Introduction. Up to 60% of total hip arthroplasties (THA) in Asian populations arise from avascular necrosis (AVN), a bone disease that can lead to femoral head collapse. Current diagnostic methods to classify AVN have poor reproducibility and are not reliable in assessing the fracture risk. Femoral heads with an immediate fracture risk should be treated with a THA, conservative treatments are only successful in some cases and cause unnecessary patient suffering if used inappropriately. There is potential to improve the assessment of the fracture risk by using a combination of density-calibrated computed tomographic (QCT) imaging and engineering beam theory. The aim of this study was to validate the novel fracture prediction method against in-vitro compression tests on a series of six human femur specimens. Methods. Six femoral heads from six subjects were tested, a subset (n=3) included a hole drilled into the subchondral area of the femoral head via the femoral neck (University of Leeds, ethical approval MEEC13-002). The simulated lesions provided a method to validate the fracture prediction model with respect of AVN. The femoral heads were then modelled by a beam loaded with a single joint contact load. Material properties were assigned to the beam model from QCT-scans by using a density-modulus relationship. The maximum joint loading at which each bone cross-section was likely to fracture was calculated using a strain based failure criterion. Based on the predicted fracture loads, all six femoral heads (validation set) were classified into two groups, high fracture risk and low fracture risk (Figure 1). Beam theory did not allow for an accurate fracture load to be found because of the geometry of the femoral head. Therefore the predicted fracture loads of each of the six femoral heads was compared to the mean fracture load from twelve previously analysed human femoral heads (reference set) without lesions. The six cemented femurs were compression tested until failure. The subjects with a higher fracture risk were identified using both the experimental and beam tool outputs. Results. The computational tool correctly identified all femoral head samples which fractured at a significantly low load in-vitro (Figure 2). Both samples with a low experimental fracture load had an induced lesion in the subchondral area (Figure 3). Discussion. This study confirmed findings of a previous verification study on a disease models made from porcine femoral heads (Preutenborbeck et al. I-CORS2016). It demonstrated that fracture prediction based on beam theory is a viable tool to predict fracture. The tests confirmed that samples with a lesion in the weight bearing area were more likely to fracture at a low load however not all samples with a lesion fractured with a low load experimentally, indicating that a lesion alone is not a sufficient factor to predict fracture. The developed tool takes both structural and material properties into account when predicting the fracture risk. Therefore it might be superior to current diagnostic methods in this respect and it has the added advantage of being largely automated and therefore removing the majority of user bias. For any figures or tables, please contact the authors directly

Advances in cancer therapy have prolonged patient survival even in the presence of disseminated disease and an increasing number of cancer patients are living with metastatic bone disease (MBD). The proximal femur is the most common long bone involved in MBD and pathologic fractures of the femur are associated with significant morbidity, mortality and loss of quality of life (QoL). Successful prophylactic surgery for an impending fracture of the proximal femur has been shown in multiple cohort studies to result in longer survival, preserved mobility, lower transfusion rates and shorter post-operative hospital stays. However, there is currently no optimal method to predict a pathologic fracture. The most well-known tool is Mirel's criteria, established in 1989 and is limited from guiding clinical practice due to poor specificity and sensitivity. The ideal clinical decision support tool will be of the highest sensitivity and specificity, non-invasive, generalizable to all patients, and not a burden on hospital resources or the patient's time. Our research uses novel machine learning techniques to develop a model to fill this considerable gap in the treatment pathway of MBD of the femur. The goal of our study is to train a convolutional neural network (CNN) to predict fracture risk when metastatic bone disease is present in the proximal femur. Our fracture risk prediction tool was developed by analysis of prospectively collected data of consecutive MBD patients presenting from 2009–2016. Patients with primary bone tumors, pathologic fractures at initial presentation, and hematologic malignancies were excluded. A total of 546 patients comprising 114 pathologic fractures were included. Every patient had at least one Anterior-Posterior X-ray and clinical data including patient demographics, Mirel's criteria, tumor biology, all previous radiation and chemotherapy received, multiple pain and function scores, medications and time to fracture or time to death. We have trained a convolutional neural network (CNN) with AP X-ray images of 546 patients with metastatic bone disease of the proximal femur. The digital X-ray data is converted into a matrix representing the color information at each pixel. Our CNN contains five convolutional layers, a fully connected layers of 512 units and a final output layer. As the information passes through successive levels of the network, higher level features are abstracted from the data. The model converges on two fully connected deep neural network layers that output the risk of fracture. This prediction is compared to the true outcome, and any errors are back-propagated through the network to accordingly adjust the weights between connections, until overall prediction accuracy is optimized. Methods to improve learning included using stochastic gradient descent with a learning rate of 0.01 and a momentum rate of 0.9. We used average classification accuracy and the average F1 score across five test sets to measure model performance. We compute F1 = 2 x (precision x recall)/(precision + recall). F1 is a measure of a model's accuracy in binary classification, in our case, whether a lesion would result in pathologic fracture or not. Our model achieved 88.2% accuracy in predicting fracture risk across five-fold cross validation testing. The F1 statistic is 0.87. This is the first reported application of convolutional neural networks, a machine learning algorithm, to this important Orthopaedic problem. Our neural network model was able to achieve reasonable accuracy in classifying fracture risk of metastatic proximal femur lesions from analysis of X-rays and clinical information. Our future work will aim to externally validate this algorithm on an international cohort

Advances in cancer therapy have prolonged cancer patient survival even in the presence of disseminated disease and an increasing number of cancer patients are living with metastatic bone disease (MBD). The proximal femur is the most common long bone involved in MBD and pathologic fractures of the femur are associated with significant morbidity, mortality and loss of quality of life (QoL). Successful prophylactic surgery for an impending fracture of the proximal femur has been shown in multiple cohort studies to result in patients more likely to walk after surgery, longer survival, lower transfusion rates and shorter post-operative hospital stays. However, there is currently no optimal method to predict a pathologic fracture. The most well-known tool is Mirel's criteria, established in 1989 and is limited from guiding clinical practice due to poor specificity and sensitivity. The goal of our study is to train a convolutional neural network (CNN) to predict fracture risk when metastatic bone disease is present in the proximal femur. Our fracture risk prediction tool was developed by analysis of prospectively collected data for MBD patients (2009–2016) in order to determine which features are most commonly associated with fracture. Patients with primary bone tumors, pathologic fractures at initial presentation, and hematologic malignancies were excluded. A total of 1146 patients comprising 224 pathologic fractures were included. Every patient had at least one Anterior-Posterior X-ray. The clinical data includes patient demographics, tumor biology, all previous radiation and chemotherapy received, multiple pain and function scores, medications and time to fracture or time to death. Each of Mirel's criteria has been further subdivided and recorded for each lesion. We have trained a convolutional neural network (CNN) with X-ray images of 1146 patients with metastatic bone disease of the proximal femur. The digital X-ray data is converted into a matrix representing the color information at each pixel. Our CNN contains five convolutional layers, a fully connected layers of 512 units and a final output layer. As the information passes through successive levels of the network, higher level features are abstracted from the data. This model converges on two fully connected deep neural network layers that output the fracture risk. This prediction is compared to the true outcome, and any errors are back-propagated through the network to accordingly adjust the weights between connections. Methods to improve learning included using stochastic gradient descent with a learning rate of 0.01 and a momentum rate of 0.9. We used average classification accuracy and the average F1 score across test sets to measure model performance. We compute F1 = 2 x (precision x recall)/(precision + recall). F1 is a measure of a test's accuracy in binary classification, in our case, whether a lesion would result in pathologic fracture or not. Five-fold cross validation testing of our fully trained model revealed accurate classification for 88.2% of patients with metastatic bone disease of the proximal femur. The F1 statistic is 0.87. This represents a 24% error reduction from using Mirel's criteria alone to classify the risk of fracture in this cohort. This is the first reported application of convolutional neural networks, a machine learning algorithm, to an important Orthopaedic problem. Our neural network model was able to achieve impressive accuracy in classifying fracture risk of metastatic proximal femur lesions from analysis of X-rays and clinical information. Our future work will aim to validate this algorithm on an external cohort

The aim of this study was to investigate the risk factors, financial costs and outcomes associated with infection after hip fracture surgery.

Prospective hip fracture data from the University Hospital, Nottingham, was analysed, assessing patients with either deep or superficial wound infections admitted over a five year period.

3605 patients underwent hip fracture surgery. 2.3% of these patients developed a wound infection of which 1.2% were deep wound infections. 75% of infections were due to Staphylococcus aureus and 50% of all infections were caused by methicillin-resistant Staphylococcus aureus.

No statistically significant risk factors for the development of infection were identified in this study.

Length of stay, cost of treatment and pre-discharge mortality were all increased with deep infection. Deep wound infection increased the average length of stay from 28 days to 100 days. This quadrupled the ward costs. The mean overall hospital cost of treating a hip fracture complicated by deep wound infection was £34903 compared to £8979 fro those who did not develop infection. Pre-discharge mortality increased from 24.2% in the control group to 30% in the infected group (p<0.006).

MRSA significantly increased costs, LOS, and pre-discharge mortality compared with non-MRSA infection.

These results show the huge impact that infection after hip fracture surgery has both on mortality and hospital costs.

The widely used Fracture Risk Assessment Tool (FRAX) estimates a 10-year probability of major osteoporotic fracture (MOF) using age, sex, body mass index, and seven clinical risk factors, including prior history of fracture. Prior fracture is a binary variable in FRAX, although it is now clear that prior fractures affect future MOF risk differently depending on their recency and site. Risk of MOF is highest in the first two years following a fracture and then progressively decreases with time – this is defined as imminent risk. Therefore, the FRAX tool may underestimate true fracture risk and result in missed opportunities for earlier osteoporosis management in individuals with recent MOF. To address this, multipliers based on age, sex, and fracture type may be applied to baseline FRAX scores for patients with recent fractures, producing a more accurate prediction of both short- and long-term fracture risk. Adjusted FRAX estimates may enable earlier pharmacologic treatment and other risk reduction strategies. This study aimed to report the effect of multipliers on conventional FRAX scores in a clinical cohort of patients with recent non-hip fragility fractures. After obtaining Research Ethics Board approval, FRAX scores were calculated both before and after multiplier adjustment, for patients included in our outpatient Fracture Liaison Service who had experienced a non-hip fragility fracture between June 2020 and November 2021. Patients age 50 years or older, with recent (within 3 months) forearm (radius and/or ulna) or humerus fractures were included. Exclusion criteria consisted of patients under the age of 50 years or those with a hip fracture. Age- and sex-based FRAX multipliers for recent forearm and humerus fractures described by McCloskey et al. (2021) were used to adjust the conventional FRAX score. Low, intermediate and high-risk of MOF was defined as less than 10%, 10-20%, and greater than 20%, respectively. Data are reported as mean and standard deviation of the mean for continuous variables and as proportions for categorical variables. A total of 91 patients with an average age of 64 years (range = 50-97) were included. The majority of patients were female (91.0%), with 73.6% sustaining forearm fractures and 26.4% sustaining humerus fractures. In the forearm group, the average MOF risk pre- and post-multiplier was 16.0 and 18.8, respectively. Sixteen percent of patients (n = 11) in the forearm group moved from intermediate to high 10-year fracture risk after multiplier adjustment. Average FRAX scores before and after adjustment in the humerus group were 15.7 and 22.7, respectively, with 25% (n = 6) of patients moving from an intermediate risk to a high-risk score. This study demonstrates the clinically significant impact of multipliers on conventional FRAX scores in patients with recent non-hip fractures. Twenty-five percent of patients with humerus fractures and 16% of patients with forearm fractures moved from intermediate to high-risk of MOF after application of the multiplier. Consequently, patients who were previously ineligible for pharmacologic management, now met criteria. Multiplier-adjusted FRAX scores after a recent fracture may more accurately identify patients with imminent fracture risk, facilitating earlier risk reduction interventions

Short cementless femoral stems are increasingly popular as they allow for less dissection for insertion. Use of such stems with the anterior approach (AA) may be associated with considerable per-operative fracture risk. This study's primary aim was to evaluate whether patient-specific femoral- and pelvic- morphology and surgical technique, influence per-operative fracture risk. In doing so, we aimed to describe important anatomical thresholds alerting surgeons. This is a single-center, multi-surgeon retrospective, case-control matched study. Of 1145 primary THAs with a short, cementless stem inserted via the AA, 39 periprosthetic fractures (3.4%) were identified. These were matched for factors known to increase fracture risk (age, gender, BMI, side, Dorr classification, stem offset and indication for surgery) with 78 THAs that did not sustain a fracture. Radiographic analysis was performed using validated software to measure femoral- (canal flare index [CFI], morphological cortical index [MCI], calcar-calcar ratio [CCR]) and pelvic- (Ilium-ischial ratio [IIR], ilium overhang, and ASIS to greater trochanter distance) morphologies and surgical technique (% canal fill). Multivariate and Receiver-Operator Curve (ROC) analysis was performed to identify predictors of fracture. Femoral factors that differed included CFI (3.7±0.6 vs 2.9±0.4, p3.17 and II ratio>3 (OR:29.2 95%CI: 9.5–89.9, p<0.001). Patient-specific anatomical parameters are important predictors of fracture-risk. When considering the use of short stems via the AA, careful radiographic analysis would help identify those at risk in order to consider alternative stem options

Bone turnover and the accumulation of microdamage are impacted by the presence of skeletal metastases which can contribute to increased fracture risk. Treatments for metastatic disease may further impact bone quality. The present study aims to establish a preliminary understanding of microdamage accumulation and load to failure in osteolytic vertebrae following stereotactic body radiotherapy (SBRT), zoledronic acid (ZA), or docetaxel (DTX) treatment. Twenty-two six-week old athymic female rats (Hsd:RH-Foxn1rnu, Envigo, USA) were inoculated with HeLa cervical cancer cells through intracardiac injection (day 0). Institutional approval was obtained for this work and the ARRIVE guidelines were followed. Animals were randomly assigned to four groups: untreated (n=6), spine stereotactic body radiotherapy (SBRT) administered on day 14 (n=6), zoledronic acid (ZA) administered on day 7 (n=5), and docetaxel (DTX) administered on day 14 (n=5). Animals were euthanized on day 21. T13-L3 vertebral segments were collected immediately after sacrifice and stored in −20°C wrapped in saline soaked gauze until testing. µCT scans (µCT100, Scanco, Switzerland) of the T13-L3 segment confirmed tumour burden in all T13 and L2 vertebrae prior to testing. T13 was stained with BaSO. 4. to label microdamage. High resolution µCT scans were obtained (90kVp, 44uA, 4W, 4.9µm voxel size) to visualize stain location and volume. Segmentations of bone and BaSO. 4. were created using intensity thresholding at 3000HU (~736mgHA/cm. 3. ) and 10000HU (~2420mgHA/cm. 3. ), respectively. Non-specific BaSO. 4. was removed from the outer edge of the cortical shell by shrinking the segmentation by 105mm in 3D. Stain volume fraction was calculated as the ratio of BaSO. 4. volume to the sum of BaSO. 4. and bone volume. The L1-L3 motion segments were loaded under axial compression to failure using a µCT compatible loading device (Scanco) and force-displacement data was recorded. µCT scans were acquired unloaded, at 1500µm displacement and post-failure. Stereological analysis was performed on the L2 vertebrae in the unloaded µCT scans. Differences in mean stain volume fraction, mean load to failure, and mean bone volume/total volume (BV/TV) were compared between treatment groups using one-way ANOVAs. Pearson's correlation between stain volume fraction and load to failure by treatment was calculated using an adjusted load to failure divided by BV/TV. Stained damage fraction was significantly different between treatment groups (p=0.0029). Tukey post-hoc analysis showed untreated samples to have higher stain volume fraction (16.25±2.54%) than all treatment groups (p<0.05). The ZA group had the highest mean load to failure (195.60±84.49N), followed by untreated (142.33±53.08N), DTX (126.60±48.75N), and SBRT (95.50±44.96N), but differences did not reach significance (p=0.075). BV/TV was significantly higher in the ZA group (49.28±3.56%) compared to all others. The SBRT group had significantly lower BV/TV than the untreated group (p=0.018). Load divided by BV/TV was not significantly different between groups (p=0.24), but relative load to failure results were consistent (ZA>Untreated>DTX>SBRT). No correlations were found between stain volume fraction and load to failure. Focal and systemic cancer treatments effect microdamage accumulation and load to failure in osteolytic vertebrae. Current testing of healthy controls will help to further separate the effects of the tumour and cancer treatments on bone quality

Bone turnover and the accumulation of microdamage are impacted by the presence of skeletal metastases which can contribute to increased fracture risk. Treatments for metastatic disease may further impact bone quality. The present study aims to establish a preliminary understanding of microdamage accumulation and load to failure in osteolytic vertebrae following stereotactic body radiotherapy (SBRT), zoledronic acid (ZA), or docetaxel (DTX) treatment. Twenty-two six-week old athymic female rats (Hsd:RH-Foxn1rnu, Envigo, USA) were inoculated with HeLa cervical cancer cells through intracardiac injection (day 0). Institutional approval was obtained for this work and the ARRIVE guidelines were followed. Animals were randomly assigned to four groups: untreated (n=6), spine stereotactic body radiotherapy (SBRT) administered on day 14 (n=6), zoledronic acid (ZA) administered on day 7 (n=5), and docetaxel (DTX) administered on day 14 (n=5). Animals were euthanized on day 21. T13-L3 vertebral segments were collected immediately after sacrifice and stored in −20°C wrapped in saline soaked gauze until testing. µCT scans (µCT100, Scanco, Switzerland) of the T13-L3 segment confirmed tumour burden in all T13 and L2 vertebrae prior to testing. T13 was stained with BaSO. 4. to label microdamage. High resolution µCT scans were obtained (90kVp, 44uA, 4W, 4.9µm voxel size) to visualize stain location and volume. Segmentations of bone and BaSO. 4. were created using intensity thresholding at 3000HU (~736mgHA/cm. 3. ) and 10000HU (~2420mgHA/cm. 3. ), respectively. Non-specific BaSO. 4. was removed from the outer edge of the cortical shell by shrinking the segmentation by 105mm in 3D. Stain volume fraction was calculated as the ratio of BaSO. 4. volume to the sum of BaSO. 4. and bone volume. The L1-L3 motion segments were loaded under axial compression to failure using a µCT compatible loading device (Scanco) and force-displacement data was recorded. µCT scans were acquired unloaded, at 1500µm displacement and post-failure. Stereological analysis was performed on the L2 vertebrae in the unloaded µCT scans. Differences in mean stain volume fraction, mean load to failure, and mean bone volume/total volume (BV/TV) were compared between treatment groups using one-way ANOVAs. Pearson's correlation between stain volume fraction and load to failure by treatment was calculated using an adjusted load to failure divided by BV/TV. Stained damage fraction was significantly different between treatment groups (p=0.0029). Tukey post-hoc analysis showed untreated samples to have higher stain volume fraction (16.25±2.54%) than all treatment groups (p<0.05). The ZA group had the highest mean load to failure (195.60±84.49N), followed by untreated (142.33±53.08N), DTX (126.60±48.75N), and SBRT (95.50±44.96N), but differences did not reach significance (p=0.075). BV/TV was significantly higher in the ZA group (49.28±3.56%) compared to all others. The SBRT group had significantly lower BV/TV than the untreated group (p=0.018). Load divided by BV/TV was not significantly different between groups (p=0.24), but relative load to failure results were consistent (ZA>Untreated>DTX>SBRT). No correlations were found between stain volume fraction and load to failure. Focal and systemic cancer treatments effect microdamage accumulation and load to failure in osteolytic vertebrae. Current testing of healthy controls will help to further separate the effects of the tumour and cancer treatments on bone quality

Aim. To conduct a systematic review and meta-analysis comparing the development of early and late fracture-related infections (FRI) following closed and open fractures in HIV-positive and HIV-negative patients. Method. A systematic literature search was conducted using MEDLINE through the OVID interface, ProQuest, Web of Science, The Cochrane Library and Scopus. Only studies involving HIV-positive who underwent operative fixation (internal or external) of open or closed fractures, with a HIV-negative control group, were considered eligible. Following eligibility assessment, studies were included with the main outcome of interest being the development of either early or late fracture-related infection at the site of surgery in patients with open and closed fractures. Results. Eleven studies were included (n = 2634). The studies’ follow-up periods were between one and 39 months with an average of 11 months. Three studies were conducted before the introduction of ARV (anti-retroviral) therapy (1994) and two did not involve any patients on ARV's. Across the entire group, for both open and closed fractures, the risk of a fracture-related infection was greater in HIV-positive patients (Odds ratio (OR) = 1.61; 95% CI = 0.93–2.79, p = 0.04). When looking at closed fractures treated operatively, an OR = 4.59 was found in HIV-positive patients in terms of the risk of fracture-related infection (95% CI = 0.30–68.99, p < 0.001). Open fractures showed similar results with an OR of 3.48 in HIV-positive patients (95% CI = 0.55 – 21.99, p < 0.001). Studies performed prior to the widespread introduction of anti-retroviral therapy and/or did not have any patients on antiretroviral therapy showed a greater infection risk in patients living with HIV infection with OR 3.53 (95% CI = 1.85 – 6.74, p = 0.36). However, studies performed in the era after the introduction of antiretroviral therapy showed no increase of infection risk for HIV-positive patients with an OR = 0.91 (95% CI = 0.58 – 1.43, p = 0.76). Conclusions. The assumption that HIV infection increases the risk for fracture-related infection remains unsubstantiated. The introduction of anti-retroviral therapy may have confounded the issue and we noted an apparent decrease in the risk in later studies. More data is required from well-designed larger studies to inform future analysis

In conventional DXA (Dual-energy X-ray Absorptiometry) analysis, pixel bone mineral density (BMD) is often averaged at the femoral neck. Neck BMD constitutes the basis for osteoporosis diagnosis and fracture risk assessment. This data averaging, however, limits our understanding of localised spatial BMD patterns that could potentially enhance fracture prediction. DXA region free analysis (RFA) is a validated toolkit for pixel-level BMD analysis. We have previously deployed this toolkit to develop a spatio-temporal atlas of BMD ageing in the femur. This study aims first to introduce bone age to reflect the overall bone structural evolution with ageing, and second to quantify fracture-specific patterns in the femur. The study dataset comprised 4933 femoral DXA scans from White British women aged 75 years or older. The total number of fractures was 684, of which 178 were reported at the hip within a follow-up period of five years. BMD maps were computed using the RFA toolkit. For each BMD map, bone age was defined as the age for which the L2-norm between the map and the median atlas at that age is minimised. Next, bone maps were normalised for the estimated bone age. A t-test followed by false discovery rate (FDR) analysis was applied to compare between fracture and non-fracture groups. Excluding the ageing effect revealed subtle localised patterns of loss in BMD oriented in the same direction as principal tensile curves. A new score called f-score was defined by averaging the normalised pixel BMD values over the region with FDR q-value less than 1e–6. The area under the curve (AUC) was 0.731 (95% confidence interval (CI)=0.689–0.761) and 0.736 (95% CI=0.694–0.769) for neck BMD and f-score. Combining bone age and f-score improved the AUC significantly by 3% (AUC=0.761, 95% CI=0.756–0.768) over the neck BMD alone (AUC=0.731, 95% CI=0.726–0.737). This technique shows promise in characterizing spatially-complex BMD changes, for which the conventional region-based technique is insensitive. DXA RFA shows promise to further improve fracture prediction using spatial BMD distribution

Orthopaedic surgeons frequently assess fragility fractures (FF), however osteoporosis (OP) is often managed by primary care physicians (PCP). Up to 48% of FF patients have had a previous fracture (Kanis et al., 2004). Discontinuity between fracture care and OP management is a missed opportunity to reduce repeat fractures. This studied aimed to evaluate current OP management in FF patients presenting to cast clinic. A single centre, prospective observational study where seven traumatologists screened for FF in cast clinic. FF was defined as a hip, distal radius (DR), proximal humerus (PH), or ankle fracture due to a ground level fall. Patients completed a self-administered questionnaire for demographics, fracture type and treatment, medical and fracture history, and previous OP care. The primary outcome was number of FF patients who received OP investigation and/or treatment. Secondary outcomes included Fracture Risk Assessment Tool (FRAX), repeat fracture rate, and anti-resorptive related fractures. Descriptive statistics were used for analysis. Between November 17, 2014 and October 13, 2015, a total of 1,677 patients attended cast clinic for an initial assessment. FF were identified in 120 patients (7.2%). The FF cohort had a mean age of 65.3 (± 14.3) years, mean BMI of 26.1 (± 5.3), and was comprised of 83.3% females. Fracture distribution was 69 (57.5%) DR, 23 (19%) ankle, 20 (16.5%) PH, and seven (5.8%) hip fractures, with 24 of the FF (19.8%) treated operatively. Thirteen (10.8%) were current smokers and 40 (33.3%) formerly smoked. A history of steroid use was present in 13 patients (10.8%). Ninety (n = 117; 76.9%) of patients ambulated independently. Twenty-two patients (18.3%) reported prior diagnosis of OP, most often by a PCP (n = 19; 73.7%) over 5 years previously. Calcium (n = 59; 49.2%) and Vitamin D (n = 70; 58.3%) were common and 26 patients (21.5%) had a prior anti-resorptive therapy, with Alendronate (n = 9) being most common. One patient had an anti-resorptive-related fracture. Raloxifene was used in ten patients. Forty-seven patients (39.2%) had a prior fracture at a mean age of 61.3 (± 11.9) years, with DR and PH fractures being most common. Eleven patients had two or more prior fractures. A family history of OP was found in 34 patients (28.1%). Mean FRAX score was 20.8% (± 10.8%) 10-year major fracture risk and 5.9% (± 6.6%) 10-year hip fracture risk (n = 30 bone densiometry within one-year). Of the 26 patients with a Moderate (10–20%) or High (> 20%) 10-year major fracture risk, only eight (30.8%) reported a diagnosis of OP and only three (11.5%) had seen an OP specialist. Cast clinics provide an opportunity for OP screening, initiation of treatment, and patient education. This cohort demonstrated a high rate of repeat fractures and poor patient reporting of prior OP diagnosis. This study likely underestimated FF and calls for resource allocation for quantifying true burden of disease and outpatient fracture liaison service

Bones are thought to become fragile with advancing age due to a loss of mass and structure. However, there are important aspects of bone fragility and fracture that cannot be explained simply by a loss of bone: 30% of all patients told they have healthy bone based on bone mineral density (BMD) measurements go on to fracture. It has been suggested that increased fracture risk might also be due to ageing at the nanoscale, which might deteriorate the overall mechanical properties of a bone. However, it is not clear how mechanics at the level of the collagen-mineral matrix relate to mechanical properties of the whole bone, or whether nano-mechanics contribute to fracture risk. In order to answer these questions our group is developing state of the art methods for analysing the structure and function of the collagen mineral matrix under loading. To image the collagen mineral matrix we obtained beam time on a synchrotron particle accelerator at the Diamond Light Source (Didcot, UK). Electrons are accelerated to near light speed by powerful electromagnets, then slowed to create high energy monochromatic X-Ray beams. Through a combination of X-Ray computed tomography and X-Ray diffraction we have been able to image the collagen/mineral matrix. Furthermore, using in situ loading experiments it has been possible to visualise collagen fibrillar sliding and mineral crystal structure. Our group is analysing how age related changes in nano-structure affect bone mechanical behaviour. As well as comparing fragility fracture patients with ‘healthy’ age matched controls to investigate whether ageing at the nano-scale could increase fracture risk. We are also assessing the effect of common treatments for bone fragility (e.g. bisphosphonate) on nano-mechanics. Unfortunately the expense and high radiation dose associated with synchrotron imaging prevents the technology from being adapted for patients. Therefore the next step will be to identify and test tools that can be used to indirectly assess bone chemistry and mechanical properties at point of care (e.g. laser spectroscopy and indentation). The data could be used to improve the diagnosis, monitoring and treatment of bone fragility

Fragility fractures associated with osteoporosis (OP) reduce quality of life, increase risk for subsequent fractures, and are a major economic burden. In 2010, Osteoporosis Canada produced clinical practice guidelines on the management of OP patients at risk for fractures (Papaioannou et al. CMAJ 2010). We describe the real-world incidence of primary and subsequent fragility fractures in elderly Canadians in Ontario, Canada in a timespan (2011–2017) following guideline introduction. This retrospective observational study used de-identified health services administrative data generated from the publicly funded healthcare system in Ontario, Canada from the Institute for Clinical Evaluative Sciences. The study population included individuals ≥66 years of age who were hospitalized with a primary (i.e. index) fragility fracture (identified using ICD-10 codes from hospital admissions, emergency and ambulatory care) occurring between January 1, 2011 and March 31, 2015. All relevant anatomical sites for fragility fractures were examined, including (but not limited to): hip, vertebral, humerus, wrist, radius and ulna, pelvis, and femur. OP treatment in the year prior to fracture and subsequent fracture information were collected until March 31, 2017. Patients with previous fragility fractures over five years prior to the index fracture, and those fractures associated with trauma codes, were excluded. 115,776 patients with an index fracture were included in the analysis. Mean (standard deviation) age at index fracture was 80.4 (8.3) years. In the year prior to index fracture, 32,772 (28.3%) patients received OP treatment. The incidence of index fractures per 1,000 persons (95% confidence interval) from 2011–2015 ranged from 15.16 (14.98–15.35) to 16.32 (16.14–16.51). Of all examined index fracture types, hip fractures occurred in the greatest proportion (27.3%) of patients (Table). The proportion of patients incurring a second fracture of any type ranged from 13.4% (tibia, fibula, knee, or foot index fracture) to 23% (vertebral index fracture). Hip fractures were the most common subsequent fracture type and the proportion of subsequent hip fractures was highest in patients with an index hip fracture (Table). The median (interquartile range [IQR]) time to second fracture ranged from 436 (69–939) days (radius and ulna index fracture) to 640 (297–1,023) days (tibia, fibula, knee, or foot index fracture). The median (IQR) time from second to third fracture ranged from 237 (75–535) days (pelvis index fracture) to 384 (113–608) days (femur index fracture). This real-world study found that elderly patients in Ontario, Canada incurring a primary fragility fracture from 2011–2015 were at risk for future fractures occurring over shorter periods of time with each subsequent fracture. These observations are consistent with previous reports of imminent fracture risk and the fragility fracture cascade in OP patients (Balasubramanian et al. ASBMR 2016, Toth et al. WCO-IOF-ESCEO 2018). Overall, these data suggest that in elderly patients with an index fragility fracture at any site (with the exception of the radius or ulna), the most likely subsequent fracture will occur at the hip in less than 2 years

INTRODUCTION. The restoration of the anatomical hip rotation center (HRC) has a major influence on the longevity of hip prostheses. Deviations from the HRC of the anatomical joint after total hip arthroplasty (THA) can lead to increased hip joint forces, early wear or loosening of the implant. The contact conditions of acetabular press-fit cups after implantation, including the degree of press-fit, the existence of a polar gap and cup orientation, may affect the HRC restoration, and therefore implant stability. The aim of this study was to determine the influence of acetabular press-fit, polar gap and cup orientation on HRC restoration during THA. METHODS. THAs were performed by an experienced orthopaedic surgeon in full cadaveric models simulating real patient surgery (n=7). Acetabular cups with a Porocoat™ (n=3) and Gription™ surface coating (n=4) were implanted (DePuy Synthes, Leeds, UK). Computed tomography (CT) scans prior to surgery, as well as after reaming and implantation of press-fit cups were used to calculate the HRC displacement. After aligning the pelves in the anterior pelvic plane, 3D reconstruction of the HRC at each stage was performed by fitting spheres to the femoral head, the reamed cavity and the inserted cup. 3D surface models of the cups were generated using a laser scanner and were registered to the CT images. The effective press-fit was calculated using the diameters of spheres, fitted to the cavity prior to cup insertion and to the outer cup coating. The polar gap was defined as the difference between the outer cup surface and the subchondral bone at the cup pole. Anteversion and abduction angles were calculated as difference between the cup planes and the sagittal and transverse plane, respectively. RESULTS. A medial (6.4±1.6mm), superior (5.1±1.5mm) and posterior (3.0±1.4mm) displacement of the HRC after reaming was measured. A significant inferior shift of the HRC could be measured after cup implantation (p=0.043). No significant influence of the coating design on the HRC shift could be observed. The shift of the HRC back towards the anatomical HRC was highly correlated to the degree of polar gap (R. 2. =0.928, p<0.001) and a trend towards an association with effective press-fit was observed (R. 2. =0.536, p=0.061). The cup angles had no influence on the shift of the HRC, but a high variability in cup anteversion (20.7° to 61.8°) was observed. DISCUSSION. The study suggests that increasing the press-fit and polar gap improves the restoration of the anatomical HRC. Since increasing the degree of press-fit could also lead to higher stresses and an increased fracture risk, future work will study how the acetabular contact conditions influence both primary implant stability and fracture risk, in order to establish an optimal HRC reconstruction to maximize implant longevity

While total hip arthroplasty (THA) has been shown successful at relieving pain and improving function in patients with coxarthrosis, wear and instability remain leading causes for revision surgery. Highly crosslinked polyethylene (HXPE) has significantly reduced wear and osteolysis but volumetric wear associated with the use of larger diameter ball heads may be an issue in the long-term. Finally, concerns with femoral taper corrosion have increased the utilization of ceramic ball heads in recent years. Ceramic on ceramic articulations are optimised for both minimizing implant wear and instability. It is biocompatible, wettable, and possesses the lowest in vitro and in vivo wear rates among all bearing couples. In fact, wear rates are lowest when the ceramic ball head size is maximised. Additionally, modern ceramic on ceramic THA designs have had an excellent clinical track record with low rates of loosening, failure, and no reports of osteolysis in even highly active, young patients. Concerns with ceramics center around issues related to fracture risk, squeaking, and cost. While the phenomenon of squeaking remains poorly understood, the reliability of ceramic implants have steadily improved with better materials, design, and manufacturing. The fracture risk for modern pure alumina implants and the newer alumina matrix composite ceramics are 1 in 5000 and 1 in 100,000, respectively. The advantages of ceramic on ceramic THAs will not be realised on every patient and therefore, should be selectively used. However, with expected increases in life expectancy and more young, active patients undergoing THA, ceramic on ceramic THA should be strongly considered in patients under age 60 years

Introduction. The Rotational alignment is an important factor for survival total knee Arthroplasty. Rotational malalignment causes knee pain, global instability, and wear of the polyethylene inlay. Also, the anterior cortex line was reported that more reliable and more easily identifiable landmark for correct tibial component alignment. The aims of the current study is to identify effect of inserting the tibial baseplate of using anterior cortex line landmark of TKA on stress/strain distributions within cortical bone and bone cement. Through the current study, final aim is to suggest an alternative position of tibia baseplate for reduction of TKA failures with surgical convenience. Materials and Method. A three-dimensional tibia FE model with TKA was generated based on a traditional TKA surgical guideline. Here, a commercialized TKA (LOSPA, Corentc, Korea) was considered corresponded to a patient specific tibia morphology. Tibia baseplate was positioned at anterior cortex line. Alternative two positions were also considered based on tibia tuberosity 1/3 line and tibia tuberosity end line known as a gold standard (Fig. 1-A). Loading and boundary conditions for the FE analysis were determined based on five activities of daily life of persons with TKA (Fig. 1-B). FE model was additionally validated comparing with an actual mechanical test. Results and Discussions. The, through comparing with strain distribution on the cortical bone measured from the actual mechanical test considering 0°, 30° 60°, 90°, 120° and 140° flexion with femoral rollback phenomenon (Fig. 2). Stress/strain on the cortical bone (medial region) of the proximal tibia for the baseplate positioned at anterior cortex line were a little better distributed than those at tibia tuberosity 1/3 line and tibia tuberosity end line although the stress/stain values were similar to each other (Fig. 3-A). Potential fracture risk of the bone cement for the baseplate positioned at anterior cortex line was lower than that at tibia tuberosity 1/3 line and tibia tuberosity end line, considering safety factor (N=3). Particularly, Potential fracture risk of the bone cement for the baseplate positioned at tibia tuberosity 1/3 line known as a gold standard was highest (over 20MPa for stair down activity) (Fig. 3-B). Conclusion. Our results suggested that anterior cortex line landmark was feasible to apply positioning method on the tibial baseplate in terms of mechanical characteristics which were compared to tibia tuberosity 1/3 line and tibia tuberosity end line known as a gold standard. This study may be valuable by suggesting for the first time an alternative baseplate position for reduction of TKA failures with surgical convenience

There has been an evolution in revision hip arthroplasty towards cementless reconstruction. Whilst cemented arthroplasty works well in the primary setting, the difficulty with achieving cement fixation in femoral revisions has led to a move towards removal of cement, where it was present, and the use of ingrowth components. These have included proximally loading or, more commonly, distally fixed stems. We have been through various iterations of these, notably with extensively porous coated cobalt chrome stems and recently with taper-fluted titanium stems. As a result of this, cemented stems have become much less popular in the revision setting. Allied to concerns about fixation and longevity of cemented fixation revision, there were also worries in relation to bone cement implantation syndrome when large cement loads were pressurised into the femoral canal at the time of stem cementation. This was particularly the case with longer stems. Technical measures are available to reduce that risk but the fear is nevertheless there. In spite of this direction of travel and these concerns, there is, however, still a role for cemented stems in revision hip arthroplasty. This role is indeed expanding. First and foremost, the use of cement allows for local antibiotic delivery using a variety of drugs both instilled in the cement at the time of manufacture or added by the surgeon when the cement is mixed. This has advantages when dealing with periprosthetic infection. Thus, cement can be used both as interval spacers but also for definitive fixation when dealing with periprosthetic hip infection. The reconstitution of bone stock is always attractive, particularly in younger patients or those with stove pipe canals. This is achieved well using impaction grafting with cement and is another extremely good use of cement. In the very elderly or those in whom proximal femoral resection is needed at the time of revision surgery, distal fixation with cement provides a good solution for immediate weight bearing and does not have the high a risk of fracture seen with large cementless stems. Cement is also useful in cases of proximal femoral deformity or where cement has been used in a primary arthroplasty previously. We have learnt that if the cement is well-fixed then the bond of cement-to-cement is excellent and therefore retention of the cement mantle and recementation into that previous mantle is a great advantage. This avoids the risks of cement removal and allows for much easier fixation. Stems have been designed specifically to allow this cement-in-cement technique. It can be used most readily with polished tapered stems - tap out a stem, gain access at the time of revision surgery and reinsert it. It is, however, now increasingly used when any cemented stems are removed provided that the cement mantle is well fixed. The existing mantle is either wide enough to accommodate the cement-in-cement revision or can be expanded using manual instruments or ultrasonic tools. The cement interface is then dried and a new stem cemented in place. Whilst the direction of travel in revision hip arthroplasty has been towards cementless fixation, particularly with tapered distally fixed designs, the reality is that there is still a role for cement for its properties of immediate fixation, reduced fracture risk, local antibiotic delivery, impaction grafting and cement-in-cement revision

Incidence of intraoperative fracture during cementless Total Hip Arthroplasty (THA) is increasing. This is attributed to factors such as an increase in revision procedures and the favour of cementless fixation. Intraoperative fractures often occur during the seating of cementless components. A surgical mallet and introducer are used to generate the large impaction forces necessary to seat the component, sometimes leading to excessive hoop strain in the bone. The mechanisms of bone strain during impaction are complex and occur over very short timeframes. For this reason experimental and simulation models often focus on strain shortly after the implant is introduced, or seat it quasi-statically. This may not produce a realistic representation of the magnitude of strain in the bone and dangerously under-represent fracture risk. This in-vitro study seeks to determine whether strain induced during impaction is similar both during the strike (dynamic strain) and shortly after the strike has occurred (post-strike strain). It is also asked whether post-strike strain is a reliable predictor of dynamic strain. A custom drop tower was used to seat acetabular components in 45 Sawbones models (SKU: 1522–02, Malmo, Sweden), CNC milled to represent the acetabular cavity. Ten strikes were used to seat each cup. 3 strike velocities (1.5 m/s, 2.75 m/s, 4 m/s) and 3 impact masses (600 g, 1.2 kg, 1.8 kg) were chosen to represent 9 different surgical scenarios. Two strain gages per Sawbone were mounted on the surface of the block, 2 mm from the rim of the cavity. Strain data was acquired at 50 khz. Each strain trace was then analysed to determine the peak dynamic strain during mallet strike and the static strain post-strike. A typical strain pattern was observed during seating. An initial pre-strike strain is followed by a larger dynamic peak as the implant is progressed into the bone cavity. Strain subsequently settles at a lower (tensile) value than peak dynamic post-strike, but higher than pre-strike strain. Over the 450 strikes conducted dynamic strain was on average 3.39 times larger than post-strike strain. A statistically significant linear relationship was observed between the magnitude of post-strike and dynamic strain (adjusted R. 2. =0.391, p<0.005). This indicates that, for a known scenario, post-strike strain can be used as an indicator for dynamic peak strain. However when only the maximum dynamic and post-strike strains were taken from across the 10 strikes used to seat the implant, the relationship between the two strains was not significant (R. 2. =0.300, p=0.73). This may be due to the fact that the two maximums did not often occur on the same strike. On average, max dynamic strain occurred 1.7 strikes after max post-strike strain. We conclude that peak dynamic strain is much larger than the strain immediately post-strike in a synthetic bone model. It is shown that post-strike strain is not a good predictor of dynamic strain when the max strain during any strike to seat the component is considered, or variables (such as mallet mass or velocity) are changed. It is important to consider dynamic strain in bone as well as post-strike strain in experimental or simulated bone models to ensure the most reliable prediction of fracture

Aims. Dead space management is an important element in the surgical management of chronic osteomyelitis and can be addressed with the use of a biodegradable local antibiotic carrier. We present the clinical and radiographic outcomes in two different biodegradable antibiotic carriers used in the management of chronic osteomyelitis. Method. A single centre series reviewed between 2006–2017. The initial cohort (2006–2010) of 180 cases (Group A) had a calcium sulphate carrier containing tobramycin (Osteoset. ®. T, Wright Medical). The second cohort (2013–1017) of 162 cases (Group B) had a biphasic calcium sulphate, nano-crystalline hydroxyapatite carrier containing gentamicin (Cerament. TM. G, Bonesupport AB). All cases were Cierny-Mader Grade III and IV and had a minimum of one-year clinical follow-up. Clinical outcomes reviewed included infection recurrence rate, wound leak, and subsequent fracture involving the treated segment. All cases with a minimum one-year radiographic follow-up were reviewed and bone void filling was assessed as percentage filling on the final follow-up radiograph to the nearest five percent increment. Results. Mean follow-up in Group A was 4.2 years (range 1.3–10.5 years) and in Group B it was 1.8 years (1–4.7 years). Group A had a significantly higher rate of infection recurrence (19/180 (10.6%) Vs. 7/163 (4.4%) p=0.030), wound leak (33/180 (18.3.%) Vs. 16/162 (9.9%) p=0.026) and subsequent fracture rate (11/180 (6.1%) Vs. 3/162 (1.9%) p=0.047) compared to Group B. Of the cases with a minimum of one-year radiographic follow-up Group A had 96 cases (mean follow-up 3.3 years, range 1.0–10.5 years) and Group B had 137 cases (mean follow-up 1.6 years, range 1.0–4.7 years). The mean bone void healing in Group B was significantly better than Group A (74.0% Vs. 41.7%, p <0.00001). Conclusions. Cerament. TM. G has significantly better bone healing compared to a calcium sulphate carrier and was associated with a lower rate of recurrent infection, wound leak and subsequent fracture risk

There are pros and cons of all bearing surface options for our young patients. I pick the bearing surface for my young patients trying to maximise durability and minimise risks. For the ultra-young, ≤30 years of age patient, I use ceramic-on-ceramic. The pros of this are the best wear couple available and a favorable track record (with well designed implants). The risks can be minimised: fracture risk now decreased, runaway wear minimised with good surgical technique, impingement problems minimised with good technique and well designed implants, as well as squeaking is minimised with good design (majority of reported squeakers are of one designed socket). I don't use metal-on-metal because I am not willing to subject young patients to potentially 50+ years of high metal ion exposure. I also don't use HCLPE. This would be okay from a biologic standpoint but I still have concerns about long-term wear durability. So the marked superior wear characteristics of ceramic-ceramic win in my view. For my middle age patients, 30–60, I use HCLPE I don't use ceramic-ceramic because at some point between 30 and 60 years of age the improved wear properties are outweighed by their potential risks (fracture, impingement, squeak). HCLPE at short F/U (<15 years) appears to be durable, reliable with good wear properties so it is a reasonable choice. Using a ceramic head versus CoCr provides minimal improvement in wear properties in the lab but no marked advantage in vivo. Concerns persist about cobalt-chrome corrosion so I use ceramic heads in the majority of patients. For patients under age 60 the wear characteristics of HCLPE appear very favorable and one doesn't assume other risks seen in with metal-on-metal and ceramic-ceramic. Little justification for a hard-on-hard bearing in this patient subgroup. I use ceramic heads in majority to avoid corrosion issues