bluuebunny/crossref_metadata_2025 huggingface dataset:
Asset Pricing with Costly Short Sales
Authors: Hugonnier Julien , Prieto Rodolfo
Published: August 2024

We study a dynamic general equilibrium model with costly-to-short stocks and heterogeneous beliefs. Costly short sales drive a wedge between the valuation of assets that promise identical cash flows but that are subject to different trading arrangements. In particular, we show that the price of an asset is given by the risk-adjusted present value of its future cash flows, which include both dividends and an endogenous lending yield that we characterize explicitly. This valuation formula implies that stocks with low and high shorting costs should offer similar risk-return trade-off once returns are appropriately adjusted for lending revenues and thus, sheds light on recent empirical findings about the explanatory power of shorting costs in the cross-section of returns.

This paper was accepted by Lukas Schmid, finance.

Supplemental Material: The data files are available at https://doi.org/10.1287/mnsc.2023.01887 .
Employee Attrition Prediction using Machine Learning in Rolling Stock Manufacturing Company
Authors: Itqon Mu’ammar , Purnomo Jerry Dwi Trijoyo
Published: August 2024

Employee retention is crucial in human resource management, particularly in the rolling stock industry, characterized by a dynamic working environment and fierce competition. Elevated attrition rates can incur heightened recruitment expenses, productivity decline, and institutional knowledge loss. Addressing these concerns, this research endeavors to construct precise predictive models pinpointing employees at a heightened attrition risk. Employing the Team Data Science Process (TDSP) framework, three distinct machine learning algorithms were leveraged: Logistic Regression (LR), Naive Bayes (NB), and Random Forest (RF) to structure the employee dataset. TDSP procedure encompasses stages from data acquisition cleansing to descriptive analysis, dataset partitioning, algorithm deployment, and model appraisal. The evaluated variables include job designation, employment type, marital and educational status, gender, tenure, commute distance, and age. Model effectiveness was gauged via precision, recall, F1-score, and overall accuracy. The Random Forest algorithm surpassed its counterparts, boasting a remarkable accuracy of 93.1%. SHAP (SHapley Additive exPlanations) was incorporated for profound comprehension and model transparency. This analysis accentuated job role and employment type as pivotal in attrition forecasting. Such insights are instrumental for rolling stock firms to discern core determinants and craft potent, data-centric retention approaches.
Decision Making of Diesel Power Plant Hybridization Method of Selat Nasik Diesel Power Plant in Belitung Island Using AHP-VIKOR
Authors: Ocniza Dony , Ciptomulyono Udisubakti
Published: August 2024

The selection of best hybridization methods scenario of Diesel Power Plant or HRES (Hybridization Renewable Energy System) requires not only a good analysis of techno-economic criteria but also many other criteria such as land availability, energy sources availability, and so on. Considering the complexity of criteria involved in the selection of hybridization methods, Multi-Criteria Decision Making (MCDM) is commonly used to evaluate problems with multiple criteria that often have conflicting interests. The HOMER software was used as the basis for conducting techno-economic analysis of various hybridization scenarios that would be applied to the Selat Nasik Diesel Power Plant. Then, an FGD expert was conducted to validate and determine the important criteria for selecting hybridization method scenarios. A pairwise questionnaire were filled out by 5 (five) experts, and then the criteria were weighted using the Analytic Hierarchy Process (AHP). The obtained criteria weights then used by experts to assess several hybridization scenario options, and their rankings were determined using VIKOR. In this research, 17 sub-criteria were identified and categorized into 3 criteria: Technical and Design-Oriented Criteria (Lifespan of HRES, Energy Resources Sustainability, and Potential Power Generation), Financial-Oriented Criteria (CAPEX, O&M Cost, NPV, LCOE, and Diesel Fuel Consumption), and Socio-economic and Environment- Oriented Criteria (GHG Emission, Land Acquisition, Effect on Ecosystem (Animal and Nature Protection), Force Majeure, Noise Pollution, Prospective Jobs and Economic Growth, Political and Regulatory Aspect, Public Awareness Level, and Tradition and Cultural Heritage). Top three sub- criteria with the highest weights were selected: Energy Resources Sustainability (weight 0.408), LCOE (weight 0.096), and CAPEX (weight 0.087). Scenario 1 (S1 (Diesel, PV, Battery)) was chosen as the first-rank scenario (the best scenario) followed by S2 (PV, Battery), S3 (Wind Turbine, PV, Battery), and S4 (Diesel, Wind Turbine, Battery).
Living with parasites: exploiting tolerance of infection to reduce the impact of gastrointestinal nematodes in sheep
Authors: Hayward Adam D , Beal Phoebe AC
Published: August 2024

Gastrointestinal nematodes are among the most prevalent and damaging infections faced by ruminant livestock. Anthelmintic resistance means that sustainable control is essential and selective breeding has been part of this for decades. Breeding, however, has focused on promoting resistance to infection, yet almost no empirical work has been done on the other means by which hosts mitigate the impact of parasites, namely tolerance of infection. This review defines the concepts of resilience, resistance and tolerance, with particular attention to gastrointestinal nematode infections of sheep. How selection has thus far been implemented is discussed, and the pros and cons of each trait are evaluated. Tolerance has been almost completely neglected in livestock science, and its potential mechanisms with regard to gastrointestinal nematodes in sheep are discussed. The authors' work to understand more about tolerance to gastrointestinal nematodes and its potential role in sustainable control of gastrointestinal nematodes in the future is also disscussed.
Control of infectious bovine rhinotracheitis
Authors: Guelbenzu Maria
Published: August 2024

Infectious bovine rhinotracheitis (IBR) is a highly infectious disease of domestic and wild ruminants caused by bovine alphaherpesvirus 1 (BoHV-1). Infectious bovine rhinotracheitis has worldwide distribution with the exception of a limited number of countries which have successfully eradicated it. This article describes the disease caused by BoHV-1, its diagnosis and control, and eradication at herd and European level.
A veterinary nurse's guide to the Modified Glasgow Coma Scale
Authors: Bell Samantha
Published: August 2024

The Modified Glasgow Coma Scale is a resource that was developed to assess and monitor patients with altered neurological status. It incorporates three categories of examination: level of consciousness; motor activity; and brain stem reflexes. Each category is assigned a score from 1–6 and scores are added together giving an overall score of between 3–18. The lower the score, the poorer the prognosis. Scores should be taken at several intervals over a period of time which will provide a trend which gives crucial information to the veterinary team to aid in clinical decision making. The ability to accurately perform the assessment and interpret the results is a skill veterinary nurses can become proficient at and therefore be able to accurately report and discuss patient progress with the veterinary team and clients.
Assessing chronic pain in rabbits
Authors: Morrison Cassie
Published: August 2024

Having worked in practice for nearly a decade, the author developed a passion for rabbit welfare, husbandry and medicine. The author researched how clients view chronic pain in their pet rabbits, how chronic pain in rabbits can be measured and how this may affect routine health checks of rabbits.
LONG-TERM RESULTS OF 331 TWO-STAGE EXCHANGES FOR PERIPROSTHETIC JOINT INFECTION FOLLOWING TOTAL HIP ARTHROPLASTY: LOW REINFECTION AND MECHANICAL FAILURE RATES AT TEN YEARS
Authors: Terhune E. B. , Carstens M. F. , Fruth K. M. , Hannon C. P. , Bedard N. A. , Berry D. J. , Abdel M. P.
Published: August 2024

The relative advantages and disadvantages of two-stage versus one-stage management of infected total hip arthroplasties are the current subject of intense debate. To understand the merits of each approach detailed information on the short and, importantly, longer-term outcomes of each must be known. The purpose of this study was to assess the long-term results of two-stage exchange arthroplasty for THAs in one of the largest series to date.

We identified 331 infected THAs treated with a two-stage exchange arthroplasty between 1993 and 2021 at a single institution. Patients were excluded if they had prior treatment for infection. Mean age at reimplantation was 66 years, 38% were female, and mean BMI was 30 kg/m2. PJI diagnosis was based on the 2011 MSIS criteria. A competing risk model accounting for death was utilized. Mean follow up was 8 years.

The cumulative incidence of reinfection was 7% at 1 year and 11% at 5 and 10 years. Factors predictive of reinfection included BMI>30 kg/m2 (HR 2; p=0.049), and need for a spacer exchange (HR 3.2; p=0.006). The cumulative incidence of any revision was 13% at 5 and 10 years. The cumulative incidence of aseptic revision was 3% at 1 year, 7% at 5 years, and 8% at 10 years. Dislocation occurred in 33 hips (11% at 10 years; 45% required revision). Factors predictive of dislocation were female sex (HR 2; p=0.047) and BMI<30 kg/m2 (HR 3; p=0.02). The mean HHS improved from 54 to 75 at 10 years.

In this series of 331 two-stage exchange arthroplasties performed for infected hips, we found a low aseptic revision rate (8%) and a low rate of reinfection (11%) at 10 years. These long-term mechanical and infection data must be kept in mind when considering a paradigm shift to one-stage exchanges.

Level of Evidence: Level III
A COMPARATIVE ANALYSIS OF 1.5-STAGE AND TWO-STAGE REVISION FOR PERIPROSTHETIC JOINT INFECTION AFTER TOTAL HIP ARTHROPLASTY: IS 1.5-STAGE REALLY EQUIVALENT?
Authors: Hosseinzadeh S. , Rajschmir K. , Villa J. M. , Manrique J. , Riesgo A. M. , Higuera C. A.
Published: August 2024

Two-stage exchange arthroplasty is traditionally used to treat periprosthetic hip infection. Nevertheless, particularly in high-risk patients, there has been increased attention towards alternatives such as 1.5-stage exchange arthroplasty which takes place in one surgery. Therefore, we sought to compare (1) operative time, length-of-stay (LOS), transfusions, (2) causative organism identification and polymicrobial infection rates, (3) re-revision rates and re-revision reasons, (4) mortality, and determine (5) independent predictors of re-revision.

Retrospective chart review of 71 patients who underwent either 1.5- (n=38) or 2-stage (n=33) exchange hip arthroplasty at a single institution (03/2019-05/2023). Demographics, surgical, inpatient, and infection characteristics were noted. Main outcomes evaluated were re-revision rates, re-revision reasons, mortality, and cause of death. Independent predictors of re-revision were assessed utilizing logistic regression. Mean follow: 675 days (range, 23–1,715).

Demographics were not significantly different except for a higher proportion of 1.5-stage patients classified as American-Society-of-Anesthesiologists (ASA) status 3 or 4 (84.2 vs. 48.5%, p=0.002). Length of follow-up was significantly longer in the 2-stage group (924.4 vs. 458 days, p<0.001) as well as operative time (506 vs. 271 minutes, p<0.001). In the 1.5-stage group, there was a higher proportion of polymicrobial infections (23.7 vs. 3.0%, p=0.016), re-revision rates (28.9 vs. 9.1%, p=0.042) and periprosthetic infections as a cause of revision (90.9 vs. 0%, p=0.007). Mortality rates were not significantly different, and no patient died for causes related to infection. Type of surgery (1.5-stage vs. 2-stage) was the only independent predictor of re-revision (odds-ratio 4.0, 95% confidence-interval 1.02–16.16, p=0.046).

Our data suggests that patients who undergo 1.5-stage exchange arthroplasty have a significantly higher re-revision rate (mostly due to infection) when compared to 2-stage patients. We acknowledge potential benefits of the 1.5-stage strategy, especially in high-risk patients since it involves single surgery. However, higher re-revision rates must be considered when counseling patients.
INTRA-ARTICULAR ANTIBIOTICS FOLLOWING SINGLE-STAGE REVISION FOR PERIPROSTHETIC JOINT INFECTION IN CEMENTLESS TOTAL HIP ARTHROPLASTY ARE EFFECTIVE AND SAFE
Authors: Gevers M. , Vandeputte F.-J. , Welters H. , Corten K.
Published: August 2024

High doses of intra-articular (IA) antibiotics has been shown to effectively achieve a minimal biofilm eradication concentration which could mitigate the need for removal of infected but well-ingrown cementless components of a total hip arthroplasty (THA). However, there are concerns that percutaneous catheters could lead to multi-resistance or multi-organism peri-prosthetic joint infections (PJI) following single stage THA revisions for PJI.

Eighteen single-stage revision procedures were performed for acute (N=9) or chronic (N=9) PJI following a primary (N=12) or revision (N=6) cementless THA. Modular and loosened components were replaced. All well ingrown components were retained. Two Hickmann catheters were placed in the joint space. Along with intravenous antibiotics, IA antibiotics were injected twice a day for two weeks, followed by 3 months of oral antibiotics.

Per-operative cultures demonstrated 4 multi-bacterial PJIs. None of the patients developed post-operatively an AB related renal or systemic dysfunction. At a mean follow-up of 38 months [range, 8–72] all patients had normal erythrocyte sedimentation rate and white blood cell count. Four had a slightly elevated C-reactive protein but were completely symptom free and did not show any sign of loosening at a mean of 27 months [range, 16–59].

Addition of high doses of IA antibiotics following single-stage revision for PJI in cementless THA, is an effective and safe treatment option that allows for retention of well-ingrown components. We found no evidence for residual implant infection or catheter induced multi-resistance.

Total hip arthroplasty, revision surgery, Periprosthetic Joint Infection, Intra-articular antibiotics

Level 4 (Case series)
PREVENTION OF PERIPROSTHETIC JOINT INFECTION THROUGH ELECTROPHORETIC DEPOSITION OF GENTAMICIN INTO TITANIUM NANOTUBES: AN IN VIVO INVESTIGATION
Authors: Hamilton J. L. , Gianotti S. , Impergre A. , AbuAlia M. , Markovics A. , Jacobs J. J. , Valle C. J. Della , Wimmer M. A.
Published: August 2024

We created TiO2 nanotubes (TNTs) on the surface of titanium (Ti) implants with subsequential loading with gentamicin and chitosan, acting as a control release agent, by electrophoretic deposition (EPD). We hypothesized femoral implants with TNTs loaded with gentamicin and chitosan would localize antibiotic to the implant and surgical site and prevent PJI in a mouse model.

Ti-6Al-4V ELI wires underwent TNT surface modification by two-step anodization. EPD was then used to load gentamicin and chitosan onto the Ti wire with surface TNTs. Control Ti wires contained TNTs with EPD of chitosan only. 12-week-old male C57BL/6J mice underwent received a right femoral intramedullary implant followed by inoculation at the surgical site with 1×103 CFUs of bioluminescent Xen36 Staphylococcus aureus (S. aureus). Mice were randomly divided into two implant groups: 1) Gentamicin + Chitosan Group (n=7; experimental group); 2) Chitosan Group (n=7; control group). Outcomes included: 1) Relative S. aureus abundance by bioluminescence imaging; 2) Quantification of S. aureus at the implant and surrounding tissue by colony forming unit (CFU) analysis; 3) Scanning electron microscopy (SEM) for implant bacterial biofilm; 4) Radiographic signs of PJI.

Over 14 days assessment following wire implantation and inoculation with S. aureus, the experimental group had no evidence of infection based on i) no increased Xen36 S. aureus bioluminescence signal and ii) no CFUs present. All control had increased bioluminescence signal, above baseline, at all time-points and presence of CFUs.

Ti femoral implants modified with surface TNTs and coated with gentamicin and chitosan through EPD prevented PJI in all mice through 14 days. In comparison, all control mice demonstrated evidence of PJI over 14 days. Implants with TNTs and EPD of gentamicin were highly effective in this mouse PJI model.
THE COMBINED USE OF SINGLE- AND DUAL-MOBILITY CUPS IN PRIMARY TOTAL HIP ARTHROPLASTY IS SAFE IN A UNIVERSITY HOSPITAL PRACTICE
Authors: Argenson J.-N. , Peuchot H. , Simmons E. Haynes , Fabre-Aubrespy M. , Jacquet C. , Flecher X.
Published: August 2024

Dislocation after Total Hip Arthroplasty (THA) is a frequent cause of revision and patients with intrinsic risk factors have been identified. The use of dual mobility (DM) cup has shown great efficiency in preventing dislocation, with questions regarding selective or absolute use. The aim of this study was to compare the outcome of single mobility THA (SM-THA) and DM-THA, when used for selected patients.

This retrospective continuous cohort study evaluated 490 patients of whom 275 received SM-THA and 215 received DM-THA. There were 304 primary osteoarthritis (62%), 121 femoral neck fractures (24%) and 65 other indications (14%). The surgical approach was anterior (AA) in 79% and posterior (PA) in 21% of cases. In the DM-THA group, 189 patients (87%) presented at least one dislocation risk factor compared to 128 patients (46%) in the SM-THA group. The primary outcome was revision for all causes, with or without implant removal. Secondary outcomes included length of hospital stay.

There was no difference in all cause revision at two years follow up with 9 procedures (3.2%) in SM-THA group and 11 in DM-THA group (5.1%) (p=0.3). There were 3 dislocations in SM-THA group (3 AA) and 3 in DM-THA group (2 PA and 1 AA) (p=0.4).

The length of stay was significantly longer in DM-THA group with 7 days (2–12) compared to 4 days (1–7) in SM-THA group (p=0.001).

SM-THA and DM-THA are two complementary devices in the management of patients requiring primary THA. SM-THA is a safe option for patients without dislocation risk factors, especially when using AA. The identification of such factors is important to select patients requiring DM-THA and provide reproducible outcomes in a University Hospital practice including various levels of surgeon experience.
TOTAL HIP ARTHROPLASTY IN CHILDREN DELIVERS LARGE IMPROVEMENTS IN HIP FUNCTION AND QUALITY OF LIFE: A SINGLE-CENTRE COHORT STUDY WITH 34 YEARS OF FOLLOW-UP
Authors: Lamb J. N. , Johnson R. , Siney P. , Wroblewski B. M. , Barrow J. , Divecha H. , Board T. N.
Published: August 2024

The benefits of total hip arthroplasty (THA) may be significantly magnified in children, since the improvement in quality of life has a far greater exposure time and occurs during key developmental stages which may help to maximise lifetime achievement. The purpose of this study is to describe implant survival and patient reported outcomes (PROMS) in a cohort of children following THA.

Retrospective cohort review of all patients treated with THA in a single centre. Routine data analysis did not require ethical approval.

Survival was estimated using Kaplan-Meier and PROMs were recorded (EQ5D-S, Oxford hip score and modified Harris Hip Score) in a sub-group of patients.

66 hips in 47 patients with a median age of 16 years (range 10 to 19 years) underwent THA between 1971 and 2023. 57% (38/68) patients were female, the commonest indications were Mucopolysaccharidoses n = 15, Stills disease (n=15), and Avascular necrosis (n=12). 27 (41%) of constructs were cemented, 5 (8%) were hybrid, and 34 (51%) were cementless. 30 stems were custom made cementless stems.

Median follow up was 3.8 years (range 0–34 years). Implant survival was 87% at 10 years, 61.6% at 20 years and 52.8% at 30 years.

PROMS demonstrated mean preoperative OHS was 12, preoperative MHHS was 23 and EQ5Ds VAS of 38. PROMS improved steadily overtime with mean OHS of 43, MMHS of 75 and EQ5Ds VAS of 89 at one year.

THA was associated with a very large change in patient reported hip function and quality of life. In this study, THA delivered a long-lasting solution to hip pain with survival similar to that seen in patients undergoing THA in the fourth and fifth decades of life. Socioeconomic benefits of THA need further investigation to establish treatment guidelines for children suffering with hip pain.
DYSPLASTIC HIPS THAT ARE TOO LATE FOR PERIACETABULAR OSTEOTOMY ARE NOT TOO EARLY FOR TOTAL HIP ARTHROPLASTY
Authors: Treu E. A. , Sato E. H. , Omotowa O. M. , Heaton T. B. , Erickson J. A. , Blackburn B. E. , Anderson L. A. , Peters C. L.
Published: August 2024

Total hip arthroplasty (THA) is often performed in symptomatic patients with developmental dysplasia of the hip (DDH) who do not qualify for periacetabular osteotomy (PAO). The impact of osteoarthritis (OA) severity on postoperative outcomes in DDH patients who undergo THA is not well described. We hypothesized that DDH patients who undergo THA with mild OA have slower initial recovery postoperatively, but similar one-year patient reported outcome measures (PROMs) when compared to DDH patients with severe OA.

We performed a retrospective review at a single academic institution over a six-year period of patients with DDH who underwent primary THA and compared them to patients without DDH who underwent THA. Within the DDH cohort, we compared PROMs stratified by DDH severity and OA severity. Diagnosis of DDH was verified using radiographic lateral center edge angle (LCEA). Minimum one-year follow-up was required. PROMs were collected through one-year postoperatively. Logistic and linear regression models were used adjusting for age, sex, body mass index, and Charlson Comorbidity Index.

263 patients with DDH were compared to 1,225 THA patients without DDH. No significant differences were found in postoperative PROMs or revision rates (p=0.49). When stratified by DDH severity, patients with LCEA<10° had worse preoperative pain (p=0.01), mental health (p<0.01) and physical function (p=0.03) scores but no significant difference in postoperative PROMs. Within the DDH group, when stratified by OA severity, patients with Grade 3 Tonnis score had worse preoperative pain (p=0.04) but no significant difference in postoperative PROMs. Recovery curves in DDH patients based upon severity of DDH and OA were not significantly different at 2-weeks, 6-weeks and 1-year.

DDH patients who have mild OA have similar recovery curves compared to those with severe OA. THA is reasonable in symptomatic DDH patients who have mild arthritis and do not qualify for PAO.
TROCHANTERIC OSTEOTOMY AND TRANSFER DURING TOTAL HIP ARTHROPLASTY IN PATIENTS WITH DISLOCATED DYSPLASTIC HIPS: UNION RATE USING MONOFILAMENT TRANSVERSE WIRE CERCLAGE
Authors: Kalhor M.
Published: August 2024

Securing the osteotomized greater trochanter (GT) during total hip arthroplasty (THA) for dislocated dysplastic hips (DDH) poses a significant challenge. This study evaluates the union rate and effectiveness of a 2-strand transverse wiring technique utilizing the lesser trochanter for wire anchorage and tensioning.

A digastric anterior slide trochanteric osteotomy was performed in 106 patients (118 hips) undergoing THA for DDH. Following uncemented stem insertion, the GT was transferred and fixed to the lateral cortex of the proximal femur using monofilament stainless steel wires. In 72 out of 106 patients (80 hips), the GT was fixed with 2 transverse wire cerclages threaded through 2 drill holes in the base of the lesser trochanter, spaced vertically 5–10 millimeters apart. The wires were wrapped transversely over the GT and tightened, avoiding contact with its tendinous attachments. Patients were regularly monitored, and GT union was assessed clinically and radiographically.

Patient ages ranged from 20 to 57 years (mean 35.5), with a follow-up period ranging from 1.5 to 12 years (mean 6.2). The mean union time was 3.3 months (range 2–7). Among all hips, two developed stable nonunion and single wire breakage, but no fragment displacement (2.5%). Two hips exhibited delayed union, eventually healing at 6 and 7 months after surgery.

Reattachment of the greater trochanter utilizing a 2-strand transverse wire cerclage anchored at the base of the lesser trochanter demonstrated a high rate of union (97.5%) following THA in dislocated DDH cases.
TOTAL HIP ARTHROPLASTY IN PATIENTS WITH ANGULAR PROXIMAL FEMORAL DEFORMITIES
Authors: Dagneaux L. , Abdel M. P. , Sierra R. J. , Lewallen D. G. , Trousdale R. T. , Berry D. J.
Published: August 2024

Angular proximal femoral deformities increase the technical complexity of primary total hip arthroplasties (THAs). The goals were to determine the long-term implant survivorship, risk factors, complications, and clinical outcomes of contemporary primary THAs in this difficult cohort.

Our institutional total joint registry was used to identify 119 primary THAs performed in 109 patients with an angular proximal femoral deformity between 1997 and 2017. The deformity was related to previous femoral osteotomy in 85%, and developmental or metabolic disorders in 15%. 53% had a predominantly varus angular deformity. The mean age was 44 years, mean BMI was 29 kg/m2, and 59% were female. An uncemented metaphyseal fixation stem was used in 30%, an uncemented diaphyseal fixation stem in 28%, an uncemented modular body stem with metaphyseal fixation sleeve in 24%, and a cemented stem in 18%. Simultaneous corrective femoral osteotomy was performed in 18%. Kaplan-Meier survivorships and Harris hip scores were reported. Mean follow-up was 8 years.

The 10-year survivorships free of femoral loosening, aseptic femoral revision, any revision, and any reoperation were 95%, 93%, 90% and 88%, respectively. Revisions occurred in 13 hips for: aseptic femoral component loosening (3), stem fracture (2), dislocation (2), aseptic acetabular loosening (2), polyethylene liner exchange (2), and infection (2). Preoperative varus angular deformities were associated with a higher risk of any revision (HR 10, p=0.03), and simultaneous osteotomies with a higher risk of any reoperation (HR 3.6, p=0.02). Mean Harris hip scores improved from 52 preoperatively to 82 at 10 years (p<0.001).

In the largest series to date of primary THAs in patients with angular proximal femoral deformities, we found a good 10-year survivorship free from any revision. Varus angular deformities, particularly those treated with a simultaneous osteotomy due to the magnitude or location of the deformity, had a higher reoperation rate.

Keywords: Proximal femoral deformity; dysplasia; femoral osteotomy; survivorship; revision

Level of evidence: Level III, comparative retrospective cohort
ANATOMICAL STUDY OF PERCUTANEOUS TENOTOMY OF THE ILIOPSOAS TENDON GUIDED BY ULTRASOUND IN CADAVERS: A VIABLE TECHNIQUE?
Authors: Polesello G. C. , Ricioli W. , Gonçalves C. I.
Published: August 2024

The objective of this study is to evaluate the effectiveness and safety of percutaneous tenotomy of the iliopsoas tendon with the aid of ultrasound in cadavers.

An anatomical and descriptive study of the technique of percutaneous tenotomy of the iliopsoas tendon guided by ultrasound and to share our experience in performing it and its reproducibility in clinical practice.

Out of 20 tenotomies, 17 were total, performed at the level of the superior border of the acetabulum. Three tenotomies were partial, with more than 75% of the tendon being sectioned in all three. During one of the tenotomies, there was a partial injury to the femoral nerve. Measurements were made of the distance between the site where the blade was inserted and the femoral nerve, a noble structure that would be at greater risk during the procedure, with an average distance of 8.4 millimeters.

Ultrasound-guided iliopsoas tendon release procedures have the ability to be performed in a cadaveric model, consistently achieving complete tendon release, except in cases of obesity, with minimal repercussions on adjacent structures, and require approximately 4 minutes to complete.
ABDUCTOR RECONSTRUCTION WITH VASTUS LATERALIS TO GLUTEUS MEDIUS TRANSFER
Authors: Caplash G. , Caplash Y. , Copson D. , Thewlis D. , Ehrlich A. , Solomon L. B. , Ramasamy B.
Published: August 2024

Few surgical techniques to reconstruct the abductor mechanism of the hip have been reported, with outcomes reported only from case reports and small case series from the centres that described the techniques. As in many of our revision THA patients the gluteus maximus was affected by previous repeat posterior approaches, we opted to reconstruct the abductor mechanism using a vastus lateralis to gluteus medius transfer.

We report the results of such reconstructions in seven patients, mean age 66 (range, 53–77), five females, presenting with severe abductor deficiency (MRC grade 1–2). Five patients had previous revision THA, two with a proximal femoral replacement, one patient had a primary THA after a failed malunited trochanteric fracture, and one patient had a native hip with idiopathic fatty infiltration of glutei of >90%. All patients had instrumented gait analysis, and surface electromyography (EMG) of the glutei, TFL, and vastus muscles simultaneously before surgery and at each post-op follow-up. Postoperatively, patients were allowed to weight bear as tolerated and were requested to wear an abduction brace for the first six weeks after surgery to protect the transfer.

All patients improved after surgery and reached an abductor power of 3 or more. All patients walked without support six months after surgery and were satisfied with the result. Abductor function continued to improve beyond one year of follow-up, and some patients reached an abductor power of 5. EMG demonstrated that the transferred vastus lateralis started firing synchronously with gluteus medius after three months post-surgery, suggesting adaptation to its new function. No knee extension weakness was recorded. One patient complained of lateral thigh numbness and was dissatisfied with the cosmetic look of her thigh after surgery.

Our preliminary results are encouraging and comparable with those achieved by the originators of the technique.
UNDERSTANDING THE MULTI-SYSTEM MANIFESTATIONS OF HYPERMOBILITY IN YOUR PATIENTS
Authors: Papatheofanis C. , Healey R. , Muldoon M. , Barlow B. , Santore R.
Published: August 2024

Hypermobility Spectrum Disorder (HSD or hEDS) is attributed to a collagen abnormality associated with excessive joint flexibility. Approximately 90% of females with hip dysplasia have hypermobility. Manifestations of hypermobility in various body systems are unique to every patient, affecting different tissues of the body with varying degrees of severity. Our purposes were to identify the manifestations of hypermobility across multiple body systems and to study the recognition of hypermobility in the medical literature of multiple specialties over multiple decades.

A literature search of the major medical disciplines for key words associated with HSD was performed. These specialties included gastroenterology, gynecology, neurology, psychiatry, oral-maxillofacial surgery, cardiology, and orthopaedic surgery. A specialty-specific impact factor (IF) score was calculated as the percentage of research articles that referenced hypermobility as a comorbidity over all articles within that specialty. Statistical differences were identified using single factor ANOVA with significance determined at p<0.05. We reviewed many published, specialty-specific manifestations of hypermobility, and describe them.

All six non-orthopaedic specialties demonstrated a continually increasing relative IF ratio throughout the study period with a peak impact average of 0.22 (p<0.05 compared with other time ranges). There was a 93.3% overall increase in IF scores from the 1992–1998 period to the most recent period examined (p<0.05).

Hypermobility is increasingly recognized as a significant health issue in multiple disciplines. Since dysplasia is associated with approximately 40% of all primary total hip arthroplasty cases, understanding the multi-system manifestations, and broad impact of hypermobility on patients, is relevant for every hip surgeon. We are expanding our research into other medical disciplines, including urology, ophthalmology, dermatology, clinical psychology, and others.
LONG-TERM SURVIVORSHIP OF METAL-ON-METAL HIP RESURFACING ARTHROPLASTY: COMPARATIVE COHORT STUDY AT 15 YEARS
Authors: Meek D.
Published: August 2024

In 1997 the Birmingham Hip Resurfacing was introduced to address the needs of young active patients. Alternative designs were introduced to try and improve wear performance. The aim of this study was a comparative cohort study of two types of metal-on-metal bearing to determine the mechanism of failure at 15 years.

The study reviewed 91 Brimingham Hip Resurfacings (BHR) (Smith and Nephew) and 715 DUROM hip resurfacing (Zimmer) procedures in prior to 2009. Failure was defined as revision of either component for any reason. Kaplan-Meyer survivorship analysis performed. Routine follow-up with serum metal ion levels and radiographs.

Mean follow-up was 17.9 years (range 15.2 – 25.1). The mean age at operation was 51.6 years (SD 8.6, range 20.7 to 70.2), including 299 women (37.1%). The Birmingham resurfacing demonstrated 92.3% survivorship at 15 years (SE 2.8, 95% CI 3.9 – 7.8) and 90.0% at latest follow-up (SE 3.5, 95% CI 4.9 to 9.4). By comparison, the DUROM survivorship at 15 years was 89.1% at 15 years (SE 1.2, 95% CI 2.0 to 2.5) and 87.4% (SE 1.3, 95% CI 2.5 to 2.3) at latest follow-up. There was no statistically significant difference in survivorship between groups (p= 0.32). Survival in male patients was 92.7% compared to 80.0% in females. The reported failures occurred from Adverse Reaction to Metal Debris (32 patients), periprosthetic femoral neck fracture (6) and aseptic loosening (41), PJI (12) and undiagnosed pain (6). The mean cobalt and chromium levels at last follow-up were 33.4 nmol/L and 36.5 nmol/L respectively.

This study demonstrates two differently designed metal-on-metal hip resurfacing provided a durable alternative to total hip replacement, particularly in younger male patients with osteoarthritis. Differences in design did determine the reason for revision with acetabular fixation being one of the principal failure mechanisms for the DUROM compared to elevated ion levels.
RECTANGULAR TAPER STEM DESIGNS ARE ASSOCIATED WITH A HIGHER RISK FOR PERIPROSTHETIC FEMORAL FRACTURES AFTER CEMENTLESS TOTAL HIP ARTHROPLASTY
Authors: Park C.-W. , Lim S.-J. , Park Y.-S.
Published: August 2024

Periprosthetic femoral fractures (PFFs) remain a major concern following cementless total hip arthroplasty (THA). This study aimed to evaluate the association between different types of cementless tapered stems and the risk of postoperative PFF.

A retrospective review of primary THAs performed at a single center from January 2011 to December 2018 included 3,315 hips (2,326 patients). Cementless stems were classified according to their design geometry using the system proposed by Radaelli et al. The incidence of PFF was compared between flat taper porous-coated stems (type A), rectangular taper grit-blasted stems (type B1), and quadrangular taper hydroxyapatite-coated stems (type B2). Multivariate regression analyses were performed to identify independent factors related to PFF. The mean follow-up duration was 61 months (range, 12‒139 months).

Overall, 45 (1.4%) postoperative PFFs occurred. The incidence of PFF was significantly higher in type B1 stems than in type A and type B2 stems (1.8 vs. 0.7 vs. 0.7%; P=0.022). Additionally, more surgical treatments (1.7 vs. 0.5 vs. 0.7%; P=0.013) and femoral revisions (1.2 vs. 0.2 vs. 0%; P=0.004) were required for PFF in type B1 stems. After controlling for confounding variables, older age (P<0.001), diagnosis of hip fracture (P<0.001), and use of type B1 stems (P=0.001) were significant factors associated with PFF.

Type B1 rectangular taper stems were found to have higher risks for postoperative PFF and PFF requiring surgical management than type A and type B2 stems in THA. Femoral stem geometry should be considered when planning for cementless THA in elderly patients with compromised bone quality.
RISK OF PERIPROSTHETIC FRACTURE AFTER PRIMARY TOTAL HIP ARTHROPLASTY USING A COLLARED CEMENTLESS (CC) OR TAPER-SLIP CEMENTED STEM (PTS)
Authors: Beverland D. , Wong M. Lynch , Robinson M. , Cassidy R. , Lamb J. , Diamond O.
Published: August 2024

A: - determine the incidence of intraoperative periprosthetic femoral fracture (PFF)

B: - determine the incidence of, and the reoperation rate for postoperative PFF

When using either CC or PTS femoral components.

Retrospective review of a consecutive series of 11,018 THAs over a ten-year period. All PFFs were identified using regional radiograph archiving and electronic care systems.

Of the 11,018 THAs 4,952 were CC and 6,066 were PTS. Between groups, age, sex, and BMI did not differ.

A: - 55 (0.5%) had an intraoperative PFF. 44 CC and 11 PTS (p<0.001). 3 patients in each group had a femoral shaft fracture, remaining fractures were either the calcar (20 CC and 2 group) or the greater trochanter (11 CC and 6 PTS).

B: - 91(0.8%) sustained a postoperative PFF. Of those 15 were managed conservatively, 15 were revised and 61 (80.3%) had an ORIF. The CC group had both a lower overall rate of postoperative PFFs (0.7% (36/4,952) vs 0.9% (55/6,066); p = 0.341), and a lower rate of return to theatre (0.4% (22/4,952) vs 0.9% (54/6,066); p = 0.005). 1.3% of male PTS (36/2,674) had a reoperation compared to 0.3% of male CC (7/2,121) (p<0.001).

With regard to stem fracture there were none in the Corail group and 5 in the Exeter group. Of these 2 were sub trunnion and 3 were basal neck.

A: - There were significantly more intraoperative PFFs with CC 44 (0.8%) than PTS 11 (0.2%). However, the majority of fractures were either of the calcar or greater trochanter with no impact on early recovery or one year Oxford scores.

B: - Male PTS were five times more likely to have a reoperation for postoperative PFF. Females had the same incidence of reoperation with either component type.

There were 5 stem fractures in the Exeter group and none in the Corail.

These results represent robust estimates, which are likely to be more accurate than revision only studies typically generated from registry data.
RECONSTRUCTION OF PAPROSKY TYPE III ACETABULAR BONE DEFECTS IN REVISION HIP ARTHROPLASTY USING A COMBINATION OF CAGE AND MORSELIZED ALLOGRAFTS
Authors: Zhou Z.
Published: August 2024

The management of severe acetabular bone defects poses a complex challenge in revision hip arthroplasty. Although biological fixation materials are currently dominant, cage has played an important role in complex acetabular revision in the past decades, especially when a biological prosthesis is not available. The purpose of this study is to report the long-term clinical and radiographic results of Paprosky type Ⅲ acetabular bone defects revised with cage and morselized allografts.

We retrospectively analyzed 45 patients who underwent revision hip arthroplasty with cage and morselized allografts between January 2007 and January 2019. Forty-three patients were followed up. There were 19 Paprosky type IIIA bone defect patients and 24 Paprosky type IIIB bone defect patients and 7 patients of the 24 were also with pelvic discontinuity. Clinical assessment included Harris Hip Score (HHS) and Short Form-12 (SF-12). Radiographic assessment included cage stability, allografts incorporation, and center of rotation.

All patients were followed up with a mean follow-up of 10.6 years, HHS and SF-12 improved significantly at last follow-up in comparison to the preoperative. There were 2 re-revisions, one at 5 years after surgery, another at 13.6 years after surgery. Two patients had nonprogressive radiolucency in zone III and the junction of zone II and zone III at the bone implant interface. Allografts of 40 (93%) cases incorporated fully.

The combination of cage and morselized allograft is an alternative option for acetabular revision with Paprosky type III bone defects with satisfactory long-term follow-up results.
BEARING SELECTION IN REVISION TOTAL HIP ARTHROPLASTY: RATIONALE, ALGORITHM, AND OUTCOME
Authors: Jones S. A. , Davies O.
Published: August 2024

Dislocation following revision THA remains a leading cause of failure. Integrity of the abductor muscles is a major contributor to stability. Large diameter heads (LDH), Dual Mobility (DM) and Constrained Acetabular Liners (CAL) are enhanced stability options but the indication for these choices remains unclear.

We assessed an algorithm based on Gluteus Medius (GM) deficiency to determine bearing selection. Default choice with no GM damage was a LDH. GM deficiency with posterior muscle intact received DM and CAL for GM complete deficiency with loss of posterior muscle.

Consecutive revision THA series followed to determine dislocation, all-cause re-revision and Oxford Hip Score (OHS).

311 revision THA with mean age 70 years (32–95). At a mean follow-up of 4.8 years overall dislocation rate 4.1% (95%CI 2.4–7.0) and survivorship free of re-revision 94.2% (95%CI 96.3–91.0). Outcomes:

Group 1 - LDH (36 & 40mm) n=164 / 4 dislocations / 7 re-revisions

Group 2 - DM n=73 / 3 dislocations / 4 re-revisions

Group 3 - CAL n=58 / 5 dislocations / 7 re-revisions

Group 4 - Other (28 & 32mm) n=16 / 1 dislocation / no re-revisions

Mean pre-op OHS: 19.6 (2–47) and mean post-op OHS: 33.9 (4–48). Kaplan-Meier analysis at 60 months dislocation-free survival was 96.1% (95% CI: 93.0–97.8). There was no difference between survival distributions comparing bearing choice (p=0.46).

Decision making tools to guide selection are limited and in addition soft tissue deficiency has been poorly defined. The posterior vertical fibres of GM have the greatest lateral stabiliser effect on the hip. The algorithm we have used clearly defined indication & implant selection. We believe our outcomes support the use of an enhanced stability bearing selection algorithm.
DECODING THE TIMELINE: PREDICTING RETURN TO SPORT AFTER PERIACETABULAR OSTEOTOMY WITH PRECISION MODELLING
Authors: Nonnenmacher L. , Fischer M. , Kaderali L. , Wassilew G. I.
Published: August 2024

Periacetabular Osteotomy (PAO) has become the most important surgical procedure for patients with hip dysplasia, offering significant pain relief and improved joint function. This study focuses on recovery after PAO, specifically the return to sports (RTS) timeline, with the objective of identifying preoperative predictors to optimize patient outcomes.

Our prospective, monocentric study from 2019 to 2023 included 698 hips from 606 patients undergoing PAO. Comprehensive preoperative data were collected, including demographic information, clinical assessments (Modified Harris Hip Score (mHHS), International Hip Outcome Tool-12 (iHot-12), Hip Disability and Osteoarthritis Outcome Score (HOOS), UCLA Activity Score) and psychological evaluations (Brief Symptom Inventory (BSI) and SF-36 Health Survey). Advanced logistic regression and machine learning techniques (R Core Team. (2016)) were employed to develop a predictive model.

Multivariate regression analysis revealed that several preoperative factors significantly influenced the RTS timeline. These included gender, invasiveness of the surgical approach, preoperative UCLA Score, preoperative sports activity level, mHHS, and various HOOS subscales (Sport/Recreation, Symptoms, Pain) as well as psychological factors (BSI and SF-36). The subsequent model, using a decision tree approach, showed that the combination of a UCLA score greater than 3 (p<0.001), non-female gender (p=0.003), preoperative sports frequency not less than twice per week (p<0.001), participation in high-impact sports preoperatively (p=0.008), and a BSI anxiety score less than 2 (p<0.001) had the highest likelihood of early RTS with a probability of 71.4% at three months.

Using a decision tree approach, this model provides a nuanced prediction of RTS after PAO, highlighting the synergy of physical, psychological, and lifestyle influences. By quantifying the impact of these variables, it provides clinicians with a valuable tool for predicting individual patient recovery trajectories, aiding in tailored rehabilitation planning and predicting postoperative satisfaction.
EFFECT OF FEMORAL ROTATION ON DISLOCATION AFTER REVISION TOTAL HIP ARTHROPLASTY
Authors: Hieda Y. , Choe H. , Ike H. , Abe K. , Shimoda M. , Kumagai K. , Kobayashi N. , Inaba Y.
Published: August 2024

Dislocation is a serious complication to be avoided in total hip arthroplasty (THA) and its incidence risk increases in revision surgery. Combined anteversion (CA) of the cup and stem is a concept for appropriate implant positioning; however, the effect of functional changes in femoral rotation has not been well investigated. The aim of this study was to investigate whether functional CA, considering femoral rotation, is associated with dislocation in patients undergoing revision THA.

Seventy-three patients who underwent revision THA and had at least one year of follow-up with pre- and postoperative supine CT imaging were included. Cup and stem were placed with a target combined angle of 37.3° using Widmer's formula. Anatomical and functional CA was calculated postoperatively using the following formula: Anatomical CA: cup anteversion + 0.7 × anatomical stem anteversion; Functional CA: cup anteversion + 0.7 × (anatomical stem anteversion + femoral rotation). Patient demographics, cup and stem angles, CA and their relationship to dislocation were statistically evaluated.

Dislocation was observed in 12 patients. In these dislocated cases, there were no significant differences in cup angle, stem angle and anatomical CA compared to non-dislocated cases. However, dislocated cases showed significantly higher values of functional CA [52.7 ± 17.5° (range, 5.9–69.3) vs. 36.0 ± 12.5° (range, 8.6–68.8), p=0.009] and significant deviation from identical CA [17.3 ± 9.6° (range, 2.8–32) vs. 7.5 ± 7.1° (range, 0.1–28.7), p=0.010].

Functional CA considering femoral rotation was associated with dislocation in revision THA patients. This finding suggests that consideration of femoral rotation may be necessary for implant positioning in revision THA.
COMPARISON OF THE CT-BASED MICROMOTION ANALYSIS METHOD VERSUS MARKER-BASED RADIOSTEREOMETRIC ANALYSIS IN MEASURING FEMORAL STEM MIGRATION
Authors: Angelomenos V. , Shareghi B. , Itayem R. , Mohaddes M.
Published: August 2024

Early micromotion of hip implants measured with radiostereometric analysis (RSA) is a predictor for late aseptic loosening. Computed Tomography Radiostereometric Analysis (CT-RSA) can be used to determine implant micro-movements using low-dose CT scans. CT-RSA enables a non-invasive measurement of implants. We evaluated the precision of CT-RSA in measuring early stem migration. Standard marker-based RSA was used as reference. We hypothesised that CT-RSA can be used as an alternative to RSA in assessing implant micromotions.

We included 31 patients undergoing Total Hip Arthroplasty (THA). Distal femoral stem migration at 1 year was measured with both RSA and CT-RSA. Comparison of the two methods was performed with paired-analysis and Bland-Altman plots. Furthermore, the inter- and intraobserver reliability of the CT-RSA method was evaluated.

No statistical difference was found between RSA and CTMA measurements. The Bland-Altman plots showed good agreement between marker-based RSA and CT-RSA. The intra- and interobserver reliability of the CT-RSA method was found to be excellent (≥0.992).

CT-RSA is comparable to marker-based RSA in measuring distal femoral stem migration. CTMA can be used as an alternative method to detect early implant migration.