulation de Leventhal. Un échantillon de convenance de huit travailleurs ayant eu une arthroplastie du genou et éprouvant des difficultés à reprendre ou à demeurer au travail a été recruté. Des entrevues individuelles semi-dirigées ont été conduites. La méthode de Landry a été suivie pour le codage. D’abord, le cadre conceptuel a permis l’élaboration du cahier de codification tout en laissant la place à des codes émergents. Une analyse thématique des verbatim a ensuite été réalisée à l’aide du logiciel AtlasTi par deux codeurs indépendants (PM et MFC) qui ont discuté des codes divergents. Une fois toutes les entrevues codées, des réunions en équipe multidisciplinaire (kinésiologue, psychologue et physiothérapeute) ont eu lieu pour discuter de chaque cas et profiter de l’expertise de chacun des membres de l’équipe pour une analyse en profondeur. Résultats : La moitié des travailleurs rencontrée était absente du travail au moment de l’entrevue. L’émergence de cinq thèmes principaux a permis d’identifier deux cas types, soient retournés au travail avec difficultés, mais présence de soutien, et non retournés. Les travailleurs de la première trajectoire rapportent une implication de l’entreprise dans les démarches de retour au travail et ont les conditions nécessaires pour prendre des moyens actifs afin d’améliorer leur condition. Pour les travailleurs de la deuxième trajectoire, différents obstacles nuisent à la reprise des activités dont des complications postopératoires, une perception d’exigences de travail élevées, un faible soutien de l’environnement de travail et peu de ressources pour les aider. Conclusion : L’identification d’une trajectoire qui est moins favorable au retour au travail permet d’identifier les travailleurs à risque d’être en situation d’incapacité au travail. Ces travailleurs pourraient bénéficier de services en réadaptation au travail pour favoriser la reprise d’une vie saine et active après l’arthroplastie du genou. / Abstract : Purpose: Nearly 40% of the 57,718 Canadians who underwent total knee arthroplasty (TKA) between 2013 and 2014 were workers; the majority of them were aged from 55 to 64 years. Demographic and legislative indications suggest that this number will increase in the coming years. Actually, 15 to 30% of these patients report limitations at work or are not able to return to work six months after the surgery. Despite this growing phenomenon, workers’ insight on what influence work disability remains unknown. Objectives: The purpose of this study is to understand the worker’s perspective on what contributes or impedes the return to an active working life after TKA. Specifically, we aimed to document workers’ representations of their disability following TKA. Method: This qualitative study was conducted based on a narrative approach using Leventhal’s Common Sense Model (CSM) as the conceptual framework. A convenience sample of eight workers experiencing limitations while at work or being fully disabled (on sick leave) after TKA was interviewed. We conducted semistructured interviews, and then we followed Landry’s method for coding. First, we used a mixed coding method whereby codes were established a priori using the CSM with the possibility for emergent codes. Second, two researchers (PM and MFC) independently coded all interviews, compared the codes, and discussed diverging results. Third, after coding all interviews and based on the coding, content analysis was performed in multidisciplinary team (psychologist, physiotherapist, kinesiologist). Each interview was discussed by the team to compare the analysis and to obtain consensus as we believe our disciplinary backgrounds might impact interpretation of the data by bringing new information to the case. Content analysis was performed with Atlas-Ti software. Results: Half of the workers were fully disabled because of TKA. We identified two typical cases: workers who returned to work with difficulties but perceived support from their environment and workers who did not returned to work. The workers that returned to work reported involvement of their work environment in the return-to-work process. They felt they had greater improvement after TKA, and this enables them to further improve their condition. Workers who did not return to work encountered various obstacles such as ostoperative complications, a more physically-demanding job, negligible support from their work environment, and few resources to help them. Conclusion: The identification of a case that is less favorable to return to work allowed us to identify workers at risk of work disability. These workers could benefit from work rehabilitation services in order to promote a better active working life after TKA.

Aseptic loosening of the tibial component is an important cause of failure after total knee arthroplasty. Bone destruction often claimed to be caused by the cement makes the revision difficult. In order to treat younger patients, uncemented fixation has been introduced, but the etiology to loosening is multifactorial and only partly known. Early detection of implant migration facilitates research in this field but is difficult using conventional techniques. In this study modified versions of roentgen stereophotogrammetric analysis (RSA) were developed to obtain accurate and standardized evaluations facilitating comparison between prosthetic designs. The method was used to record the efficacy of cemented and uncemented fixation of different designs of the tibial component, to determine the accuracy of scintimetry in the detection of early aseptic loosening, and to analyse the in vivo kinematics of knee arthroplasties with different design and stability between the joint surfaces. Forty-three arthroplasties with comparatively high inherent stability of the joint surfaces were randomized to cemented or uncemented fixation of the tibial component. In all groups micromovements were rather large, but with no differences between the cemented and uncemented components. The preoperative diagnosis (arthrosis OA, n=25; rheumatoid arthritis RA, n=18) did not influence the magnitude of micromotion. 20 arthroplasties with the same design as above but equipped with an intramedullary stem, were randomized to cemented or uncemented fixation in patients with RA. Cement improved the fixation. Uncemented stemmed components displayed micromovements seemingly larger than unstemmed ones. 34 arthroplasties with an unconstrained design of the joint area and fixed to the tibia with four pegs were randomized to cemented or uncemented fixation in patients with OA. When used uncemented 4 screws were added. Compared with previously investigated designs small micromotions were recorded, and especially in the cemented cases. Uncemented components with thin polyethylene inserts displayed larger initial micromotions. The preoperative deformity influenced the direction of the micromotion. 33 knees were followed prospectively with RSA and scintimetry to evaluate any correlation between these methods. Low activity under the tibial component at 2 years implied prosthetic stability, whereas high activity indicated instability or high bone remodelling caused by the preoperative malalignment. The in vivo kinematics in three different designs of knee arthroplasties were analyzed during active flexion and extension without weight-bearing. Each type of prosthesis displayed design-specific abnormalities when compared with a normal material. Pronounced posterior tibial translations were recorded during flexion regardless whether the posterior cruciate ligament had been sacrificed or not. Data from the kinematic and the fixation studies suggest that movements restricted by the design of the joint area are transmitted to the bony interface with design-specific micromotions as the result. Analysis of knee joint kinematics during extension and weight-bearing revealed small alterations compared with non-weight-bearing. Evaluation of the three-dimensional movements in terms of helical axis rotations and translations confirmed the constrained or unconstrained in vivo behaviour of the designs under study. This analysis also facilitated the interpretation of the kinematic behaviour of the prosthetic knees and may be of value in the evaluation of new designs. / <p>Diss. (sammanfattning) Umeå : Umeå universitet, 1992, härtill 7 uppsatser.</p> / digitalisering@umu