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No description available.

No description available.

Over the past 50 years, the demographics of medical school graduates in the United States has changed dramatically with the number of women (47%) almost equaling the number of men in 2014 (AAMC, 2014). However, the Association of American Medical Colleges (2014) reports that orthopaedic surgery has the lowest proportion of female residents, instructors, assistants, associate, and full professors of all the sub-specialties and little has changed in the past several decades. Due to the healthcare reform and the changing needs of our society, it is importance to recruit, retain, and promote women into leadership positions. The purpose of this study is to ensure the success of women in orthopaedic surgery. A self-report survey was sent to all known women in orthopaedic surgery. The survey assessed perspectives of women in orthopaedic surgery in regards to organizational culture, leadership development, challenges, diversity, gender bias, recruitment, and retainment. An examination of the data provides insights into areas of improvement and implications for institutional practice. The results indicated that although institutions are making progress, more advocacy for gender equality, pro-family policies, and employee retention is needed.

Tendon, ligament, and joint capsular injuries represent 45% of the 32 million musculoskeletal injuries each year in the United States. Tendon injuries are especially common, requiring surgical repair for the shoulder’s rotator cuff tendons (51,000 per year), the Achilles tendon (44,000 per year), and the patellar tendon (42,000 per year). Tissue engineering provides an alternative in the treatment of tendon lesions through replacement of an injured tendon segment. The purpose of this study was to develop a tendon construct in vitro for clinical reconstructive surgery. Human tenocytes were isolated from hamstring tendons of patients who had undergone anterior cruciate ligament (ACL) surgeries. These tenocytes were cultured with culture media (α-MEM) supplemented with various concentrations of foetal bovine serum (FBS) (0%, 1%, 5% and 10%) and in the presence of different growth factors such as PDGFBB (0, 5, 10 and 50ng/ml), basic FGF (0, 5, 10 and 50ng/ml), IGF-1 (0, 10 and 50ng/ml) and TGFβ-3 (0, 1 and 10ng/ml). Fractional factorial design was utilized to select the combinations of growth factors that supported the following criteria: (1) the maximal cell proliferation with a minimum differentiation of the tenocytes in the presence of the least concentration of FBS possible and (2) maintaining cell survival and promoting tenocyte differentiation in FBS free culture media. The results have shown that: (i) The tenocyte cell number when cultured for 14 days in media supplemented with 1% FBS, 50ng/ml PDGFBB and 50ng/ml bFGF matched that of the positive control (10% FBS-treated cells). Not only was the collagen synthesis significantly reduced in these growth factor-treated cultures compared to positive control tenocytes, but also a significant inhibition of the mRNA expression of various tenocyte differentiation markers (Scleraxis, Tenomodulin, Collagen type I and Decorin) was evident. IGF-1 did not promote significant cell proliferation under low serum conditions but did induce tenocyte differentiation in vitro. Examination of the cell morphology confirmed that tenocytes were capable of less differentiation when cultured with 1% FBS, 50ng/ml PDGFBB and 50ng/ml bFGF, this culture condition was termed “the expansion phase”; (ii) The cell survival was maintained for up to 14 days in serum free culture media supplemented with 50ng/ml IGF-1 and 10ng/ml TGFβ-3 whilst cell differentiation was enhanced and evident by the increase in collagen synthesis and cell morphology. Furthermore, mRNA expression of the aforementioned cell differentiation markers were also significantly increased, this culture condition was termed “the differentiation phase”; (iii) By combining the culture condition optimized for the expansion and differentiation phase sequentially, it was possible to maintain a long term 2-D tenocyte culture in vitro for up to 28 days. In these cultures, the presence of dense collagen formation was clearly evident whereas in positive control group (10% FBS group) such observation was not noted even after prolonged culturing period of up to 45 days. These results suggested that the sequential treatment of tenocytes with growth factors identified for the expansion and differentiation phases was significantly more superior than the standard 10% FBS treatment; (iv) By combining the expansion and differentiation phases optimized for the 2-D cultures, it was possible to maintain human tenocytes in a 3-D scaffold (Bombix silk) for up to 28 days. The tendon like constructs that were formed, macroscopically and microscopically resembled the human hamstring tendon. This observation was confirmed by using H&E staining, scanning electron microscopy and by detecting collagen type I immunohistochemically; (v) It was possible to further validate these findings using in vivo animal models. This was undertaken by implanting the tenocytes cultured sequentially in the defined culture media described above, into the quadriceps of Balb/c nude male mice for up to 30 days. The nature and specificity of the tendon like structure that was formed after this implantation was investigated by H&E staining and immunohistochemistry. It was revealed that the culture conditions that were optimized during the expansion and differentiation phases were suitable for generating a human tendon reconstruct; a finding which is of significance due to its potential for tendon reconstructive surgery.

Anteromedial Gonarthrosis (AMG) is a distinct phenotype of knee osteoarthritis (OA), with a specific pattern of disease on the tibia. There is full thickness cartilage loss anteromedially, progressing to an area of damaged cartilage, and then to an area of macroscopically and histologically normal cartilage posteriorly. This reproducible pattern of disease can be considered to be a spatial model of OA progression and provides an alternative and less biologically varied set of specimens than the commonly used multiple joint compartments in which to quantify disease-related changes. The aim of this thesis was to explore in detail spatial and quantitative differences in cell, matrix and molecular features between areas of cartilage in AMG. A real time PCR study was undertaken comparing damaged and undamaged cartilage in AMG. Previous work from our research group had shown increased type I collagen content of undamaged cartilage in AMG. This gene expression study corroborated this finding by demonstrating increased COL1A1 expression in undamaged cartilage, compared to damaged cartilage. MMP1, MMP3, MMP13 and ADAMTS4 were also shown to have increased expression in undamaged cartilage. Since these changes arise in tissue before any macroscopic damage is apparent, these may indicate early changes of the cartilage matrix in AMG. In order to confirm that these changes are directly related to the damage process and not only to normal regional variations, Above Knee Amputations were collected from patients with peripheral vascular disease but no overt OA and a template of the AMG joint surface created to allow for matched regional sampling. Studies into their histology, immunoassays and qPCR were performed in order to compare results with those from AMG specimens. Histology demonstrated low scores throughout but allowed for a division into lower (macroscopically and histologically normal) and higher grade (surface wear/possible early signs of OA) groups. Immunoassays showed elevated type I collagen in high grade but not low grade groups in the posterior cartilage. No differences in mRNA expression were detected using qPCR suggesting that changes seen in AMG specimens were specific to the OA disease process. Because the causes of cell death in OA are not fully understood an immunohistochemical study into apoptosis was performed. TUNEL staining demonstrated higher levels of apoptosis, the more damaged the cartilage. The presence of Active Caspase 3, Cytochrome C, Active Bax and Bim with the same distributions demonstrated apoptosis occurring via the intrinsic or mitochondrial pathway. The high levels of 3-Nitrotyosine in more damaged cartilage implicated reactive oxygen species in apoptotic mechanisms. A microarray study was conducted comparing regions of damaged and undamaged cartilage in AMG. 389 genes were found to be significantly differentially expressed between regions. Several pathways rich in gene expression changes were highlighted including cellular development, inflammatory response and skeletal disorders. Results suggest complex changes in the signaling microenvironment of AMG and identify areas for future study. In summary, this thesis has highlighted several quantitative molecular and cellular differences between regions of cartilage in AMG, demonstrating its usefulness as a tight disease model. Gene expression differences corroborate changes previously seen by immunohistochemistry; microarray has shown the wider picture of gene expression changes. Apoptosis has been shown to occur via the intrinsic pathway and involve reactive oxygen species, highlighting this damage pathway as an important driver of cell loss. Most importantly this thesis has identified the apparently normal region in AMG specimens as a region undergoing considerable molecular changes and as a potential early disease model. The dysregulation of collagen I distribution seen in AMG and slightly worn AKA specimens is very interesting and suggests a possible early response to loading alterations caused by joint wear and opening the way for future experiments. The identification of wear patterns in AKA specimens specifically mapping to the zone of maximal damage in AMG confirms the site of initial injury and progression over time proposed in this model. These AKA specimens with no overt OA should therefore be used in future studies to assess emerging biomarkers of disease progression.

Bisphosphonates (BPs) are stable analogues of pyrophosphate widely used for the treatment of bone diseases characterised by increased bone resorption. Studies over the years have shown that the pharmacological potencies of BPs are dependent both on their binding affinities for bone mineral and on their inhibitory actions on osteoclasts. In addition, potential effects on other cell types present locally in the environment of skeletal tissues have been reported. The present study systematically evaluated the relative mineral-binding affinities of individual BPs of clinically relevance in mixtures of these compounds and the changes with elution pH by using column chromatography with ceramic hydroxyapatite and fluoroapatite combined with mass spectrometric identification and quantitation of the individual BPs. The results indicate that pH has a profound effect on the ionisation of the phosphonate and R2 functional groups, with BPs having greater affinities at lower pH as shown by increased retention times. Moreover, two other approaches, namely using Langmuir adsorption isotherms and competition assays based on fluorescent BP, have been developed to assess the mineral-binding capacities and dissociation constants of BPs. These results suggest that there are substantial differences among BPs in their binding to hydroxyapatite. From the cellular aspect of my study, I present evidence for the anti-apoptotic effects of BPs in osteocytes and osteoblasts. However, the study of prosurvival signalling pathways involved in these cells needs to be optimised. The work described in this thesis provides novel insights into the physiological and biological mechanisms of BP action. My project has provided a better knowledge of the physicochemical properties of BPs, which are highly relevant to their differential distributions within bone, their biological potencies, and their durations of action. Additionally, the cell culture studies may provide new information on the cellular effects of BPs on osteocytes and osteoblasts.

The Oxford Unicompartmental Knee Replacement (UKR) is a commonly performed procedure, with a good clinical outcome at 15 years, however, radiolucent lines are commonly found beneath the tibial tray. With the projected increase in knee arthroplasty, particularly in younger patients, implant longevity is of paramount importance. The aim of this thesis is to understand how fixation is achieved with the Oxford UKR and how it can be improved. A histological study demonstrated that in the presence of a radiolucent line the tibial bone-cement interface is made up of a combination of direct bony contact, fibrocartilage and fibrous tissue. The radiolucency is more marked when there is more soft tissue. However in all cases there is some direct bony contact. Cemented and cementless fixation was compared in a randomised controlled study using radiostereometric analysis and fluoroscopic imaging of the interfaces. In the first year the cementless tibial component subsided on average 0.28 mm and had an increased posterior slope of 0.40°, whereas the cemented component only subsided 0.09 mm, with a 0.10° increase in slope. In the second year both components had very little further subsidence (mean<0.05 mm) and no increase in posterior slope. In the second year a single cementless tibial component subsided greater than 0.15 mm, whereas four cemented components, all with radiolucencies, subsided more than 0.15 mm. At two years the cemented components had a significantly higher prevalence of radiolucency (62% v 29%), with 24% having a complete radiolucency, whereas no cementless components had a complete radiolucency. Two designs of lateral UKR were also compared. These had a flat tibial component that predominantly transmits compressive loading, and a domed component that also transmits shear. There was a lower prevalence of radiolucency in the domed tibia (13% v 60%), even though there was a similar amount of migration as the cemented medial tibial component. In conclusion radiolucent lines, both partial and complete, are common with cemented components, and may, in part, be a result of compressive loading. They are associated with good long-term results and direct bone cement contact indicating satisfactory fixation. However, they are also associated with increased migration and soft tissue at the interface suggesting that the fixation, although satisfactory, is suboptimal. The cementless components had no complete radiolucencies and low levels of migration in the second year. This suggests that bone ingrowth and secure fixation occurs reliably, and therefore that cementless fixation may be better than cemented for the Oxford UKR.

Anteromedial osteoarthritis of the knee (AMOA) has been defined anatomically, histologically and radiologically and yet little is known about the epidemiology of the disease or the risk factors involved in the development of the disease. The broad aim of this thesis was to combine clinical insight with the utilisation of modern, large epidemiological datasets to provide information to inform better the clinical management of patients with AMOA. Specifically, the prevalence and incidence of AMOA, the time taken to progress from early disease to severe disease that may require surgical intervention, the radiological characterisation of disease and the assessment of mechanical risk factors implicit in the development of this pattern of disease are investigated. A cross-sectional study of the radiological prevalence of AMOA in a symptomatic cohort in a specialist secondary care knee clinic showed that AMOA was the commonest pattern of knee OA, present in more than 60&percnt; of symptomatic subjects. Less than 25% of subjects with AMOA presented with advanced or 'bone-on-bone' disease, emphasising the clinical importance of understanding the progression from earlier stages of disease to this advanced stage. A 20-year longitudinal radiographic study was performed on 1000 women to describe the prevalence, incidence and progression of AMOA. The prevalence of AMOA was 43&percnt; and the incidence over 20-years was 0.4. Life table analysis showed that the risk of developing advanced AMOA in a previously normal knee was 2.6&percnt;. Of those subjects with early radiological AMOA, 11&percnt; progressed to advanced 'bone-on-bone' disease within 10 years and 37% within 20 years. The role of mechanical risk factors in the development of AMOA showed that both anatomical limb and proximal tibial alignment were significantly more varus aligned in those that developed AMOA at 20-years. Assessment of the shape of the medial tibial plateau in a longitudinal MRI study showed that the angle of the upslope at the anterior aspect of the plateau was significantly increased in the group that subsequently developed AMOA. To enable AMOA to be studies in future MRI studies, the MRI description of the disease was defined. In summary, AMOA was shown to be the most common pattern of knee OA both in symptomatic surgical cohorts and in the community. The progression of the disease from an early stage to an advanced stage, which may require surgical intervention, was described for the first time. To enable better the recognition of AMOA in modern epidemiological studies, the MRI description of AMOA was defined and the clinical relevance of modern MRI was discussed. The anatomical alignment of the limb, the alignment of the proximal tibia and the morphology of the tibial plateau were all shown to have a role in the development of AMOA. Addressing these mechanical factors may provide a therapeutic surgical target for the management of patients with AMOA.

Total hip replacement (THR) is one of the most successful and most frequently performed operations. For most implants the published rate of revision at 10 years is less than 10%. However the revision rates are higher for younger and more active patients who are likely to outlive their implants. The most frequent cause of THR failure is aseptic loosening, commonly accompanied by bone loss at the implant site. THR revisions give worse functional results and fail sooner than primary THR and are complicated by this loss of bone stock. A resurfacing hip prosthesis replaces the diseased surface layer of bone and cartilage and retains the majority of the femoral head. The stress distribution in the proximal femur is closer to that in an intact hip. A conservative resurfacing prosthesis will present the surgeon with no greater problems at revision than encountered at primary conventional 11-JR. Early designs of resurfacing prosthesis conserved femoral bone stock at the expense of acetabular bone. Revision rates were high and while some failures were caused by avascular necrosis and femoral neck fracture the predominant cause was acetabular loosening. The design of a bone conserving prosthesis requires knowledge of the shape of the bony surfaces of the hip joint. A survey of the morphology of the acetabulum showed a wide variation in shape. While early resurfacing designs had hemispherical acetabular cups the bony surface is less than hemispherical. The morphology and desired range of hip motion constrain prosthesis thickness and shape. A novel resurfacing design using a polyacetal femoral component and an UHMWPE acetabular component is proposed. This bearing combination has a lower volumetric wear rate than an equivalent Co-Cr on UHWMPE bearing. Computer modelling of the resurfacing concept showed that lower moduli materials reduced stress shielding and distributed implant-bone interface stresses more evenly. Mechanical testing of polyacetal following immersion in Ringer's solution showed substantial decreases in Young's modulus while strength was unaffected.