Osteoarthritis (OA) of the hip is the most common indication for total hip replacement (THR). Obesity is a risk factor for the development of OA and has recently resulted in patients requiring THRs at much younger ages to relieve pain at the joint capsule and restore mobility. However, the impact of obesity on THR mortality is not well understood. An updated systematic review was performed to identify whether an obese BMI should influence patient selection for surgery. Specifically, the impact of obesity on short-term mortality, long-term mortality, and peri- and post-operative complications was assessed with a particular focus on BMI classes. A comprehensive literature search of Ovid Medline and EMBASE in November 2022 identified relevant papers in accordance with PRISMA methodology. After removing duplicates, 2988 articles underwent strict inclusion and exclusion criteria, resulting in 12 papers for analysis. There was no statistically significant difference in mortality risk between obese and non-obese populations. Obesity was associated with a lower risk of short-term mortality than in the normal weight control group, however there was an increased mortality risk in obese patients long-term likely due to comorbidities. Obese patients were significantly younger than normal BMI and underweight patients. However, the paper found increased mortality risk in underweight and morbidly obese patients. Obese patients did not have an increased risk of mortality when compared to non-obese patients following THR. Obesity may have a protective effect on mortality up to a BMI of 40kg/m2, although this may be influenced by the obesity paradox which states only the healthiest obese individuals are selected for surgery, which could attribute to a lower mortality risk. The greatest risk of mortality and complication was associated with underweight patients. As a result, a BMI greater than 30kg/m2 may not necessitate a hip replacement contraindication. It is important surgeons apply careful consideration and comprehensive risk assessment on patients who require a THR, especially at the BMI extremes

OpenPredictor, a machine learning-enabled clinical decision aid, has been developed to manage backlogs in elective surgeries. It aims to optimise the use of high volume, low complexity surgical pathways by accurately stratifying patient risk, thereby facilitating the allocation of patients to the most suitable surgical sites. The tool augments elective surgical pathways by providing automated secondary opinions for perioperative risk assessments, enhancing decision-making. Its primary application is in elective sites utilising lighter pre-assessment methods, identifying patients with minimal complication risks and those high-risk individuals who may benefit from early pre-assessment. The Phase 1 clinical evaluation of OpenPredictor entailed a prospective analysis of 156 patient records from elective hip and knee joint replacement surgeries. Using a polynomial logistic regression model, patients were categorised into high, moderate, and low-risk groups. This categorisation incorporated data from various sources, including patient demographics, co-morbidities, blood tests, and overall health status. In identifying patients at risk of postoperative complications, OpenPredictor demonstrated parity with consultant-led preoperative assessments. It accurately flagged 70% of patients who later experienced complications as moderate or high risk. The tool's efficiency in risk prediction was evidenced by its balanced accuracy (75.6%), sensitivity (70% with a 95% confidence interval of 62.05% to 76.91%), and a high negative predictive value (96.7%). OpenPredictor presents a scalable and consistent solution for managing elective surgery pathways, comparable in performance to secondary consultant opinions. Its integration into pre-assessment workflows assists in efficient patient categorisation, reduces late surgery cancellations, and optimises resource allocation. The Phase 1 evaluation of OpenPredictor underscores its potential for broader clinical application and highlights the need for ongoing data refinement and system integration to enhance its performance

Aims. To develop and externally validate a parsimonious statistical prediction model of 90-day mortality after elective total hip arthroplasty (THA), and to provide a web calculator for clinical usage. Methods. We included 53,099 patients with cemented THA due to osteoarthritis from the Swedish Hip Arthroplasty Registry for model derivation and internal validation, as well as 125,428 patients from England and Wales recorded in the National Joint Register for England, Wales, Northern Ireland, the Isle of Man, and the States of Guernsey (NJR) for external model validation. A model was developed using a bootstrap ranking procedure with a least absolute shrinkage and selection operator (LASSO) logistic regression model combined with piecewise linear regression. Discriminative ability was evaluated by the area under the receiver operating characteristic curve (AUC). Calibration belt plots were used to assess model calibration. Results. A main effects model combining age, sex, American Society for Anesthesiologists (ASA) class, the presence of cancer, diseases of the central nervous system, kidney disease, and diagnosed obesity had good discrimination, both internally (AUC = 0.78, 95% confidence interval (CI) 0.75 to 0.81) and externally (AUC = 0.75, 95% CI 0.73 to 0.76). This model was superior to traditional models based on the Charlson (AUC = 0.66, 95% CI 0.62 to 0.70) and Elixhauser (AUC = 0.64, 95% CI 0.59 to 0.68) comorbidity indices. The model was well calibrated for predicted probabilities up to 5%. Conclusion. We developed a parsimonious model that may facilitate individualized risk assessment prior to one of the most common surgical interventions. We have published a web calculator to aid clinical decision-making. Cite this article: Bone Joint J 2021;103-B(3):469–478

Introduction. Instability remains a common complication following total hip arthroplasty (THA) and continues to account for the highest percentage of revisions in numerous registries. Many risk factors have been described, yet a patient-specific risk assessment tool remains elusive. The purpose of this study was to apply a machine learning algorithm to develop a patient-specific risk score capable of dynamic adjustment based on operative decisions. Methods. 22,086 THA performed between 1998–2018 were evaluated. 632 THA sustained a postoperative dislocation (2.9%). Patients were robustly characterized based on non-modifiable factors: demographics, THA indication, spinal disease, spine surgery, neurologic disease, connective tissue disease; and modifiable operative decisions: surgical approach, femoral head size, acetabular liner (standard/elevated/constrained/dual-mobility). Models were built with a binary outcome (event/no event) at 1-year and 5-year postoperatively. Inverse Probability Censoring Weighting accounted for censoring bias. An ensemble algorithm was created that included Generalized Linear Model, Generalized Additive Model, Lasso Penalized Regression, Kernel-Based Support Vector Machines, Random Forest and Optimized Gradient Boosting Machine. Convex combination of weights minimized the negative binomial log-likelihood loss function. Ten-fold cross-validation accounted for the rarity of dislocation events. Results. The 1-year model achieved an area under the curve (AUC)=0.63, sensitivity=70%, specificity=50%, positive predictive value (PPV)=3% and negative predictive value (NPV)=99%. The 5-year model achieved an AUC=0.62, sensitivity=69%, specificity=51%, PPV=7% and NPV=97%. All cohort-level accuracy metrics performed better than chance. The two most influential predictors in the model were surgical approach and acetabular liner. Conclusions. This machine learning algorithm demonstrates high sensitivity and NPV, suggesting screening tool utility. The model is strengthened by a multivariable dataset portending differential dislocation risk. Two modifiable variables (approach and acetabular liner) were the most influential in dislocation risk. Calculator utilization in “app” form could enable individualized risk prognostication. Furthermore, algorithm development through machine learning facilitates perpetual model performance enhancement with future data input

Introduction. Inpatient rehabilitation services following joint replacement have been estimated to cost over $3 billion/ yr. A shift in reimbursement strategies to bundle payments with the goal of decreasing cost and improving quality has given discharge disposition after joint replacement a front row seat. Our objectives were (1) to establish a correlation between the accuracy of current tools utilized to predict discharge location and (2) compare preoperative and postoperative patient oriented outcomes (POO's) according to discharge disposition. Methods. 188 consecutive total hip arthroplasty (THA) surgeries performed by a single surgeon were prospectively studied. Pre-intervention assessment of the probable and preferred discharge disposition was performed using one of 5 tools (1) experienced surgical coordinator evaluation (2) Risk Assessment and Prediction Tool (RAPT); (3) Charlson Score; (4) ASA Score; and (5) Patient Self-Reported Health Status. Demographic characteristics, Visual Analogue Scale, QWB-7, SF-36, WOMAC, clinical scores were recorded before and after surgery. Correlation between final discharge disposition (home vs rehab) and its predictors was performed. Preoperative and postoperative outcomes were compared, p<0.05 was considered significant. Results. Most accurate predictor of discharge disposition was determined by our experienced surgical coordinator (OR: 11.05; 95% CI of 2.21 to 55.32; p<0.001), followed by the RAPT (OR: 1.56; 95% CI of 1.29 to 1.90; p=0.01). We found a significant difference in age (Rehab: 72.4 SE 1.2 vs Home: 70.3 SE 1.0; p=0.01) and length of stay (Rehab: 3.6 SE 0.01 vs Home: 3.14 SE 0.07; p<0.001) between those discharged to rehab than those discharged home. Mean follow-up time was 2.22 years (range 1–4 years). There was a significant difference between groups on most outcome measures preoperatively (rehab worse than home; p<0.001). Both groups demonstrated significant improvement in all patient perceived outcome measures after THA, but those discharged to rehab continue to report worse scores for the QWB (Rehab: 0.62 SE 0.02 vs Home: 0.67 SE 0.01; p=0.02) and Hip Harris Score (Rehab: 83.07 SE 1.75 vs Home: 88.65 SE 1.31; p=0.01). Discussion. Clinical intuition and personal interaction proved to be the best predictor for discharge disposition. Worse outcomes were observed in patients being discharged to rehab. For any tables or figures, please contact the authors directly

Aims

Osteoporosis is common in total hip arthroplasty (THA) patients. It plays a substantial factor in the surgery’s outcome, and previous studies have revealed that pharmacological treatment for osteoporosis influences implant survival rate. The purpose of this study was to examine the prevalence of and treatment rates for osteoporosis prior to THA, and to explore differences in osteoporosis-related biomarkers between patients treated and untreated for osteoporosis.

Aims. Increasingly, patients with bilateral hip arthritis wish to undergo staged total hip arthroplasty (THA). With the rise in demand for arthroplasty, perioperative risk assessment and counselling is crucial for shared decision making. However, it is unknown if complications that occur after a unilateral hip arthroplasty predict complications following surgery of the contralateral hip. Patients and Methods. We used nationwide linked discharge data from the Healthcare Cost and Utilization Project between 2005 and 2014 to analyze the incidence and recurrence of complications following the first- and second-stage operations in staged bilateral total hip arthroplasty (BTHAs). Complications included perioperative medical adverse events within 30 to 60 days, and infection and mechanical complications within one year. Conditional probabilities and odds ratios (ORs) were calculated to determine whether experiencing a complication after the first stage of surgery increased the risk of developing the same complication after the second stage. Results. A total of 13 829 patients (5790 men and 8039 women) who underwent staged BTHAs were analyzed. The mean age at first operation was 62.9 years (14 to 95). For eight of the 12 outcomes evaluated, patients who experienced the outcome following the first arthroplasty had a significantly increased probability and odds of developing that same complication following the second arthroplasty, compared with those who did not experience the complication after the first surgery. This was true for digestive complications (OR 25.67, 95% confidence interval (CI) 13.86 to 46.08; p < 0.001), urinary complications (OR 6.48, 95% CI 1.7 to 20.73; p = 0.01), haematoma (OR 12.17, 95% CI 4.55 to 31.14; p < 0.001), deep vein thrombosis (OR 4.82, 95% CI 2.34 to 9.65; p < 0.001), pulmonary embolism (OR 12.03, 95% CI 2.02 to 46.77; p = 0.01), deep hip infection (OR 534.21, 95% CI 314.96 to 909.25; p < 0.001), superficial hip infection (OR 1574.99, 95% CI 269.83 to 9291.81; p < 0.001), and mechanical malfunction (OR 117.49, 95% CI 91.55 to 150.34; p < 0.001). Conclusion. The occurrence of certain complications after unilateral THA is associated with an increased risk of the same complication occurring after staged arthroplasty of the contralateral hip. Patients who experience these complications after unilateral hip arthroplasty should be appropriately counselled regarding their risk profile prior to undergoing staged contralateral hip arthroplasty. Cite this article: Bone Joint J 2019;101-B(6 Supple B):77–83

Aims

Spinopelvic pathology increases the risk for instability following total hip arthroplasty (THA), yet few studies have evaluated how pathology varies with age or sex. The aims of this study were: 1) to report differences in spinopelvic parameters with advancing age and between the sexes; and 2) to determine variation in the prevalence of THA instability risk factors with advancing age.

Aims

The volume of ambulatory total hip arthroplasty (THA) procedures is increasing due to the emphasis on value-based care. The purpose of the study is to identify the causes for failed same-day discharge (SDD) and perioperative factors leading to failed SDD.

Introduction. Increasingly, patients with bilateral hip arthritis wish to undergo staged total hip arthroplasty. With the rise in demand for arthroplasty perioperative risk assessment and counseling is critical for shared decision making; however, it is unknown if complications that occur after a unilateral hip arthroplasty predict complications following surgery of the contralateral hip. Methods. We used nation-wide linked discharge data from the Hospital Cost and Utilization Project from 2005–2014 to analyze the incidence and recurrence of complications following the first and second stage operations in staged bilateral total hip arthroplasty (BTHAs). Complications included perioperative risks within 30–60 days, and infection and mechanical complications within one year. Conditional probabilities and odds ratios were calculated to determine whether experiencing a complication after the first stage of surgery increased the risk of developing the same complication after the second stage. Results. 13,829 patients who underwent staged BTHAs were analyzed. For 6 of the 11 outcomes evaluated, patients who experienced the outcome following the first arthroplasty had a significantly increased probability and odds of developing that same complication following the second arthroplasty, compared to those who did not experience the complication after the first surgery. This was true for digestive complications (OR=25.67, 95% CI=13.86–46.08, p<0.001), hematoma (OR=12.17, 95% CI=4.55–31.14, p<0.001), deep vein thrombosis (OR=4.82, 95% CI=2.34–9.65, p<0.001), pulmonary embolism (OR=12.03, 95% CI=2.02–46.77, p=0.01), hip infection (OR=2439.48, 95% CI=836.73–6759.85, p<0.001), and mechanical malfunction (OR=117.49, 95% CI=91.55–150.34, p<0.001). Conclusions. The occurrence of certain complications after unilateral total hip arthroplasty is associated with an increased risk that the same complication will occur after staged replacement of the contralateral hip. Patients who experience these complications after unilateral hip arthroplasty should be appropriately counseled regarding their risk profile prior to undergoing staged contralateral hip arthroplasty. Level of Evidence: Therapeutic Level III. Keywords: hip arthroplasty; bilateral; staged; joint replacement

The risk of dying following total hip replacement (THR) is low and has declined over the last decades. The influence of comorbidities and worse physical status on mortality leads to the idea that patient-reported health status may also be a predictor of mortality. Although this has not been demonstrated in THR surgery, some studies in other fields have reported an association. The aim of this study was to investigate the relationship between patient-reported health status before THR and the risk of dying up to 5 years post-operatively. The Swedish Hip Arthroplasty Register runs a nationwide PROMs program including the EQ-5D questionnaire to routinely monitor patients undergoing THR in Sweden. For these analyses, we used register data on 42,862 patients with hip osteoarthritis operated with THR between 2008 and 2012. Relative survival ratio was calculated by dividing the observed survival in the patient group by age- and gender-adjusted expected survival of the general population. Multivariable modelling proceeded with time-transformed Cox proportional hazards. Pre-operative responses to the five EQ-5D dimensions along with age, gender, education status, year of surgery, and hospital type were used as independent variables. As a group THR patients had a better survival than the general population. Broken down by the five EQ-5D dimensions we observed differentiated survival patters. For all dimensions, those reporting moderate problems (level 2) had higher mortality than those reporting no problems (level 1) and those reporting extreme problems (level 3) had higher mortality than those reporting level 1 or 2. Worse health status according to the EQ-5D before THR is associated with higher mortality up to five years after surgery. The complexity of the interactions between different patient-factors associated with outcomes complicates accurate assessments of risks and expected benefits for individual patients. EQ-5D responses may be useful in a multifactorial individualized risk assessment before THR

Aims

Type 2 diabetes mellitus (T2DM) impairs bone strength and is a significant risk factor for hip fracture, yet currently there is no reliable tool to assess this risk. Most risk stratification methods rely on bone mineral density, which is not impaired by diabetes, rendering current tests ineffective. CT-based finite element analysis (CTFEA) calculates the mechanical response of bone to load and uses the yield strain, which is reduced in T2DM patients, to measure bone strength. The purpose of this feasibility study was to examine whether CTFEA could be used to assess the hip fracture risk for T2DM patients.

Aims

Our rural orthopaedic service has undergone service restructure during the COVID-19 pandemic in order to sustain hip fracture care. All adult trauma care has been centralised to the Royal Shrewsbury Hospital for assessment and medical input, before transferring those requiring operative intervention to the Robert Jones and Agnes Hunt Orthopaedic Hospital. We aim to review the impact of COVID-19 on hip fracture workload and service changes upon management of hip fractures.

Aims

Thresholds for operative eligibility based on body mass index (BMI) alone may restrict patient access to the benefits of arthroplasty. The purpose of this study was to evaluate the relationship between BMI and improvements in patient-reported outcome measures (PROMs), and to determine how many patients would have been denied improvements in PROMs if BMI cut-offs were to be implemented.

Objectives

Modern metal-on-metal (MoM) hip resurfacing arthroplasty (HRA), while achieving good results with well-orientated, well-designed components in ideal patients, is contraindicated in women, men with head size under 50 mm, or metal hypersensitivity. These patients currently have no access to the benefits of HRA. Highly crosslinked polyethylene (XLPE) has demonstrated clinical success in total hip arthroplasty (THA) and, when used in HRA, potentially reduces metal ion-related sequelae. We report the early performance of HRA using a direct-to-bone cementless mono-bloc XLPE component coupled with a cobalt-chrome femoral head, in the patient group for whom HRA is currently contraindicated.

Aims

To examine incidence of complications associated with outpatient total hip arthroplasty (THA), and to see if medical comorbidities are associated with complications or extended length of stay.