VC-dimension of short Presburger formulas

We study VC-dimension of short formulas in Presburger Arithmetic, defined to have a bounded number of variables, quantifiers and atoms. We give both lower and upper bounds, which are tight up to a polynomial factor in the bit length of the formula

Defining an International Standard Set of Outcome Measures for Patients With Hip or Knee Osteoarthritis: Consensus of the International Consortium for Health Outcomes Measurement Hip and Knee Osteoarthritis Working Group

OBJECTIVE: To define a minimum Standard Set of outcome measures and case-mix factors for monitoring, comparing, and improving health care for patients with clinically diagnosed hip or knee osteoarthritis (OA), with a focus on defining the outcomes that matter most to patients. METHODS: An international working group of patients, arthroplasty register experts, orthopedic surgeons, primary care physicians, rheumatologists, and physiotherapists representing 10 countries was assembled to review existing literature and practices for assessing outcomes of pharmacologic and nonpharmacologic OA therapies, including surgery. A series of 8 teleconferences, incorporating a modified Delphi process, were held to reach consensus. RESULTS: The working group reached consensus on a concise set of outcome measures to evaluate patients\u27 joint pain, physical functioning, health-related quality of life, work status, mortality, reoperations, readmissions, and overall satisfaction with treatment result. To support analysis of these outcome measures, pertinent baseline characteristics and risk factor metrics were defined. Annual outcome measurement is recommended for all patients. CONCLUSION: We have defined a Standard Set of outcome measures for monitoring the care of people with clinically diagnosed hip or knee OA that is appropriate for use across all treatment and care settings. We believe this Standard Set provides meaningful, comparable, and easy to interpret measures ready to implement in clinics and/or registries globally. We view this set as an initial step that, when combined with cost data, will facilitate value-based health care improvements in the treatment of hip and knee OA

Systematic review of injuries and chronic musculoskeletal pain among high-speed boat operators

Introduction: High-speed boat operators constitute a population at risk of work-related injuries and disabilities. This review aimed to summarize the available knowledge on workplace-related injuries and chronic musculoskeletal pain among high-speed boat operators. Materials and Methods: In this systematic review, we searched Medline, Embase, Scopus, and the Cochrane Library Database for studies, published AQ9 from 1980 to 2022, on occupational health and hazards onboard high-speed boats. Studies and reports were eligible for inclusion if they evaluated, compared, used, or described harms associated with impact exposure onboard high-speed boats. Studies on recreational injuries and operators of unplanned boats were excluded. The primary outcome of interest was the incidence of acute injuries. The secondary outcome measures comprised the presence of chronic musculoskeletal disorders, pain medication use, and days off work. Results: Of the 163 search results, 5 (2 prospective longitudinal and 3 cross-sectional cohort studies) were included in this systematic review. A total of 804 cases with 3,312 injuries sustained during 3,467 person-years onboard high-speed boats were included in the synthesis of the results. The pooled incidence rate was 1.0 per person-year. The most common injuries were related to the lower back (26%), followed by neck (16%) and head (12%) injuries. The pooled prevalence of chronic pain was 74% (95% CI: 73–75%) and 60% (95% CI: 59–62%) of the cohort consumed analgesics. Conclusions: Despite very limited data, this review found evidence that high-speed boat operators have a higher rate of injuries and a higher prevalence of chronic pain than other naval service operators and the general workforce. Given the low certainty of these findings, further prospective research is required to verify the injury incidence and chronic pain prevalence among high-speed boat operators. Review registration: PROSPERO: CRD4202235892

Genomics of Staphylococcus aureus and Staphylococcus epidermidis from periprosthetic joint infections and correlation to clinical outcome

The approach of sequencing or genotyping to characterize the pathogenic potential of staphylococci from orthopedic device-related infection (ODRI) has been applied in recent studies. These studies described the genomic carriage of virulence in clinical strains and compared it with those in commensal strains. Only a few studies have directly correlated genomic profiles to patient outcome and phenotypic virulence properties in periprosthetic joint infections (PJIs). We investigated the association between genomic variations and virulence-associated phenotypes (biofilm-forming ability and antimicrobial resistance) in 111 staphylococcal strains isolated from patients with PJI and the infection outcome (resolved/unresolved). The presence of a strong biofilm phenotype in Staphylococcus aureus and an antibiotic-resistant phenotype in Staphylococcus epidermidis were both associated with treatment failure of PJI. In S. epidermidis, multidrug resistance (MDR) and resistance to rifampicin were associated with unresolved infection. Sequence type 45 (ST45) and ST2 were particularly enriched in S. aureus and S. epidermidis, respectively. S. epidermidis ST2 caused the majority of relapses and was associated with MDR and strong biofilm production, whereas ST215 correlated with MDR and non/weak biofilm production. S. aureus agr II correlated with resolved infection, while S. epidermidis agr I was associated with strong biofilm production and agr III with non/weak production. Collectively, our results highlight the importance of careful genomic and phenotypic characterization to anticipate the probability of the strain causing treatment failure in PJI. Due to the high rate of resistant S. epidermidis strains identified, this study provides evidence that the current recommended treatment of rifampicin and a fluoroquinolone should not be administered without knowledge of the resistance pattern

Worse health-related quality of life and hip function in female patients with elevated chromium levels: A prospective study of 659 patients with a recalled THR metal-on-metal implant

Background and purpose Blood metal ion levels can be an indicator for detecting implant failure in metal-on-metal (MoM) hip arthroplasties. Little is known about the effect of bilateral MoM implants on metal ion levels and patient-reported outcomes. We compared unilateral patients and bilateral patients with either an ASR hip resurfacing (HR) or an ASR XL total hip replacement (THR) and investigated whether cobalt or chromium was associated with a broad spectrum of patient outcomes. Patients and methods From a registry of 1,328 patients enrolled in a multicenter prospective follow-up of the ASR Hip System, which was recalled in 2010, we analyzed data from 659 patients (311 HR, 348 THR) who met our inclusion criteria. Cobalt and chromium blood metal ion levels were measured and a 21-item patient-reported outcome measures (PROMs) questionnaire was used mean 6 years after index surgery. Results: Using a minimal threshold of ≥7 ppb, elevated chromium ion levels were found to be associated with worse health-related quality of life (HRQoL) (p < 0.05) and hip function (p < 0.05) in women. These associations were not observed in men. Patients with a unilateral ASR HR had lower levels of cobalt ions than bilateral ASR HR patients (p < 0.001) but similar levels of chromium ions (p = 0.09). Unilateral ASR XL THR patients had lower chromium and cobalt ion levels (p < 0.005) than bilateral ASR XL THR patients. Interpretation Chromium ion levels of ≥7 ppb were associated with reduced functional outcomes in female MoM patients

Is Preoperative Patient-Reported Health Status Associated with Mortality after Total Hip Replacement?

The influence of comorbidities and worse physical status on mortality following total hip replacement (THR) leads to the idea that patient-reported health status may also be a predictor of mortality. 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. For these analyses, we used register data on 42,862 THR patients with primary hip osteoarthritis operated between 2008 and 2012. The relative survival ratio was calculated by dividing the observed survival in the patient group by age- and sex-adjusted expected survival of the general population. Pre-operative responses to the five EQ-5D-3L (EuroQol Group) dimensions along with age, sex, education status, year of surgery, and hospital type were used as independent variables. Results shown that, as a group, THR patients had a better survival than the general population. Broken down by the five EQ-5D-3L dimensions we observed differentiated survival patters. For all dimensions, those reporting extreme problems had higher mortality than those reporting moderate or no problems. In conclusion, worse health status according to the EQ-5-3L before THR is associated with higher mortality up to five years after surgery. EQ-5D-3L responses may be useful in a multifactorial individualized risk assessment before THR.This article is freely available via Open Access. Click on the Additional Link above to access the full-text via the publisher's site

Total hip arthroplasties in the Dutch Arthroplasty Register (LROI) and the Nordic Arthroplasty Register Association (NARA): comparison of patient and procedure characteristics in 475,685 cases

Background and purpose — Collaborations between arthroplasty registries are important in order to create the possibility of detecting inferior implants early and improve our understanding of differences between nations in terms of indications and outcomes. In this registry study we compared patient and procedure characteristics, and revision rates in the Nordic Arthroplasty Register Association (NARA) database and the Dutch Arthroplasty Register (LROI). Patients and methods — All total hip arthroplasties (THAs) performed in 2010–2016 were included from the LROI (n = 184,862) and the NARA database (n = 290,823), which contains data from Denmark, Norway, Sweden, and Finland. Descriptive statistics and Kaplan–Meier survival analyses based on all reasons for revision and stratified by fixation were performed and compared between countries. Results — In the Netherlands, the proportion of patients aged < 55 years (9%) and male patients (34%) was lower than in Nordic countries (< 55 years 11–13%; males 35–43%); the proportion of osteoarthritis (OA) (87%) was higher compared with Sweden (81%), Norway (77%), and Denmark (81%) but comparable to Finland (86%). Uncemented fixation was used in 62% of patients in the Netherlands, in 70% of patients in Denmark and Finland, and in 28% and 19% in Norway and Sweden, respectively. The 5-year revision rate for THAs for OA was lower in Sweden (2.3%, 95% CI 2.1–2.5) than in the Netherlands (3.0%, CI 2.9–3.1), Norway (3.8%, CI 3.6–4.0), Denmark (4.6%, CI 4.4–4.8), and Finland (4.4%, CI 4.3–4.5). Revision rates in Denmark, Norway, and Finland were higher for all fixation groups. Interpretation — Patient and THA procedure characteristics as well as revision rates evinced some differences between the Netherlands and the Nordic countries. The Netherlands compared best with Denmark in terms of patient and procedure characteristics, but resembled Sweden more in terms of short-term revision risk. Combining data from registries like LROI and the NARA collaboration is feasible and might possibly enable tracking of potential outlier implants.publishedVersio

Incidence and correlates of delirium in a West African mental health clinic

Objective: &lt;br/&gt; &lt;br/&gt; To determine the incidence of delirium in those patients presenting to a psychiatric clinic in Nigeria and to examine if any demographic or clinical variables were correlated with this diagnosis. &lt;br/&gt; &lt;br/&gt; Method &lt;br/&gt; &lt;br/&gt; A prospective survey design; 264 consecutive new referrals to a psychiatric clinic in Nigeria were assessed for the presence of delirium using a standardised diagnostic scale. Data was analysed for normality and appropriate statistical test employed to examine the relationships between the presence of delirium and demographic and clinical variables. &lt;br/&gt; &lt;br/&gt; Results &lt;br/&gt; &lt;br/&gt; Of individuals presenting to the mental health clinics, 18.2% had delirium. No demographic variable was significant regarding the presence or absence of delirium. With regard to clinical variables duration of current symptoms, referral source and the presence of comorbid physical illness were significantly associated with the presence of delirium. Most delirium was due to infections. Nearly all patients with delirium were prescribed psychotropic medication (95.2%), and most attributed their symptoms to a spiritual cause.Conclusion(s) Delirium presents more commonly to psychiatry services in the less developed world compared to the West. Development efforts should focus on recognition and management of delirium to improve outcomes and maximise resource

Does cup position differ between trabecular metal and titanium cups? : A radiographic propensity score matched study of 300 hips

Background and purpose - The use of trabecular metal cups in primary total hip arthroplasty (THA) is increasing, despite the survival of Continuum cups being slightly inferior compared with other uncemented cups in registries. This difference is mainly explained by a higher rate of dislocation revisions. Cup malpositioning is a risk factor for dislocation and, being made of a highly porous material, Continuum cups might be more difficult to position. We evaluated whether Continuum cups had worse cup positioning compared with other uncemented cups.Patients and methods - Based on power calculation, 150 Continuum cups from 1 center were propensity score matched with 150 other uncemented cups from 4 centers. All patients had an uncemented stem, femoral head size of 32 mm or 36 mm, and BMI between 19 and 35. All operations were done for primary osteoarthrosis through a posterior approach. Patients were matched using age, sex, and BMI. Cup positioning was measured from anteroposterior pelvic radiograph using the Martell Hip Analysis Suite software.Results - There was no clinically relevant difference in mean inclination angle between the study group and the control group (43° [95% CI 41-44] and 43° [CI 42-45], respectively). The study group had a larger mean anteversion angle compared with the control group, 19° (CI 18-20) and 17° (CI 15-18) respectively.Interpretation - Continuum cups had a greater anteversion compared with the other uncemented cups. However, the median anteversion was acceptable in both groups and this difference does not explain the larger dislocation rate in the Continuum cups observed in earlier studies.publishedVersionPeer reviewe

Increased Long-Term Cardiovascular Risk After Total Hip Arthroplasty: A Nationwide Cohort Study

Abstract Total hip arthroplasty is a common and important treatment for osteoarthritis patients. Long-term cardiovascular effects elicited by osteoarthritis or the implant itself remain unknown. The purpose of the present study was to determine if there is an increased risk of late cardiovascular mortality and morbidity after total hip arthroplasty surgery. A nationwide matched cohort study with data on 91,527 osteoarthritis patients operated on, obtained from the Swedish Hip Arthroplasty Register. A control cohort (n = 270,688) from the general Swedish population was matched 1:3 to each case by sex, age, and residence. Mean follow-up time was 10 years (range, 7–21). The exposure was presence of a hip replacement for more than 5 years. The primary outcome was cardiovascular mortality after 5 years. Secondary outcomes were total mortality and re-admissions due to cardiovascular events. During the first 5 to 9 years, the arthroplasty cohort had a lower cardiovascular mortality risk compared with the control cohort. However, the risk in the arthroplasty cohort increased over time and was higher than in controls after 8.8 years (95% confidence interval [CI] 7.0–10.5). Between 9 and 13 years postoperatively, the hazard ratio was 1.11 (95% CI 1.05–1.17). Arthroplasty patients were also more frequently admitted to hospital for cardiovascular reasons compared with controls, with a rate ratio of 1.08 (95% CI 1.06–1.11). Patients with surgically treated osteoarthritis of the hip have an increased risk of cardiovascular morbidity and mortality many years after the operation when compared with controls