Lumbar and Thoracic Vertebrae Segmentation in CT Scans Using a 3D Multi-Object Localization and Segmentation CNN.

Radiation treatment of cancers like prostate or cervix cancer requires considering nearby bone structures like vertebrae. In this work, we present and validate a novel automated method for the 3D segmentation of individual lumbar and thoracic vertebra in computed tomography (CT) scans. It is based on a single, low-complexity convolutional neural network (CNN) architecture which works well even if little application-specific training data are available. It is based on volume patch-based processing, enabling the handling of arbitrary scan sizes. For each patch, it performs segmentation and an estimation of up to three vertebrae center locations in one step, which enables utilizing an advanced post-processing scheme to achieve high segmentation accuracy, as required for clinical use. Overall, 1763 vertebrae were used for the performance assessment. On 26 CT scans acquired for standard radiation treatment planning, a Dice coefficient of 0.921 ± 0.047 (mean ± standard deviation) and a signed distance error of 0.271 ± 0.748 mm was achieved. On the large-sized publicly available VerSe2020 data set with 129 CT scans depicting lumbar and thoracic vertebrae, the overall Dice coefficient was 0.940 ± 0.065 and the signed distance error was 0.109 ± 0.301 mm. A comparison to other methods that have been validated on VerSe data showed that our approach achieved a better overall segmentation performance.

Supervised machine learning for the prediction of post-operative clinical outcomes of hip and knee replacements: a review.

Prediction models are being increasingly used in the medical field to identify risk factors and possible outcomes. Some of these are presently being used to develop guidelines for improving clinical practice. The application of machine learning (ML), comprising a powerful set of computational tools for analysing data, has been clearly expanding in the role of predictive modelling. This paper reviews the latest developments of supervised ML techniques that have been used to analyse data related to post-operative total hip and knee replacements. The aim was to review the most recent findings of relevant published studies by outlining the methodologies employed (most-widely used supervised ML techniques), data sources, domains, limitations of predictive analytics and the quality of predictions.

A re-activation model for 169Yb intensity modulated brachytherapy sources accounting for spatiotemporal isotopic composition.

BACKGROUND: Intensity modulated brachytherapy based on partially shielded intracavitary and interstitial applicators is possible with a cost-effective 169Yb production method. 169Yb is a traditionally expensive isotope suitable for this purpose, with an average γ-ray energy of 93 keV. Re-activating a single 169Yb source multiple times in a nuclear reactor between clinical uses was shown to theoretically reduce cost by approximately 75% relative to conventional single-activation sources. With re-activation, substantial spatiotemporal variation in isotopic source composition is expected between activations via 168Yb burnup and 169Yb decay, resulting in time dependent neutron transmission, precursor usage, and reactor time needed per re-activation. PURPOSE: To introduce a generalized model of radioactive source production that accounts for spatiotemporal variation in isotopic source composition to improve the efficiency estimate of the 169Yb production process, with and without re-activation. METHODS AND MATERIALS: A time-dependent thermal neutron transport, isotope transmutation, and decay model was developed. Thermal neutron flux within partitioned sub-volumes of a cylindrical active source was calculated by raytracing through the spatiotemporal dependent isotopic composition throughout the source, accounting for thermal neutron attenuation along each ray. The model was benchmarked, generalized, and applied to a variety of active source dimensions with radii ranging from 0.4 to 1.0 mm, lengths from 2.5 to 10.5 mm, and volumes from 0.31 to 7.85 mm3, at thermal neutron fluxes from 1 × 1014 to 1 × 1015 n cm-2 s-1. The 168Yb-Yb2O3 density was 8.5 g cm-3 with 82% 168Yb-enrichment. As an example, a reference re-activatable 169Yb active source (RRS) constructed of 82%-enriched 168Yb-Yb2O3 precursor was modeled, with 0.6 mm diameter, 10.5 mm length, 3 mm3 volume, 8.5 g cm-3 density, and a thermal neutron activation flux of 4 × 1014 neutrons cm-2 s-1. RESULTS: The average clinical 169Yb activity for a 0.99 versus 0.31 mm3 source dropped from 20.1 to 7.5 Ci for a 4 × 1014 n cm-2 s-1 activation flux and from 20.9 to 8.7 Ci for a 1 × 1015 n cm-2 s-1 activation flux. For thermal neutron fluxes ≥2 × 1014 n cm-2 s-1, total precursor and reactor time per clinic-year were maximized at a source volume of 0.99 mm3 and reached a near minimum at 3 mm3. When the spatiotemporal isotopic composition effect was accounted for, average thermal neutron transmission increased over RRS lifetime from 23.6% to 55.9%. A 28% reduction (42.5 days to 30.6 days) in the reactor time needed per clinic-year for the RRS is predicted relative to a model that does not account for spatiotemporal isotopic composition effects. CONCLUSIONS: Accounting for spatiotemporal isotopic composition effects within the RRS results in a 28% reduction in the reactor time per clinic-year relative to the case in which such changes are not accounted for. Smaller volume sources had a disadvantage in that average clinical 169Yb activity decreased substantially below 20 Ci for source volumes under 1 mm3. Increasing source volume above 3 mm3 adds little value in precursor and reactor time savings and has a geometric disadvantage.

A comparison of cemented femoral fixation via anterior versus posterior approach total hip arthroplasty: an analysis of 60,739 total hip arthroplasties.

BACKGROUND: Anterior approach total hip arthroplasty (THA) decreases the rate of dislocation but increases femoral-sided complications in the way of periprosthetic fractures and component loosening. A cemented prosthesis may reduce femoral-sided complications and improve the risk:benefit profile of anterior approach THA. METHODS: Data from the Australian National Joint Replacement Registry were analysed for patients undergoing primary THA via the anterior or posterior approach using a cemented polished femoral stem from January 2015 to December 2021. The primary outcome measure was the cumulative percent revision (CPR) for all causes and CPR for femoral component loosening and fracture. The CPR for the primary outcome measures were compared between the anterior and posterior approach and adjusted for age, sex, ASA score, BMI and femoral head size. RESULTS: The study included 60,739 THAs with cemented stems (10,742 anterior, 49,997 posterior). The rate of revision of the anterior versus the posterior approach did not significantly differ (HR 0.87 (95% CI, 0.74-1.03), p = 0.100). Anterior approach THA had a significantly higher rate of revision for femoral component loosening (HR 5.06 [95% CI, 3.08-8.30], p < 0.001); and a decreased rate of revision for infection (HR 0.59 [95% CI, 0.43-0.81], p = 0.001) and dislocation/instability (HR 0-3 months 0.48 [95% CI, 0.27-0.83], p = 0.008; HR >3 months 0.30 [95% CI, 0.15-0.61], p < 0.001). There was no difference in the rate of revision surgery for fracture between the 2 approaches (HR 1.01 [95% CI, 0.71-1.43]), p = 0.975). CONCLUSIONS: There is no significant difference in overall revision rates with cemented femoral fixation performed with an anterior or posterior approach. Cemented fixation performed with the anterior approach partly mitigates femoral complications with no difference in the revision rate for fracture but an increased rate of femoral component loosening.

Pre-clinical evaluation of biomarkers for the early detection of nephrotoxicity following alpha-particle radioligand therapy.

PURPOSE: Cancer treatment with alpha-emitter-based radioligand therapies (α-RLTs) demonstrates promising tumor responses. Radiolabeled peptides are filtered through glomeruli, followed by potential reabsorption of a fraction by proximal tubules, which may cause acute kidney injury (AKI) and chronic kidney disease (CKD). Because tubular cells are considered the primary site of radiopeptides' renal reabsorption and potential injury, the current use of kidney biomarkers of glomerular functional loss limits the evaluation of possible nephrotoxicity and its early detection. This study aimed to investigate whether urinary secretion of tubular injury biomarkers could be used as an additional non-invasive sensitive diagnostic tool to identify unrecognizable tubular damage and risk of long-term α-RLT nephrotoxicity. METHODS: A bifunctional cyclic peptide, melanocortin 1 ligand (MC1L), labeled with [203Pb]Pb-MC1L, was used for [212Pb]Pb-MC1L biodistribution and absorbed dose measurements in CD-1 Elite mice. Mice were treated with [212Pb]Pb-MC1L in a dose-escalation study up to levels of radioactivity intended to induce kidney injury. The approach enabled prospective kidney functional and injury biomarker evaluation and late kidney histological analysis to validate these biomarkers. RESULTS: Biodistribution analysis identified [212Pb]Pb-MC1L reabsorption in kidneys with a dose deposition of 2.8, 8.9, and 20 Gy for 0.9, 3.0, and 6.7 MBq injected [212Pb]Pb-MC1L doses, respectively. As expected, mice receiving 6.7 MBq had significant weight loss and CKD evidence based on serum creatinine, cystatin C, and kidney histological alterations 28 weeks after treatment. A dose-dependent urinary neutrophil gelatinase-associated lipocalin (NGAL, tubular injury biomarker) urinary excretion the day after [212Pb]Pb-MC1L treatment highly correlated with the severity of late tubulointerstitial injury and histological findings. CONCLUSION: Urine NGAL secretion could be a potential early diagnostic tool to identify unrecognized tubular damage and predict long-term α-RLT-related nephrotoxicity.

AAPM Medical Physics Practice Guideline 14.a: Yttrium-90 microsphere radioembolization.

Radioembolization using Yttrium-90 (90 Y) microspheres is widely used to treat primary and metastatic liver tumors. The present work provides minimum practice guidelines for establishing and supporting such a program. Medical physicists play a key role in patient and staff safety during these procedures. Products currently available are identified and their properties and suppliers summarized. Appropriateness for use is the domain of the treating physician. Patient work up starts with pre-treatment imaging. First, a mapping study using Technetium-99m (Tc-99m ) is carried out to quantify the lung shunt fraction (LSF) and to characterize the vascular supply of the liver. An MRI, CT, or a PET-CT scan is used to obtain information on the tumor burden. The tumor volume, LSF, tumor histology, and other pertinent patient characteristics are used to decide the type and quantity of 90 Y to be ordered. On the day of treatment, the appropriate dose is assayed using a dose calibrator with a calibration traceable to a national standard. In the treatment suite, the care team led by an interventional radiologist delivers the dose using real-time image guidance. The treatment suite is posted as a radioactive area during the procedure and staff wear radiation dosimeters. The treatment room, patient, and staff are surveyed post-procedure. The dose delivered to the patient is determined from the ratio of pre-treatment and residual waste exposure rate measurements. Establishing such a treatment modality is a major undertaking requiring an institutional radioactive materials license amendment complying with appropriate federal and state radiation regulations and appropriate staff training commensurate with their respective role and function in the planning and delivery of the procedure. Training, documentation, and areas for potential failure modes are identified and guidance is provided to ameliorate them.

Chemokine Receptor CXCR4 Radioligand Targeted Therapy Using 177Lutetium-pentixather for Pulmonary Neuroendocrine Cancers.

Intermediate to high-grade lung neuroendocrine tumors (NETs; i.e., atypical carcinoid tumors) and neuroendocrine carcinomas (NECs) are currently difficult to cure. These tumors were found to express the CXCR4 G-protein coupled receptor that can be targeted with radioligands. PCR and flow cytometric analysis of lung NET and NEC cell lines using an anti-CXCR4 antibody demonstrated that all cell lines tested expressed CXCR4. PET/CT imaging with 68Galium-pentixafor in mouse xenografts of NETs and NECs verified tumor targeting that was blocked by a CXCR4 agonist. Clonogenic survival analysis demonstrated a more than additive enhancement of killing when 1 µM auranofin (a thioredoxin reductase inhibitor) was used as a radiosensitizer in combination with 177Lu-pentixather (10 µCi). DMS273 small cell lung cancer xenografts in female nude mice treated with 25 µCi/g 177Lu-pentixather induced inhibition of tumor growth and resulted in an increase in overall survival without causing unacceptable normal tissue toxicities. Immunohistochemical staining of 95 retrospective human samples (containing 90 small cell lung carcinomas) demonstrated 84% CXCR4 positivity. In a multivariable analysis of this cohort that included age, gender, stage, primary site, SSTR2 status, and CXCR4 status, Cox regression models determined that only distant metastasis at presentation (P < 0.01) and a CXCR4 H-score >30 (P = 0.04) were significantly associated with reduced survival. Prospective clinical testing of patient tumors identified CXCR4-positivity in 76% of 21 NECs, 67% of 15 lung NETs (including 8 of 10 atypical carcinoids), and 0% of 25 non-lung NETs (including 5 NETS G3s). These data support the hypothesis that CXCR4-targeted theranostics can be utilized effectively for select NETs and NECs.

Head and Neck Cancer Segmentation in FDG PET Images: Performance Comparison of Convolutional Neural Networks and Vision Transformers.

Convolutional neural networks (CNNs) have a proven track record in medical image segmentation. Recently, Vision Transformers were introduced and are gaining popularity for many computer vision applications, including object detection, classification, and segmentation. Machine learning algorithms such as CNNs or Transformers are subject to an inductive bias, which can have a significant impact on the performance of machine learning models. This is especially relevant for medical image segmentation applications where limited training data are available, and a model's inductive bias should help it to generalize well. In this work, we quantitatively assess the performance of two CNN-based networks (U-Net and U-Net-CBAM) and three popular Transformer-based segmentation network architectures (UNETR, TransBTS, and VT-UNet) in the context of HNC lesion segmentation in volumetric [F-18] fluorodeoxyglucose (FDG) PET scans. For performance assessment, 272 FDG PET-CT scans of a clinical trial (ACRIN 6685) were utilized, which includes a total of 650 lesions (primary: 272 and secondary: 378). The image data used are highly diverse and representative for clinical use. For performance analysis, several error metrics were utilized. The achieved Dice coefficient ranged from 0.833 to 0.809 with the best performance being achieved by CNN-based approaches. U-Net-CBAM, which utilizes spatial and channel attention, showed several advantages for smaller lesions compared to the standard U-Net. Furthermore, our results provide some insight regarding the image features relevant for this specific segmentation application. In addition, results highlight the need to utilize primary as well as secondary lesions to derive clinically relevant segmentation performance estimates avoiding biases.

Pre-clinical Evaluation of Biomarkers for Early Detection of Nephrotoxicity Following Alpha-particle Radioligand Therapy.

Purpose: Cancer treatment with alpha-emitter-based radioligand therapies (α-RLTs) demonstrates promising tumor responses. Radiolabeled peptides are filtered through glomeruli, followed by potential reabsorption of a fraction by proximal tubules, which may cause acute kidney injury (AKI) and chronic kidney disease (CKD). Because tubular cells are considered the primary site of radiopeptides' renal reabsorption and potential injury, the current use of kidney biomarkers of glomerular functional loss limits the evaluation of possible nephrotoxicity and its early detection. This study aimed to investigate whether urinary secretion of tubular injury biomarkers could be used as additional non-invasive sensitive diagnostic tool to identify unrecognizable tubular damage and risk of long-term α-RLTs nephrotoxicity. Methods: A bifunctional cyclic peptide, melanocortin ligand-1(MC1L), labeled with [ 203 Pb]Pb-MC1L, was used for [ 212 Pb]Pb-MC1L biodistribution and absorbed dose measurements in CD-1 Elite mice. Mice were treated with [ 212 Pb]Pb-MC1L in a dose escalation study up to levels of radioactivity intended to induce kidney injury. The approach enabled prospective kidney functional and injury biomarker evaluation and late kidney histological analysis to validate these biomarkers. Results: Biodistribution analysis identified [ 212 Pb]Pb-MC1L reabsorption in kidneys with a dose deposition of 2.8, 8.9, and 20 Gy for 0.9, 3.0, and 6.7 MBq injected [ 212 Pb]Pb-MC1L doses, respectively. As expected, mice receiving 6.7 MBq had significant weight loss and CKD evidence based on serum creatinine, cystatin C, and kidney histological alterations 28 weeks after treatment. A dose-dependent urinary Neutrophil gelatinase-associated lipocalin (NGAL, tubular injury biomarker) urinary excretion the day after [ 212 Pb]Pb-MC1L treatment highly correlated with the severity of late tubulointerstitial injury and histological findings. Conclusion: urine NGAL secretion could be a potential early diagnostic tool to identify unrecognized tubular damage and predict long-term α-RLT-related nephrotoxicity.

Radiation Safety Considerations of Household Waste Disposal After Release of Patients Who Have Received [177Lu]Lu-PSMA-617.

Patients with metastatic prostate cancer are more likely than other groups to present for radiopharmaceutical therapy with urinary incontinence due to complications from prior local prostate cancer treatment. A consequence of urinary incontinence in patients receiving radiopharmaceutical therapy is the potential production of contaminated solid waste, which must be managed by the licensee and, at home, managed by and disposed of by the patient. Prolonging the patient stay in the treating facility after radiopharmaceutical therapy administration, until the first urinary void or potentially overnight, may moderately reduce the quantity of contaminated waste being managed by the patient at home. However, this approach does not fully mitigate the need for a patient waste-management strategy. In this brief communication, the relative radiation safety merits of contaminated waste disposal in the normal household waste stream in comparison to other waste management strategies are evaluated.

Assessment of the feasibility of same-day discharge following minimally invasive hysterectomy in the elderly population.

Objective: To determine the safety and feasibility of same-day discharge (SDD) following minimally invasive hysterectomy (MIH) for elderly patients and to evaluate associations between age, frailty, and postoperative outcomes. Methods: Retrospective review was conducted of patients aged ≥ 70 who underwent MIH within a single gynecologic oncology institution from 2018 to 2020. Demographics, peri-operative factors, postoperative complications, and 30-day readmission rates were collected. Frailty was determined by an 11-point modified frailty index ≥ 2. Outcomes were compared between SDD and observation groups using Fisher's exact and Wilcoxon rank-sum tests. Results: Of 169 patients included in the analysis, 8.9% (n = 15) underwent SDD, and 91.1% (n = 154) were admitted for OBS following MIH. Demographics, peri-operative factors, and frailty rates (33% SDD vs 43.5% observation; p = 0.59) were similar between groups. 86.7% (n = 13) of SDD cases were completed before 12PM, and none were completed after 6PM. No SDD patients had early post-operative complications or hospital readmissions. Early postoperative complications were diagnosed in 9 (5.8%) patients admitted for OBS, and the 30-day hospital readmission rate for patients who underwent OBS was 8.4% (n = 13). While elderly patients who met objective frailty criteria (n = 72) did not have a higher likelihood of early post-operative complications (44.4% vs 55.6%; p = 0.909), they did have a higher likelihood of ED visit within 30 days of discharge (15.3 vs 3.1%; p = 0.009), and a trend was noted toward a higher rate of 30-day hospital readmission (12.5% vs 4.1%; p = 0.080). Conclusions: Elderly patients undergoing SDD following MIH did not have increased morbidity or mortality. Elderly patients who meet objective criteria for frailty, however, represent a more vulnerable population.

Effect of Aspirin vs Enoxaparin on 90-Day Mortality in Patients Undergoing Hip or Knee Arthroplasty: A Secondary Analysis of the CRISTAL Cluster Randomized Trial.

Importance: Ischemic heart disease remains the leading cause of mortality following hip and knee arthroplasty. Due to its antiplatelet and cardioprotective properties, aspirin has been proposed as an agent that could reduce mortality when used as venous thromboembolism (VTE) prophylaxis following these procedures. Objective: To compare aspirin with enoxaparin in reducing 90-day mortality for patients undergoing hip or knee arthroplasty procedures. Design, Setting, and Participants: This study was a planned secondary analysis of the CRISTAL cluster randomized, crossover, registry-nested trial performed across 31 participating hospitals in Australia between April 20, 2019, and December 18, 2020. The aim of the CRISTAL trial was to determine whether aspirin was noninferior to enoxaparin in preventing symptomatic VTE following hip or knee arthroplasty. The primary study restricted the analysis to patients undergoing total hip or knee arthroplasty for a diagnosis of osteoarthritis only. This study includes all adult patients (aged ≥18 years) undergoing any hip or knee arthroplasty procedure at participating sites during the course of the trial. Data were analyzed from June 1 to September 6, 2021. Interventions: Hospitals were randomized to administer all patients oral aspirin (100 mg daily) or subcutaneous enoxaparin (40 mg daily) for 35 days after hip arthroplasty and 14 days after knee arthroplasty procedures. Main Outcomes and Measures: The primary outcome was mortality within 90 days. The between-group difference in mortality was estimated using cluster summary methods. Results: A total of 23 458 patients from 31 hospitals were included, with 14 156 patients allocated to aspirin (median [IQR] age, 69 [62-77] years; 7984 [56.4%] female) and 9302 patients allocated to enoxaparin (median [IQR] age, 70 [62-77] years; 5277 [56.7%] female). The mortality rate within 90 days of surgery was 1.67% in the aspirin group and 1.53% in the enoxaparin group (estimated difference, 0.04%; 95% CI, -0.05%-0.42%). For the subgroup of 21 148 patients with a nonfracture diagnosis, the mortality rate was 0.49% in the aspirin group and 0.41% in the enoxaparin group (estimated difference, 0.05%; 95% CI, -0.67% to 0.76%). Conclusions and Relevance: In this secondary analysis of a cluster randomized trial comparing aspirin with enoxaparin following hip or knee arthroplasty, there was no significant between-group difference in mortality within 90 days when either drug was used for VTE prophylaxis. Trial Registration: http://anzctr.org.au Identifier: ACTRN12618001879257.

Obesity is associated with an increased risk of undergoing hip replacement in Australia.

BACKGROUND: Obesity is a known risk factor for the development of hip osteoarthritis. The aim of this study was to investigate whether obesity is associated with the risk of undergoing total hip replacement (THR) in Australia. METHODS: A cohort study was conducted comparing data from the Australian Bureau of Statistics and the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) from 2017 to 2018. Body mass index (BMI) data for patients undergoing primary total hip replacement and resurfacing for osteoarthritis were obtained from the AOANJRR. The distribution of THR patients by BMI category was compared to the general population, in age and sex sub-groups. RESULTS: During the study period, 32 495 primary THR were performed for osteoarthritis in Australia. Compared to the general population, there was a higher prevalence of Class I, II and III obesity in patients undergoing THR in both sexes aged 35-74 years. Class III obese females and males aged 55-64 years were 2.9 and 1.7 times more likely to undergo THR, respectively (P < 0.001). Class III obese females and males underwent THR on average 5.7 and 7.0 years younger than their normal weight counterparts, respectively. CONCLUSION: Obese Australians are at increased risk of undergoing THR, and at a younger age.

Obesity is associated with an increased risk of undergoing shoulder arthroplasty in Australia.

BACKGROUND: The aim of this study was to examine the incidence of overweight and obesity in patients undergoing primary total shoulder arthroplasty (TSA) for osteoarthritis (OA) in Australia compared to the incidence of obesity in the general population. MATERIALS AND METHODS: A 2017/18 cohort consisting of 2997 patients from the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) who underwent TSA were compared with matched controls from the Australian Bureau of Statistics (ABS) National Health Survey from the same time period. The 2 groups were analyzed according to body mass index (BMI) category, sex, and age. RESULTS: According to the 2017/18 National Health Survey, 35.6% of Australian adults were overweight and 31.3% were obese. Of the primary TSA cases performed, 34.9% were overweight and 50.1% were obese. The relative risk of requiring TSA for OA increased with increasing BMI category. Class III obese females, aged 55-64, were 8.6 times more likely to receive a TSA compared to their normal weight counterparts. Males in the same age and BMI category were 2.5 times more likely. Class III obese patients underwent TSA 4 years (female) and 6 years (male) younger than their normal weight counterparts. CONCLUSION: Obesity significantly increases the risk of requiring TSA. The association appears to be particularly strong for younger females.

The association between body mass index and patient-reported outcome measures before and after primary total hip or knee arthroplasty: a registry.

BACKGROUND: The objective is to determine whether body mass index is associated with patient-reported expectations and well-being before primary total hip or total knee arthroplasty, and patient-reported outcomes 6 months after surgery. METHODS: Data were obtained from the Australian Orthopaedic Association National Joint Replacement Registry. Outcome measures included pre-operative expectations for post-operative mobility, joint pain and health, pre- and post-operative EQ-5D-5L, EQ-VAS, Oxford Hip/Knee Scores and joint pain scales, and post-operative perceived change and perceived satisfaction. Associations with BMI were assessed using chi-square tests, analysis of variance and Linear Mixed Models equations. RESULTS: Data were available for 12 816 primary THA patients and 20 253 primary TKA patients. Pre-operatively, patients in higher BMI categories were significantly more likely to expect ongoing problems with mobility, more joint pain and poorer health following surgery (P<0.01 for all analyses). For arthroplasty patients, higher BMI was associated with poorer pre-operative and post-operative scores for all measures. BMI was positively associated with improvements in EQ-5D, OHS/KS and joint pain. While between-group differences were statistically significant, many were small in magnitude. There was no association between BMI and patient-perceived change or satisfaction after arthroplasty. CONCLUSION: Patients undergoing THA/TKA, higher BMI was associated with lower pre-operative expectations, poorer well-being before surgery, and worse scores after surgery. Patients who were obese demonstrated comparable satisfaction with their operated joint, compared with non-obese patients. BMI was associated with greater pre- to post-operative improvements in outcome scores for EQ-5D, VAS knee, OHS/OKS and joint pain but these differences may not be clinically important.

Safety and feasibility of same-day discharge following minimally invasive hysterectomy in the morbidly obese patient population.

OBJECTIVES: To determine whether morbid obesity should serve as an independent factor in the decision for same day discharge following minimally invasive hysterectomy. METHODS: Retrospective review was performed of patients with BMI ≥ 40 who underwent minimally invasive hysterectomy within a single comprehensive cancer center between January 2018 - August 2020. Demographics, perioperative factors, post-operative monitoring, complications, and readmissions were compared between patients who underwent same day discharge and overnight observation using Fisher's exact tests and Wilcoxon rank-sum tests. RESULTS: 374 patients with BMI ≥ 40 were included. Eighty-three (22.2%) patients underwent same day discharge, and 291 (77.8%) patients underwent overnight observation. Factors associated with increased likelihood of same day discharge included younger age (median age 53 vs 58; p = 0.001), lower BMI (median BMI 45 vs 47; p = 0.005), and fewer medical co-morbidities (Charlson Co-Morbidity Index 2 vs 3; p < 0.001). On multivariate regression analysis, frailty (OR 2.16 [1.14-4.11], p = 0.019) and surgical completion time after 12 PM (OR 3.67 [2.16-6.24], p < 0.001) were associated with increased risk of overnight observation. Few patients admitted for routine overnight observation required medical intervention (n = 14, 4.8%); most of these patients were frail (64.3%). The overall hospital readmission rate within 30 days of discharge was 3.2% (n = 12), with no patients discharged on the day of surgery being readmitted. CONCLUSIONS: Morbid obesity alone should not serve as a contraindication to same day discharge following minimally invasive hysterectomy. Admission for observation was associated with low rates of clinically meaningful intervention, and patients who underwent same day discharge were not at increased risk of adverse outcome.

Hip Arthroplasty Outcomes in the Presence of Kidney Failure: A National Data Linkage Study.

BACKGROUND: Patients who have kidney failure are at higher risk of requiring total hip arthroplasty (THA) and are at higher risk of complications. This study compared the rate of revision surgery and mortality following THA between patients who have kidney failure receiving long term dialysis or who had a kidney transplant and those who did not have kidney failure. METHODS: A data linkage study was performed using data from 2 national registries: a registry of dialysis and kidney transplant patients and a registry of THA procedures. Both registries had coverage of almost all procedures or treatments in Australia. Data from September 1999 to December 2016 were used. Mortality and revision surgery were compared between patients receiving dialysis, those who had a functioning kidney transplant, and patients who did not have kidney failure using Cox and Fine-Gray (competing risk) regression models. A total of 383,478 primary THA procedures were identified as people receiving dialysis (n = 490), who had a functioning kidney transplant (n = 459), or who did not have kidney failure (n = 382,529). RESULTS: There was no significant difference in the overall rate of revision surgery between the groups (dialysis versus no kidney failure HR = 1.20; 95% CI 0.76, 1.88, transplant versus no kidney failure (hazard ratio) HR = 1.01; 95% (confidence interval) CI 0.66, 1.53). The risk for death after surgery was significantly higher in the dialysis group compared to both the functioning transplant group (HR = 3.44; 95%CI 1.58, 7.5), and in those without kidney failure (HR = 4.13; 95%CI 3.25, 5.25). CONCLUSION: The rate of mortality after THA in patients on dialysis is higher than in patients who have a functioning transplant or those who do not have kidney failure, but there is no early excess mortality to suggest a difference in this metric due to the surgery.

Clinical and laboratory aspects of condylomata lata lesions of syphilis.

OBJECTIVES: Condylomata lata are a less common but distinctive syphilitic lesion. Variable theories as to their nature and origin exist. The aim of this study was to determine the clinical and laboratory characteristics of condylomata lata by determining (1): the most closely aligned stage of syphilis, based on the rapid plasma reagin (RPR) titre; (2) symptom duration and (3) Treponema pallidum PCR cycle threshold (CT) values, as an indicator of organism load. METHODS: This was a retrospective study of patients with T. pallidum PCR-positive condylomata lata lesions, attending a clinic in Melbourne, Australia, between 2011 and 2021. Syphilis serology was undertaken and RPR titres compared between condylomata lata, primary and secondary syphilis cases. RESULTS: 51 cases with T. pallidum PCR-positive condylomata lata were included. 41 cases were in men, 40 of whom were men who have sex with men (MSM), and 10 in women. Twelve of 51 (24%) cases were in HIV-positive MSM. Thirty-three of 51 (65%) had other mucocutaneous signs of secondary syphilis; 18 (35%) had no other signs of secondary syphilis. The median RPR titre among the 51 condylomata lata cases was 1:128, compared with the median RPR titre of primary syphilis (1:4) and of secondary syphilis (1:128). The median duration of lesions was 24 (IQR 10-60) days, with no significant difference between those with and without other signs of secondary syphilis (p=0.75). Median CT values for condylomata lata (CT=31) and primary syphilis (CT=31) were significantly lower than for other secondary syphilis lesion types (CT=33), indicating higher T. pallidum loads for condylomata lata and primary lesions compared with other secondary syphilis lesion types. DISCUSSION: These findings support condylomata lata as lesions that occur during the secondary stage of syphilis and which are likely to be highly infectious.

Antibiotic utilisation in primary and revision total hip replacement patients: A registry linkage cohort study of 106 253 patients using the Australian Orthopaedic Association National Joint Replacement Registry.

PURPOSE: Infection is a major complication following joint replacement (JR) surgery. However, little data exist regarding antibiotic utilisation following primary JR and how use changes with subsequent revision surgery. This study aimed to examine variation in antibiotic utilisation rates before and after hip replacement surgery in those revised for infection, revised for other reasons and those without revision. METHODS: This retrospective cohort analysis used linked data from the Australian Orthopaedic Association National Joint Replacement Registry and Australian Government Pharmaceutical Benefits Scheme. Patients were included if undergoing total hip replacement (THR) for osteoarthritis in private hospitals between 2002 and 2017. Three groups were examined: primary THR with no subsequent revision (n = 102 577), primary THR with a subsequent revision for reasons other than periprosthetic joint infection (PJI) (n = 3156) and primary THR with a subsequent revision for PJI (n = 520). Monthly antibiotic utilisation rates and prevalence rate ratios (PRRs) with 95% confidence intervals (CIs) were calculated in the 2 years pre- and post-THR. RESULTS: Prior to primary THR antibiotic utilisation was 9%-10%. After primary THR, antibiotic utilisation rates were higher among patients revised for PJI (PRR 1.69, 95% CI 1.60-1.79) compared to non-revised patients, while the utilisation rate was lower in patients revised for reasons other than infection (PRR 0.96, 95% CI 0.93-0.98). For those revised for infection, antibiotic utilisation post-revision surgery was two times higher than those revised for other reasons (PRR 2.16, 95% CI 2.08-2.23). Utilisation of injectable antibiotics including, vancomycin, flucloxacillin and cephazolin was higher in those revised for PJI patients 0-2 weeks following surgery but not in those revised for other reasons compared to the non-revised group. CONCLUSIONS: Ongoing antibiotic utilisation after primary surgery may be an early signal of problems with the THR and should be a prompt for primary care physicians to refer patients to specialists for further appropriate investigations and management.

No increased risk of cancer associated with metal-on-metal or ceramic-on-ceramic procedures compared to other bearing surfaces in patients with total hip arthroplasty: A nationwide linked registry cohort analysis of 167,837 patients.

OBJECTIVES: Studies have identified increased cancer risk among patients undergoing total hip arthroplasty (THA) compared to the general population. However, evidence of all-cause and site-specific cancer risk associated with different bearing surfaces has varied, with previous studies having short latency periods with respect to use of modern Metal-on-Metal (MoM) bearings. Using the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) linked to Australasian Association of Cancer Registries data, our aim was to evaluate risk of all-cause and site-specific cancer according to bearing surfaces in patients undergoing THA for osteoarthritis and whether risk increased with MoM bearings. METHODS: Standardized incidence ratios (SIRs) and 95% confidence intervals (CIs) were calculated by comparing number of observed cancer cases to expected number based on incidence rate in the Australian population. All-cause and site-specific cancer rates were calculated for all conventional stemmed THA (csTHA) and resurfacing THA (rsTHA) procedures performed for osteoarthritis. Cox proportional hazards models were used to compare cancer rates for MoM, ceramic-on-ceramic (CoC) and resurfacing procedures with a comparison group comprising metal-on-polyethylene (MoP) or ceramic-on-polyethylene (CoP) procedures. RESULTS: There were 156,516 patients with csTHA procedures and 11,321 with rsTHA procedures for osteoarthritis performed between 1999 and 2012. Incidence of all-cause cancer was significantly higher for csTHA (SIR 1.24, 95% CI 1.22-1.26) and rsTHA (SIR 1.74, 95% CI 1.39-2.04) compared to the Australian population. For csTHA, there was no significant difference in all-site cancer rates for MoM (Hazard Ratio (HR) 1.01, 95%CI 0.96-1.07) or CoC (HR 0.98, 95%CI 0.94-1.02) compared to MoP and CoP bearings. Significantly increased risk of melanoma, non-Hodgkins lymphoma, myeloma, leukaemia, prostate, colon, bladder and kidney cancer was found for csTHA and, prostate cancer, melanoma for rsTHA procedures when compared to the Australian population, although risk was not significantly different across bearing surfaces. CONCLUSIONS: csTHA and rsTHA procedures were associated with increased cancer incidence compared to the Australian population. However, no excess risk was observed for MoM or CoC procedures compared to other bearing surfaces.