Aims. While a centralized system for the care of patients with a sarcoma has been advocated for decades, regional variations in survival remain unclear. The aim of this study was to investigate regional variations in survival and the impact of national policies in patients with a soft-tissue sarcoma (STS) in the UK. Methods. The study included 1,775 patients with a STS who were referred to a tertiary sarcoma centre. The geographical variations in survival were evaluated according to the periods before and after the issue of guidance by the National Institute for Health and Care Excellence (NICE) in 2006 and the relevant evolution of regional management. Results. There had been a significant difference in survival between patients referred from the North East, North West, East Midlands, West Midlands, South West, and Wales in the pre-NICE era (five-year disease-specific survival (DSS); South West, 74% vs North East, 47% (p = 0.045) or West Midlands, 54% (p = 0.049)), which was most evident for patients with a high-grade STS. However, this variation disappeared in the post-NICE era, in which the overall DSS for high-grade STS improved from 47% to 68% at five years (p < 0.001). Variation in the size of the tumour closely correlated with the variation in DSS, and the overall size of the tumour and incidence of metastasis at the time of diagnosis also decreased after the national policies were issued. Conclusion. The survival of patients with a STS improved and regional variation corrected after the introduction of national policies, as a result of a decreasing size of tumour and incidence of metastasis at the time of diagnosis, particularly in patients with a high-grade STS. This highlights the positive impact of national guidelines on regional variation in the presentation, management, and outcome in patients with a STS. Cite this article: Bone Joint J 2021;103-B(9):1541–1549

Hip arthroscopy (HA) and pelvic osteotomy (PO) are surgical procedures used to treat a variety of hip pathology affecting young adults, including femoroacetabular impingement and hip dysplasia respectively. This study aimed to investigate the trends and regional variation in the provision of HA and PO across England from 2010 to 2023 to inform healthcare resource allocation. We analysed the National Hospital Episode Statistics database for all HA and PO procedures in NHS England using specific OPCS-4 codes: HA: ‘W83+Z843’ or ‘W84+Z843’; PO: ‘X222+Z75’. We collected patient demographics, age, sex, and region of treatment. We performed descriptive and regression analyses to evaluate temporal trends in PO volume, age, sex and regional variation. 22,401 HAs and 1,348 POs were recorded between 2010 and 2023. The annual number of HAs declined by 28.4%, whilst the number of POs increased by 64% (p<0.001). Significantly more females underwent PO vs HA (90% vs 61.3%) and were older than males undergoing the same procedure (PO: 29.0±8.7 vs 25.8±9.2 years; HA: 36.8±12.0 years vs 35.8±11.2 years, p<0.001). For HA, the mean age of both sexes decreased by 3.3 and 2.9 years respectively (p<0.001), whereas the age of PO patients did not change significantly over the study period. There were significant regional variations with a mean incidence of 1.60/100,00 for HA (ranging from 0.70–2.66 per 100,000) and 0.43/100,000 for PO (ranging from 0.08–2.07 per 100,000). We have observed a decline in HA volume in England, likely due to improved patient selection and the impact of COVID-19, whilst PO volume has significantly increased, with regional variation persisting for both procedures. These trends highlight the need for equitable HA and PO access to improve patient outcomes and call for strategic healthcare planning and resource allocation to reduce disparities and improve training opportunities

The purpose of this study was to assess the regional variation in the incidence of hip fractures in patients over 65 years. in New Zealand. Data from the National Minimum Data Set (NMDS) for hip fractures from 1 July 1998 to 31 June 2000 was obtained. The data was divided into 21 District Health Board (DHB) regions by mapping from domicile code to DHB. Population of interest as at 30 June 1999 was estimated on the basis of previous census in 1996. The incidence of hip fracture per 100,000 for each region was calculated and divided into age and sex cohorts. There is a significant difference between DHBs in the sex and age adjusted incidence of hip fractures. The rates ranged from 556 per 100,000 to 838 per 100,00. As expected there was a higher fracture rate in women and the fracture rate increased with age. There was a weak correlation with sunshine hours (p=0.029) with increasing fracture incidence as sunshine hours decrease. This study demonstrates a large variation in the incidence of hip fractures per DHB region. The cause for this is unclear, but the cost implications are significant. DHB’s with a high incidence of hip fractures in their region may wish to investigate strategies for reducing the incidence

The Nottingham Hip Fracture Score (NHFS) was developed to assess the risk of death following a fracture of the hip, based on pre-operative patient characteristics. We performed an independent validation of the NHFS, assessed the degree of geographical variation that exists between different units within the United Kingdom and attempted to define a NHFS level that is associated with high risk of mortality.

The NHFS was calculated retrospectively for consecutive patients presenting with a fracture of the hip to two hospitals in England. The observed 30-day mortality for each NHFS cohort was compared with that predicted by the NHFS using the Hosmer–Lemeshow test. The distribution of NHFS in the observed group was compared with data from other hospitals in the United Kingdom. The proportion of patients identified as high risk and the mortality within the high risk group were assessed for groups defined using different thresholds for the NHFS.

In all 1079 hip fractures were included in the analysis, with a mean age of 83 years (60 to 105), 284 (26%) male. Overall 30-day mortality was 7.3%. The NHFS was a significant predictor of 30-day mortality. Statistically significant differences in the distribution of the NHFS were present between different units in England (p < 0.001). A NHFS ≥ 6 appears to be an appropriate cut-point to identify patients at high risk of mortality following a fracture of the hip.

Cite this article: Bone Joint J 2015;96-B:100–3.

Aims

The current study aimed to compare robotic arm-assisted (RA-THA), computer-assisted (CA-THA), and manual (M-THA) total hip arthroplasty regarding in-hospital metrics including length of stay (LOS), discharge disposition, in-hospital complications, and cost of RA-THA versus M-THA and CA-THA versus M-THA, as well as trends in use and uptake over a ten-year period, and future projections of uptake and use of RA-THA and CA-THA.

The need to accurately forecast the injury burden has never been higher. With an aging, ever expanding trauma population and less than half of the beds available compared to 1990, the National Health Service (NHS) is stretched to breaking point. 1,2. . We utilised a dataset of 22,585 trauma patients across the four countries of the United Kingdom (UK) admitted to 83 hospitals between 22/08/22 – 16/10/22 to determine whether it is possible to predict the proportionality of injuries treated operatively within orthopaedic departments based on their number of Neck of Femur fracture (NOF) patients. More operations were performed for elderly hip fractures alone than for the combined totals of the next four most common fractures: ankle, distal radius, tibial shaft and forearm (6387 vs 5922). Conversely, 10 out of the 13 fracture types were not encountered by at least one hospital and 93% of hospitals encountered less than 2 fractures of a certain type. 60% trauma is treated within Trauma Units (TUs) however, per unit, Major Trauma Centres (MTCs) treat approximately 43% more patients. After excluding NOF, lower limb fractures accounted for approximately 57% of fractures in all countries and ankle and distal radius fracture combined comprised more than 50% in 74% of regions. The number of hip fractures seen on average by an individual unit remains relatively consistent as does the regional variation of any given fracture; resultantly, it is possible to predict injury proportionality based off a unit's hip fracture numbers. This powerful tool could transform both resource allocation and recruitment

Meniscal injuries affect over 1.5 million people across Europe and the USA annually. Injury greatly reduces knee joint mobility and quality of life and frequently leads to the development of osteoarthritis. Tissue engineered strategies have emerged in response to a lack of viable treatments for meniscal pathologies. However, to date, constructs mimicking the structural and functional organisation of native tissue, whilst promoting deposition of new extracellular matrix, remains a bottleneck in meniscal repair. 3D bioprinting allows for deposition and patterning of biological materials with high spatial resolution. This project aims to develop a biomimetic 3D bioprinted meniscal substitute. Meniscal tissue was characterised to effectively inform the design of biomaterials for bioprinting constructs with appropriate structural and functional properties. Histology, gene expression and mass spectrometry were performed on native tissue to investigate tissue architecture, matrix components, cell populations and protein expression regionally across the meniscus. 3D laser scanning and magnetic resonance imaging were employed to acquire the external geometrical information prior to fabrication of a 3D printed meniscus. Bioink suitability was investigated through regional meniscal cell encapsulation in blended hydrogels, with the incorporation of growth factors and assessed for their suitability through rheology, scanning electron microscopy, histology and gene expression analysis. Meniscal tissue characterisation revealed regional variations in matrix compositions, cellular populations and protein expression. The process of imaging through to 3D printing highlighted the capability of producing a construct that accurately replicated meniscal geometries. Regional meniscal cell encapsulation into hydrogels revealed a recovery in cell phenotype, with the incorporation of growth factors into the bioink's stimulating cellular re-differentiation and improved zonal functionality. Meniscus biofabrication highlights the potential to print patient specific, customisable meniscal implants. Achieving zonally distinct variations in cell and matrix deposition highlights the ability to fabricate a highly complex tissue engineered construct. Acknowledgements: This work was undertaken as part of the UK Research and Innovation (UKRI)-funded CDT in Advanced Biomedical Materials

Introduction. The management of open or unstable ankle and distal tibial fractures pose many challenges. In certain situations, hindfoot nailing (HFN) is indicated, however this depends on surgeon preference and regional variations exist. This study sought to establish the current management and outcomes of complex ankle fractures in the UK. Methods. A National collaborative study in affiliation with BOTA was conducted and data retrospectively collected between January 1. st. – June 30. th. 2019. Adult patients with open and closed complex ankle fractures (AO43/44) were included. Complex fractures included the following patient characteristics: diabetes ± neuropathy, rheumatoid arthritis, alcoholism, polytrauma and cognitive impairment. We obtained data on fixation choice and patient outcomes. Institutional approval was obtained by all centres, and statistical analysis was performed including propensity matching. Results. Fifty-six centres provided data for 1360 patients. The average age of the cohort was 53.9 years ±19 (SD) with a male/female ratio of 1:1.3. 920 patients were ASA 1/2, 440 were ASA 3/4; 316 had diabetes, and 275 were open fractures. Most fractures were AO44 (71.2%) and more commonly associated with diabetes (P<0.001), alcoholism (P<0.007), open (P<0.013), and advanced age (55.7 vs. 46.3). 1227 patients underwent primary-fixation (111 HFN), with the remainder treated with external-fixation (84 definitive). Of the 111 HFN, 35% underwent primary fusion. Wound complication and thromboembolic rates were greater in the HFN group compared to ORIF groups (P<0.003), being more evident in the HFN group with primary fusion even after propensity matching. However, 1081 patients were non-weightbearing post-op contrary to the BOAST guidance. Conclusion. This is the first National collaborative audit of complex ankle fractures. Hindfoot nails were used in 9% of patients and we observed more complications in this group when compared to other cohorts. Despite BOAST guidance, only 21% of patients undergoing operative management were instructed to fully weightbear post-operatively

Abstract. Objectives. The need to accurately forecast the injury burden has never been higher. With an aging, ever expanding trauma population and less than half of the beds available compared to 1990, the National Health Service (NHS) is stretched to breaking point1,2. Resultantly, we aimed to determine whether it is possible to predict the proportionality of injuries treated operatively within orthopaedic departments based on their number of Neck of Femur fracture (NOF) patients reported both in our study and the National Hip Fracture Database (NHFD). Methods. We utilised the ORthopaedic trauma hospital outcomes - Patient operative delays (ORTHOPOD) dataset of 22,585 trauma patients across the four countries of the United Kingdom (UK) admitted to 83 hospitals between 22/08/22 – 16/10/22. This dataset had two arms: arm one was assessing the caseload and theatre capacity, arm two assessed the patient, injury and management demographics. Results. Our results complied with the data reported to the NHFD in over 80% of cases for both the 2022 and five-year average reported numbers. More operations were performed for elderly hip fractures alone than for the combined totals of the next four most common fractures: ankle, distal radius, tibial shaft and forearm (6387 vs 5922). Conversely, 10 out of the 13 fracture types were not encountered by at least one hospital and 93% of hospitals encountered less than 2 fractures of a certain type.60% of trauma is treated within Trauma Units (TUs) however, per unit, Major Trauma Centres (MTCs) treat approximately 43% more patients. Similarly, 11 out of the 14 fracture types examined presented more frequently to a MTC however 3 of the most common fractures had a preponderance for TUs (elderly hip, distal radius and forearm fractures). After excluding NOF, lower limb fractures accounted for approximately 57% of fractures in all countries and ankle and distal radius fracture combined comprised more than 50% in 74% of regions. There were few outliers across the study regarding number of fractures treated by a hospital with tibial shaft fractures demonstrating the highest number of outliers with 4. Conclusions. The number of hip fractures seen on average by an individual unit remains relatively consistent as does the regional variation of any given fracture; resultantly, it is possible to predict injury proportionality based off a unit's hip fracture numbers. This powerful tool could transform both resource allocation and recruitment. Declaration of Interest. (b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project

Objectives. We wanted to investigate regional variations in the organisms reported to be causing peri-prosthetic infections and to report on prophylaxis regimens currently in use across England. Methods. Analysis of data routinely collected by Public Health England’s (PHE) national surgical site infection database on elective primary hip and knee arthroplasty procedures between April 2010 and March 2013 to investigate regional variations in causative organisms. A separate national survey of 145 hospital Trusts (groups of hospitals under local management) in England routinely performing primary hip and/or knee arthroplasty was carried out by standard email questionnaire. Results. Analysis of 189 858 elective primary hip and knee arthroplasty procedures and 1116 surgical site infections found statistically significant variations for some causative organism between regions. There was a 100% response rate to the prophylaxis questionnaire that showed substantial variation between individual trust guidelines. A number of regimens currently in use are inconsistent with the best available evidence. Conclusions. The approach towards antibiotic prophylaxis in elective arthroplasty nationwide reveals substantial variation without clear justification. Only seven causative organisms are responsible for 89% of infections affecting primary hip and knee arthroplasty, which cannot justify such widespread variation between prophylactic antibiotic policies. Cite this article: Bone Joint Res 2015;4:181–189

Worldwide, most spine imaging is either “inappropriate” or “probably inappropriate”. The Choosing Wisely recommendation is “Do not perform imaging for lower back pain unless red flags are present.” There is currently no detailed breakdown of lower back pain diagnostic imaging performed in New Brunswick (NB) to inform future directions. A registry of spine imaging performed in NB from 2011-2019 inclusive (n=410,000) was transferred to the secure platform of the NB Institute for Data, Training and Research (NB-IRDT). The pseudonymized data included linkable institute identifiers derived from an obfuscated Medicare number, as well as information on type of imaging, location of imaging, and date of imaging. The transferred data did not include the radiology report or the test requisition. We included all lumbar, thoracic, and complete spine images. We excluded imaging related to the cervical spine, surgical or other procedures, out-of-province patients and imaging of patients under 19 years. We verified categories of X-ray, Computed Tomography (CT), and Magnetic Resonance Imaging (MRI). Red flags were identified by ICD-10 code-related criteria set out by the Canadian Institute for Health Information. We derived annual age- and sex-standardized rates of spine imaging per 100,000 population and examined regional variations in these rates in NB's two Regional Health Authorities (RHA-A and RHA-B). Age- and sex-standardized rates were derived for individuals with/without red flag conditions and by type of imaging. Healthcare utilization trends were reflected in hospital admissions and physician visits 2 years pre- and post-imaging. Rurality and socioeconomic status were derived using patients’ residences and income quintiles, respectively. Overall spine imaging rates in NB decreased between 2012 and 2019 by about 20% to 7,885 images per 100,000 people per year. This value may be higher than the Canadian average. Females had 23% higher average imaging rate than males. RHA-A had a 45% higher imaging rate than RHA-B. Imaging for red flag conditions accounted for about 20% of all imaging. X-rays imaging accounted for 67% and 75% of all imaging for RHA-A and RHA-B respectively. The proportions were 20% and 8% for CT and 13% and 17% for MRI. Two-year hospitalization rates and rates of physician visits were higher post-imaging. Females had higher age-standardized hospitalization and physician-visit rates, but the magnitude of increase was higher for males. Individuals with red flag conditions were associated with increased physician visits, regardless of the actual reason for the visit. Imaging rates were higher for rural than urban patients by about 26%. Individuals in the lowest income quintiles had higher imaging rates than those in the highest income quintiles. Physicians in RHA-A consistently ordered more images than their counterparts at RHA-B. We linked spine imaging data with population demographic data to look for variations in lumbar spine imaging patterns. In NB, as in other jurisdictions, imaging tests of the spine are occurring in large numbers. We determined that patterns of imaging far exceed the numbers expected for ‘red flag’ situations. Our findings will inform a focused approach in groups of interest. Implementing high value care recommendations pre-imaging ought to replace low-value routine imaging

Total Hip Replacements (THR) and Hip Hemiarthroplasties (HA) are both successful and common orthopaedic procedures. Dislocation is a well-recognised complication carrying significant morbidity and, in some cases, increased mortality risks. We define prosthetic hip dislocations (PHDs) to include both THRs and HAs. Prosthetic Hip Dislocations (PHDs) are a common acute admission yet there are no published guidelines or consensus on management following reduction. A retrospective audit was undertaken by the North West Orthopaedic Research Collaborative (NWORC) between January 2019 and July 2019. A questionnaire was used to capture the management of each dislocation episode presenting to 11 Hospital trusts. The study was registered as a Quality Improvement (QI) project at each site. Data regarding the surgical management physiotherapy input, ongoing care and further management plans were recorded. A total of 183 patients with 229 dislocations were submitted for initial analysis (171 THRs, 10 HAs, 2 PFRs). Female to male ratio was 2:1 with mean age of 76.7 years. Average time to first dislocation was 8.1 years. 61.1% were first or second time dislocators and 38.9% presented with 3 or more dislocations. Initial reductions were predominantly attempted in theatre (96.5%, n=221) with only 3.5% (n=8) attempted in the emergency department. In theatre 89% (n=201) were reduced closed. There was no plan for revision surgery in 70.6% cases with no difference seen between patients with >=3 dislocations and <=2 dislocations. Of the patients with a revision plan, 71% of these were performed or planned locally. The high number of patients with 3 or more dislocations and the lack of plans for definitive interventions in the majority of cases highlights the significant variation in the management of this complex group of patients. This variation in the quality of care increases the burden on the National Health Service through repeat hospital episodes. We aim to roll out this study nationally to assess regional variations and ultimately make the case for national guidance on the management of prosthetic hip dislocations

Aims. Accumulated evidence indicates that local cell origins may ingrain differences in the phenotypic activity of human osteoblasts. We hypothesized that these differences may also exist in osteoblasts harvested from the same bone type at periarticular sites, including those adjacent to the fixation sites for total joint implant components. Methods. Human osteoblasts were obtained from the acetabulum and femoral neck of seven patients undergoing total hip arthroplasty (THA) and from the femoral and tibial cuts of six patients undergoing total knee arthroplasty (TKA). Osteoblasts were extracted from the usually discarded bone via enzyme digestion, characterized by flow cytometry, and cultured to passage three before measurement of metabolic activity, collagen production, alkaline phosphatase (ALP) expression, and mineralization. Results. Osteoblasts from the acetabulum showed lower proliferation (p = 0.034), cumulative collagen release (p < 0.001), and ALP expression (p = 0.009), and produced less mineral (p = 0.006) than those from the femoral neck. Osteoblasts from the tibia produced significantly less collagen (p = 0.021) and showed lower ALP expression than those from the distal femur. Conclusion. We have demonstrated for the first time an anatomical regional variation in the biological behaviours of osteoblasts on either side of the hip and knee joint. The lower osteoblast proliferation, matrix production, and mineralization from the acetabulum compared to those from the proximal femur may be reflected in differences in bone formation and implant fixation at these sites. Cite this article: Bone Joint Res 2021;10(9):611–618

Hip fractures in elderly patients are managed at both major trauma centers (MTC) and trauma units (TU). Previous evidence has demonstrated the importance of early surgery to reduce the morbidity and mortality related to the injury. The aim of this study is to compare the ‘time to theatre' and ‘30 day mortality' in TUs versus MTC in UK. A retrospective review of prospectively collected data on NHFD was performed. The average ‘time to theatre' in hours and ‘30 day mortality' of all hospitals were analysed between January and December 2018. Further subgroup analysis was done to check for any regional variations; in each instance a Shapiro-Wilk test was used to check for normal distribution, followed by a one-way ANOVA with a Tukey's post hoc test. Data from 158 hospitals in England (ENG), Wales (WAL) and Northern Ireland (NI) were used; 18 of which were MTC. There were 57,936 operative cases in TUs and 8606 in MTC's. The mean time (hours) to surgery from presentation was 32.51 and 32.64 for TUs and MTC respectively (p=0.513). There was no significant difference in ‘30 day mortality' (p=0.635) between TUs (6%) and 5.7% MTC's (5.7%), MTC's and TUs in ENG, WAL and NI (p=0.555), and MTC and WAL, NI and the different regions of ENG (p=0.209). A significant difference was observed, between the regional practice for TUs versus MTC's in ENG, WAL and NI (p=0.001) and between MTC's and TUs in WAL, NI and the different regions of ENG (p=0.001), with patients waiting significantly longer in NI for their procedure (mean=60.25 hours, p=0.001). There was no significant difference in time to surgery or 30 day mortality between TUs and MTC's, demonstrating comparable hip fracture care, despite MTCs need to prioritise more serious injuries

5207 patients treated for a calcaneous fracture in Ontario between 1993–1999 were identified from population datasets and were reviewed to evaluate regional practice variation and complication rates for operatively and non-operatively managed calcaneous fractures. There was considerable geographic variation in treatment. Individuals in some parts of Ontario were almost eight times more likely to receive operative treatment than others. The majority of calcaneous fractures in Ontario are treated non-operatively, however the large observed practice variation suggests that there is disagreement among treating clinicians. Primary subtalar fusion has a high risk of post-operative infection and should therefore be considered very cautiously. The purpose of this study was to evaluate regional practice variation and complication rates for operatively and non-operatively managed calcaneous fractures. The majority of calcaneous fractures in Ontario are treated non-operatively, however the large observed practice variation suggests that there is disagreement among treating clinicians. Primary subtalar fusion has a high risk of post-operative infection and should therefore be considered very cautiously. Given the observed regional variation in management of calcaneous fractures more work needs to be done to address this issue. 5207 fractures of the calcaneous in Ontario between 1993–1999were identified from population datasets. Regional variations in treatment and complication rates were computed. Multiple linear regression was used to identify factors associated with complications. There was considerable geographic variation in treatment. Individuals in some parts of Ontario were almost eight times more likely to receive operative treatment than others. General surgeons or general practitioners definitively treated 30% of patients (almost all closed). Overall rate of complications was low, however there was a 13.4 percent infection rate following immediate subtalar fusion. Infection was 5.3% following ORIF and 0.6% following closed treatment. Infection risk was increased in multiple trauma patients and those with open fractures. Subsequent subtalar fusion rates (within the study period) were higher in multiple trauma patients, but were not associated with treatment (open or closed). Amputation was 22.5 times more likely following open calcaneous fractures but the overall amputation rate was only 0.17%. No relationship between surgeon experience and the rate of complications following operative treatment was identified

Summary Statement. This study assesses oxidation, mechanical behavior and revision reasons of 2. nd. generation HXLPE used in total hip and knee arthroplasty. While oxidation was low for both X3 and E1 HXLPEs, oxidative regional variations were detected in the sequentially annealed cohort. Introduction. First generation highly crosslinked polyethylenes (HXPLEs) have proven successful in lowering both penetration and osteolysis rates. However, 1. st. generation annealing and remelting thermal stabilization have been associated with in vivo oxidation or reduced mechanical properties. Thus, 2. nd. generation HXLPEs were developed to improve oxidative stability while still maintaining material properties. Little is known about the in vivo clinical failure modes of these 2. nd. generation HLXPEs. The purpose of this study was to assess the revision reasons, wear, oxidative stability, and mechanical behavior of retrieved sequentially annealed Vitamin E diffused HXLPE in THA and TKA. Methods. 251 2. nd. Generation HXLPE hip and knee components were consecutively retrieved during revision surgeries and continuously analyzed in a prospective, IRB approved, multicenter study. 123 acetabular liners (Implanted 1.2y; Range 0–5.0y) and 117 tibial inserts (Implanted 1.6y; Range 0–5.8y) were highly crosslinked and annealed in 3 sequential steps (X3). Five acetabular liners (Implanted 0.6y; Range 0–2.0y) and six tibial inserts (Implanted 1.3y; Range 0.5–1.8y) were diffused with Vitamin E (E1). Patient information was collected from medical records. Linear penetration of liners was measured using a calibrated digital micrometer (accuracy: 0.001 mm). Surface damage of tibial components was assessed using the Hood method. Thin sections were taken from the acetabular liners (along the superior/inferior axis) and the tibial components (along the medial condyle and central spine) for oxidation analysis and analyzed according to ASTM 2102. Mechanical behavior was assessed via the small punch test (ASTM 2183). Results. The liners and tibial components fabricated from both HXLPEs were revised predominantly for loosening, instability, and infection. The average penetration rate for the Sequentially Annealed group was low (PR=0.045mm/yr). Pitting, scratching and burnishing were the predominant damage mechanisms of the tibial inserts within both material groups, with no evidence of delamination. Oxidation indices were low (Mean OI≤0.3) and similar between liners and inserts of the Sequentially Annealed components at the bearing and backside surface (p≥0.15). Oxidation was positively correlated with implantation time at the bearing surface of the Sequentially Annealed groups (Rho>0.29, p<0.005). The Ultimate Load of the Sequentially Annealed acetabular liners was statistically higher than the tibial components (p<0.001), however the mean difference was minimal (∼6N). Discussion. This study evaluated the properties of 2. nd. generation HXLPEs used in THA and TKA. Sequentially Annealed liners had penetration rates comparable with 1. st. generation HXLPEs. While oxidation was low for both sequentially annealed and Vitamin E HXLPEs, we were able to detect regional variations in the oxidative in the sequentially annealed cohort. Longer-term retrievals are necessary to fully assess the oxidative stability of Vitamin E diffused HXLPE used in TKA and THA

This study examined the regional variations of cortical and cancellous bone density present in superiorly eroded glenoids. It is hypothesized that eroded regions will contain denser bone in response to localized stress. The shift in natural joint articulation may also cause bone resorption in areas opposite the erosion site. Clinical CT scans were obtained for 32 shoulders (10m/22f, mean age 72.9yrs, 56–88yrs) classified as having E2-type glenoid erosion. The glenoid was divided into four measurement regions - anterior, inferior, posterior, and superior - as well as five depth regions. Depth regions were segmented in two-millimeter increments from zero to 10 millimeters, beginning at the center of the glenoid surface. A repeated-measures multiple analysis of variance (RM-MANOVA) was performed using SPSS statistical software to look for differences and interactions between mean densities in each depth, quadrant, and between genders. A second RM-MANOVA was performed to examine effects of gender and quadrant on cortical to cancellous bone volume ratios. Significance was set at p < 0 .05. Quadrant and depth variables showed significant multivariate main effects (p 0.147 respectively). Quadrant, depth, and their interaction showed significant univariate main effects for cortical bone (p≤0.001) and cancellous bone (p < 0 .001). The lowest bone density was found to be in the inferior quadrant for cancellous bone (307±50 HU, p < 0 .001). The superior quadrant contained the highest mean density for cortical bone (895±97 HU), however it was only significantly different than in the posterior quadrant (865±97 HU, p=0.022). As for depth, it was found that cortical bone is most dense at the glenoid surface (zero to two millimeters, 892±91 HU) when compared to bone at two to eight millimeters in depth (p < 0 .02). Cancellous bone was also most dense at the surface (352±51 HU), but only compared to the eight to 10 millimeters depth (p=0.005). Cancellous bone density was found to decrease with increasing depth. For cortical-to-cancellous bone volume ratios, the inferior quadrant (0.37±0.28) had a significantly lower ratio than all other quadrants (p < 0 .001). The superoposterior region of the glenoid was found to have denser cancellous bone and a high ratio of cortical to cancellous bone, likely due to decreased formation of cancellous bone and increased formation of cortical bone, in response to localized stresses. The inferior quadrant was found to have the least dense cortical and cancellous bone, and the lowest volume of cortical bone relative to cancellous bone. Once again, this is likely due to reduction in microstrain responsible for bone adaptation via Wolff's law. The density values found in this study generally agree with the range of values found in previous studies of normal and arthritic glenoids. An important limitation of this study is the sizing of measurement regions. For a patient with a smaller glenoid, a depth measurement of two millimeters may represent a larger portion of the overall glenoid vault. Segments could be scaled for each patient based on a percentage of each individual's glenoid size

Three 3mm transverse slices were sectioned from the distal cancellous region of seven fresh-frozen cadaveric humerii. Each slice was marked with a 3x3mm grid, and subjected to compressive testing using a flat cylindrical indenter (1.6mm diameter). Indentation modulus and strength were calculated for each site, and pooled into nine anatomically-defined regions. The most distal slice had higher moduli values (p< 0.05), and the posterior capitellar region had lower moduli values (p< 0.05). There were no slice or regional differences in strength. This suggests that surgical procedures requiring cancellous fixation utilize the most distal aspect of the humerus while avoiding the posterior capitellum. To quantify the indentation strength and modulus of distal humeral cancellous bone, and identify any regional variations. Cancellous bone modulus in the distal humerus decreases from distal to proximal. The posterior capitellum has a lower modulus than the other regions of the distal humerus. The influence of slice depth emphasizes the importance of minimizing the amount of bone removed during prosthetic replacement. Regional variations in modulus suggest that the posterior capitellum should be avoided during fixation of implants or placement of screws. Three 3mm transverse cancellous bone slices obtained from the distal end of each of seven fresh-frozen cadaveric specimens were subjected to compressive testing using a materials testing machine with a 1.6mm flat cylindrical indenter. Testing was performed in a 3x3mm grid. The indentation modulus and local strength were calculated for each test site, and then averaged into nine regions defined by the capitellum, medial and lateral trochlea, and anterior, central and posterior sections for each slice. Mean modulus was found to be 309.8±242.0 MPa (range: 2.9–1041.7 MPa). Yield strength averaged 4.4±2.5 MPa (range: 0.6–16.3 MPa). The highest modulus was found in the distal-most slice (p< 0.05). The lowest modulus region was the posterior capitellum (p< 0.05). There were no differences in strength between slices or across the nine regions. A comparison with proximal tibial cancellous bone properties suggests the distal humerus may carry loads approaching 30% of those at the knee, assuming that bone adapts to stress magnitudes. Funding: Natural Sciences and Engineering Research Council; University of Western Ontario

Post-traumatic arthritis is a frequent consequence of articular fracture. The mechanisms leading to its development after such injuries have not been clearly delineated. A potential contributing factor is decreased viability of the articular chondrocytes. The object of this study was to characterise the regional variation in the viability of chondrocytes following joint trauma. A total of 29 osteochondral fragments from traumatic injuries to joints that could not be used in articular reconstruction were analysed for cell viability using the fluorescence live/dead assay and for apoptosis employing the TUNEL assay, and compared with cadaver control fragments. Chondrocyte death and apoptosis were significantly greater along the edge of the fracture and in the superficial zone of the osteochondral fragments. The middle and deep zones demonstrated significantly higher viability of the chondrocytes. These findings indicate the presence of both necrotic and apoptotic chondrocytes after joint injury and may provide further insight into the role of chondrocyte death in post-traumatic arthritis

In June 2012 the Orthopaedic Speciality Advisory of the Joint Committee on Surgical Training defined ‘minimum indicative numbers’ that trainees would have to meet before completion of specialist training. It has been speculated that regions have varied in their ability to provide operative opportunities to their trainees. This study aims to test the hypothesis that there are regional differences in operative training experience. The eLogbook database was interrogated for cases over a 12 month period from 7 August 2013 to 5 August 2015. Within each region, the mean of the cases registered by orthopaedic trainees in each year of training during the study period was calculated and summed to give a representative surgical experience for the years ST3-8. First surgeon only cases were analysed for 11 index procedures in 30 T&O rotations. Considerable variation in training existed across rotations. In three index procedures, including DHS, no rotation achieved the minimum indicative number required. All rotations achieved the minimum indicative number of external fixator applications. This study proves the extent of the significant regional variation in surgical training in Trauma and Orthopaedics in the UK and raises concerns regarding the volume of operative training currently achieved