The purpose of this integrated review of the literature was to explore the postsurgical infection complications commonly occurring in individuals undergoing total knee replacement surgery, and the relationship of co-morbidities, lifestyle choices, and genetics on the risk for complication. A comprehensive search of the literature focusing on the patient surgical site infection and total knee replacement surgery using the Cumulative Index to Nursing and Allied Health Literature (CINAHL) and Medical Literature On-line (MEDLINE). Initial searches revealed 80 results. Upon closer scrutiny, duplicates were removed, as well as those not relevant to infection in total knee arthroplasty. This resulted in a review of 6 articles that fit the inclusion criteria. Inclusion criteria were articles written in the English language and published in scholarly, peer-reviewed, journals from 2009 to present. In addition to published articles, pertinent material from current nursing textbooks was evaluated and chosen to further substantiate the literature results. In cases of knee arthroplasty, diagnoses of obesity and diabetes were discovered to be risk factors for postsurgical infection. The findings of this thesis offer interpretation for nursing practice, research, education, and policy. Implications for nursing research, policy, education and practice are highlighted along with limitations of this integrative review.

Knee osteoarthritis (OA) is a progressive disease that ultimately requires patients to receive a total knee arthroplasty (TKA) to replace the damaged structures within the knee with an artificial joint. Surgeons have many options when selecting an appropriate implant. Patients want a TKA that feels 'normal' and allows them to perform most activities without pain, stiffness, and other residual symptoms. However, 20% of patients remain unsatisfied with their surgery, regardless. This thesis aimed to examine the effect of implant selection during TKA on knee biomechanical function during various ADLs. Several gaps were identified within the review of literature: 1) patient-reported outcome measures cannot differentiate between medial ball and socket (MBS) and posterior stabilized (PS) implants, 2) most biomechanical studies were performed only in postoperative patients, and 3) studies that compared MBS and PS implants were primarily focused on level walking conditions, and overlooked tasks that placed more demand on the knee joint. Twenty-eight individuals with severe knee OA were randomized to receive either an MBS (n=14) or PS implant. They completed a biomechanical assessment within one month and one year after TKA and were compared to 14 controls of similar age, sex, and body mass index. They performed a variety of tasks which explored three main areas: 1) examine the alterations in gait variability among individuals with OA following a TKA procedure using either a PS or MBS implant; 2) enhance the understanding of the post-operative effects of TKA with either MBS and PS implants on knee biomechanics and muscle activities during level walking, as well as more demanding tasks such as descending a ramp or staircase; 3) simulate the dynamic knee joint loads in post-operative TKA patients with either PS or MBS implants during closed-chain, bilateral tasks such as sit-to-stand. Initially, a series of studies were performed to develop a new test called waveform-level variance inequality test (eqvartest), which had not been previously utilized in the literature. This test was used to identify discrepancies in gait variability pre and post-TKA in the gait cycle. Following TKA, patients showed decreased variability in knee moment and power at single-limb support. Neither the MBS nor PS implant provided the same level of variability as the control group, demonstrating reduced knee joint stability. The MBS group had a gait pattern closer to the control group during level walking, whereas the PS group walked with a stiffer knee. However, during more demanding ADLs, the differences were less apparent. During ramp descent, knee joint stability issues became prominent as MBS and PS groups adopted a 'cautious gait pattern,' widening their base of support and stiffening their knee to reduce loading. During stair descent, the MBS implant provided increased stability as it required less muscle activity than the PS, requiring greater hamstring muscle activation. During sit-to-stand, MBS and PS groups favoured their non-operated knee as they had reduced total vertical, medial, and lateral KCF on their operated knee compared to their non-operated side. This may be due to compensatory strategies developed through the progression of knee OA and may increase the risk of developing knee OA on the non-operated limb. The outcomes of this thesis can assist clinicians in selecting the most appropriate implant for their patients and guide them in designing rehabilitation programs that can enhance patient function following TKA.

Medial Oxford unicompartmental knee replacement (UKR) is an established and successful treatment for patients with antero-medial knee osteoarthritis. However, following the operation some patients have pain which compromises their functional outcome. The aims of this thesis were to determine the incidence of pain, to identify the patient, disease and surgical risk factors associated with this pain and to try and understand why it occurs. The clinical studies were performed using patients operated on by experienced surgeons. The incidence of post-operative severe pain was 3% at six weeks and 2% at one year and the incidence remained unchanged at subsequent follow ups. The overall incidence of pain has reduced over the years. In patients who had UKR between 1998 and 2001, the incidence of severe pain was 5%; this reduced to 2.3% for the period between 2008 and 2011. As the indications have not changed, the improvement is probably due to modifications in the surgical technique and due to improvements in instrumentation. Patients with severe pain at the final follow up had a worse neuropathic pain score, and the patients with possible pre-operative neuropathic pain achieved significantly worse outcome. To explore the effect of disease severity on outcome, matched cohorts of patients with partial thickness cartilage loss (PTCL), bone-on-bone and bone loss were compared. All those with bone-on-bone and bone loss did well, whereas 20% of those with PTCL did not benefit from the surgery; 7% had severe pain and 17% had pain related complications. Although component and leg alignment, and component overhang have a profound effect on the outcome of total knee replacement (TKR), their effect on the outcome of the Oxford UKR are not known. It was found that malalignment in the coronal or sagittal planes of the femoral component within ±10° and of the tibial component within ±5° did not compromise the outcome. Leg alignment was not related to outcome even though 18% were in 5° varus and 8% were in 10° varus. In contrast, tibial component overhang ≥3 mm compromised the outcome and 21% of these patients continue to suffer from pain. The presence of radiolucent lines (RLL) following a joint replacement is usually deemed to be indicative, or predictive, of loosening. 63% of Oxford UKRs were found to have RLL under the tibial component. No correlation was found between RLL and outcome, particularly pain. It has been suggested that post-operative pain, which is commonly antero-medial over the proximal tibia, may be related to bone overload. This was explored using the finite element (FE) analysis. Following implantation of the Oxford UKR, the strains in the antero-medial region doubled. Various implantation, loading and alignment variables were studied and the findings correlated with the clinical studies, suggesting that high strain is an important cause of pain. With time, the bone will remodel, so the strains will decrease but individual differences in the remodeling threshold may explain resolution of symptoms in some, but not in all, patients. In conclusion, this work has shown that following the Oxford UKR, pain is a rare but important complication. The chance of pain can be decreased by operating only on patients with bone-on-bone arthritis and taking care with the surgical technique. Bone overload is likely to be an important cause of pain, and further modification to the implant or technique, such as achieving fixation of the tibial component vertical wall to bone, may further decrease the incidence of pain.

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.

published_or_final_version / Medical Sciences / Master / Master of Medical Sciences

Conventional anterior cruciate ligament (ACL) reconstruction grafts have not been able to replicate the mechanical behaviour of the native ACL, reproduce normal knee mechanics and kinematics, or prevent degenerative disease progression of the knee. The aim of this thesis was to investigate a novel ACL design to more closely mimic the normal mechanical behaviour of the ACL, reconstruct the isometric ACL fibre and potentially reproduce the normal kinematics and mechanics of the knee. The designed artificial ACL reconstruction (ACLR) system could be used as a stand-alone device or in conjunction with a total knee replacement (TKR). The nominated design option for the ACLR system consisted of a connecting cord made of ultra-high molecular weight polyethylene (UHMWPE) fibres and an elastic system made of cobalt-chrome-molybdenum (CoCrMo) alloy with similar load-elongation characteristics to the native ACL. The design requirements were defined based on the mechanical properties of the native ACL, size constraints from the bony geometry and TKR components, and the location of the isometric fibres of the native ACL. The in vitro mechanical tests performed in this project on the designed cord showed a 2-3 times greater ultimate tensile load compared to the ACL in young human cadavers. The decreasing creep modulus of the UHMWPE cord under fatigue loading in simulated body conditions (3118 MPa at 6.5×10⁶ cycle) indicated nominal creep and stabilised mechanical properties by the 3000^th loading cycle. To replicate the non-linear stiffness of the ACL with ~38 N mm^-1 toe and ~100 N mm^-1 linear regions, the artificial ACLR device consisted of a femoral spring (~60 N mm^-1) in series with a tibial spring (~100 N mm^-1) and a connecting cord (~2000 N mm^-1). Two helical springs in series were used for the stand-alone ACLR, whereas a helical spring in series with a spiral spring was designed for the ACLR-TKR. As both the helical and spiral springs had a constant stiffness, stop mechanisms were added to the springs to create a non-linear stiffness and control the maximum safe deformation limit of each spring. To understand the mechanical behaviour of the reconstructed isometric fibre of the ACL, passive and loaded motions were simulated in 18 sets of segmented MRI models of healthy human knees. Constant load and elongation was observed throughout flexion during the passive movements, whereas maximal load and elongation in the reconstructed ACL was identified at 50 º of flexion during loaded motion. An ACL attachment placement sensitivity study, conducted in this project to assess the effect of surgical implantation error on the behaviour of the reconstructed ACL, revealed that misplacement of the femoral attachment would significantly influence the load-elongation of the reconstructed ACL. Finite element (FE) models of the designed ACLR devices enabled their behaviour under simulated axial loading, squatting and the Lachman test to be assessed. Both ACLR devices successfully reproduced stiffness of the native ACL with a multi-linear stiffness curve, however, elongation greater than 3.1 mm could not be achieved. It can be concluded that the designed artificial ACLR devices were able to mimic the mechanical behaviour of the ACL provided it was positioned at the isometric attachment points; potentially enabling achievement of more natural kinematics and mechanics of the reconstructed knee. However, ACL placement was shown to have a significant impact on the behaviour of the reconstructed ACL, therefore, placement error may over-constrain the joint. For this reason, a more forgiving design with a lower stiffness and a larger deformation limit would be advised.

The Oxford Knee Score (OKS) is a popular single summary questionnaire developed to measure the effect of knee replacement surgery from the patients' perspective. There has been a recent interest in the use of the OKS in populations of patients and in roles it has not been originally developed for. To date, no evidence has been provided about the measurement properties of the OKS when it is used outside the context or purpose for which it was originally designed. The general aim of this thesis is to investigate the measurement properties of the OKS when used in extended roles: a) within the population for which the OKS was originally intended and developed for (knee replacement) and, b) when applied on a different population, viz. patients undergoing non-operative treatment for knee osteoarthritis (OA). Four existing large-scale databases of patients undergoing knee replacement surgery and a database obtained from a prospective study on patients undergoing non-surgical management for knee OA were analyzed. The results demonstrate that: 1) it is possible to extract separate information on pain and functional disability from the OKS in a meaningful way (in the form of subscales). 2) For the first time, anchor-based Minimal Important Change (MIC) of 9 points and Minimal Important Difference (MID) of 5 points were established for joint replacement surgery. 3) The OKS demonstrated satisfactory evidence reliability, validity, responsiveness, and interpretability, when used in patients who are undergoing non-operative management for their knee OA. 4) Further evidence of validity was demonstrated by fitting the OKS to the Rasch model. 5) Lastly, it was demonstrated that thresholds can be applied on the OKS to distinguish between patients who consider their knee problem to be severe enough to warrant joint replacement surgery versus patients who do not. This supports the potential use of the OKS in decision making aids for secondary care referral. Overall the thesis provides critical evidence, not previously existing, to support the continued use, and extended use, of the OKS in orthopaedic medicine.

Submitted by Ana Lúcia Torres (bfmhuap@gmail.com) on 2017-10-04T13:09:23Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Tese Ricardo Bastos.pdf: 1699294 bytes, checksum: 9f66927af352d688894773afaee06cdd (MD5) / Approved for entry into archive by Ana Lúcia Torres (bfmhuap@gmail.com) on 2017-10-04T13:09:37Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Tese Ricardo Bastos.pdf: 1699294 bytes, checksum: 9f66927af352d688894773afaee06cdd (MD5) / Made available in DSpace on 2017-10-04T13:09:37Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Tese Ricardo Bastos.pdf: 1699294 bytes, checksum: 9f66927af352d688894773afaee06cdd (MD5) Previous issue date: 2013 / Universidade Federal Fluminense / Osteotomia tibial alta (OTA) é um recurso frequentemente utilizado para o tratamento da artrose de joelho em pacientes jovens com o objetivo de retardar a necessidade de uma artroplastia total de joelho (ATJ). O objetivo do estudo foi de avaliar a influência da técnica de OTA (adição ou subtração) no resultado final da ATJ e comparar a sobrevida das cirurgias de osteotomias com a idade dos pacientes no momento do procedimento Nossa hipótese é que o alinhamento do membro, seguimento clínico dos pacientes e taxa de complicações sejam iguais em pacientes submetidos a ATJ após OTA de adição e subtração além de que as osteotomias de subtração apresentem uma maior duração até a ne-cessidade de realização da ATJ. Supomos também que a idade dos pacientes na época das osteotomias tenha uma relação linear positiva com a sobrevida desta cirurgia. Cento e quarenta e uma ATJs com antecedente de cirurgia de OTA (24 osteotomias de adição e 117 de subtração) foram selecionadas. Fatores intra-operatórios, resultados clínicos e alinhamento do membro foram analisados. A duração (sobrevida) das 2 diferentes técnicas de osteotomia até a realização da ATJ, assim como o impacto da idade dos pacientes na duração das duas técnicas desta cirurgia, também foram observados. Não foram observadas diferenças significativas nos escores IKS quando comparadas as duas técnicas cirúrgicas. Foi observada uma tendência a maior necessidade de uma osteo-tomia da tuberosidade anterior da tíbia (TAT) no grupo das osteotomias de subtração. Foi encontrada uma maior necessidade de liberação de partes moles (release) medial mais extensa no grupo das osteotomias de adição e uma liberação de partes moles lateral mais importante no grupo das osteotomias de subtração. Não foram encontradas diferenças no tempo de is-quemia, taxas de complicação ou no eixo mecânico final do membro inferior entre os dois grupos. O alinhamento radiográfico, resultados funcionais, objetivos e taxas de complicações são iguais em pacientes que se submetem a uma ATJ após a realização de uma OTA de adição e de subtração. A cirurgia de osteotomia tibial alta de subtração parece apresentar uma longe-vidade (sobrevida) maior até a necessidade da realização de uma artroplastia total de joelho quando comparada a uma osteotomia tibial de adição. Existe uma relação positiva e significa-tiva entre a idade do paciente na época da realização da osteotomia e a duração dessa cirurgia até a necessidade de uma artroplastia / High tibial osteotomy (HTO) is frequently used to treat varus osteoarthritis in younger patients with the goal of delaying the need for total knee arthroplasty (TKA). While it has been reported that the results of TKA following HTO are worse than those in patients without prior knee surgery, the influence of osteotomy technique (medial opening-wedge versus lat-eral closing-wedge) has not been explored. The purpose of this study was to evaluate the in-fluence of HTO technique on the performance and results of TKA. Our hypothesis is that the limb alignment, clinical follow-up and rate of complications are equal in patients undergoing TKA after closing-wedge and opening-wedge osteotomies and that the closing-wedge osteotomies have a higher survival rate when compared to open-ing- wedge osteotomies. We also suppose that younger patients at the time of the osteotomies have a longer delay until the need of performing a TKA. A hundred and one TKA’s performed in 118 patients with prior HTO (24 opening wedge and 117 closing wedge) were reviewed at a mean follow-up of 2 years. Reviewed data included intra-operative factors (tourniquet time, the need for additional exposure, and intra-operative complications), clinical results (International Knee Score (IKS)), and radiographic assessment of limb alignment. There was no significant difference in IKS scores based on osteotomy technique. There was a trend toward an increased need for tibial tubercle osteotomy in the closing-wedge group. There was an increased need for extensive medial release in the opening-wedge group and extensive lateral release in the closing-wedge group. No differences in tourniquet time, complication rates, or hip-knee-ankle angle were noted between the two groups. Radiographic limb alignment, patient-reported outcomes, and complication rates are equal in patients undergoing TKA after opening and closing wedge HTO. Closing-wedge high tibial osteotomy has a longer survival until the necessity of a total knee arthroplasty when compared to an opening-wedge high tibial osteotomy. There is a posi-tive and significant relationship between the patient's age at the time of the osteotomy and the survival of this surgery

The results of total knee arthroplasty are inferior in younger patients. The challenge today is therefore to develop designs and concepts that will last at least 25 years. This thesis has evaluated the fixation to bone of modern designs of knee prostheses uring RSA analysis. Coating implant surfaces with hydroxy-apatite have proven to enhance fixation to bone. Addition of screws for fixation of the tibial component enhances the fixation, but has negative side effects such as osteolysis around the screws, in turn leading to a higher risk of component loosening. The magnitude and pattern of migration was studied in a randomized study of uncemented tibial implants coated with hydroxy-apatite with and without additional screw fixation in patients younger than 65 years. The uncemented implants migrated initially more than the cemented implants that constituted the control group. Both uncemented groups stabilized at 3 monthes with no further migration, while the cemented implants showed a continuous migration up to the 2 year follow-up, indicating continuous bone resorption at the implant-bone interface, a fact that might lead to an increased risk of late implant loosening. This may not be a problem in older patients, but may have consequences for long-term fixation in younger patients. There was no difference between the two uncemented groups indicating that screws do not improve fixation. Hydroxy-apatite coated knee implants might be well suited for younger patients. Mobile bearing total knee arthroplasty theoretically uncouples the forces at the implant-bone interface, thus improving fixation of the implant to bone. The magnitude and pattern of migration of a cemented mobile bearing knee arthroplasty and a fixed bearing total knee arthroplasty was compared in a randomized study. The results showed that mobile bearings did not improve fixation. Trabecular metal, a new material recently introduced for total knee arthroplasty, has several theoretical advantages. Trabecular metal tibial implants were evaluated in a randomized study in patients younger than 60 years. The implants displayed the typical migration pattern for uncemented implants with greater migration initially followed by early stabilization. The majority of the trabecular metal implants subsided into the bone with no lift-off. Lift-off has the potential of exposing the interface to joint fluid with the potential risk of bone resorption and late loosening, and is commonly seen in metal-backed implants. The finding of absence of lift-off is regarded beneficial for uncemented fixation. Trabecular metal tibial implants might be suited for younger patients. The optimal mode of fixation of the femoral component is yet to be established. Comparing cemented femoral components with uncemented femoral components in a randomized study in patients younger than 60 years revealed no differences of the magnitude or the pattern of migration. Uncemented femoral component seems equally as good as cemented components in younger patients.

Traditionally, orthopaedic surgical training has primarily taken place in the operating room. Given the growing trend of decreasing resident work hours in North America and globally due to political mandate, training time in the operating room has generally been decreased. This has led to less operative exposure, teaching, and feedback for orthopaedic surgery residents. To solve this problem, a 3D serious game that was designed for the purpose of training orthopaedic surgery residents the steps comprising the total knee replacement procedure. Real-time, 3D graphical and sound rendering technologies are employed to provide sensory realism ensuring that the knowledge gained within the serious game can be more easily recalled and applied a real world scenario. A usability study to address user perceptions of the game’s ease of use, and the potential for learning and engagement was conducted. Results indicate that the serious game is easy to use, intuitive, and stimulating. / UOIT