Meta-analysis assessing the sensitivity and specificity of 18F-FDG PET/CT for the diagnosis of prosthetic valve endocarditis (PVE) using individual patient data (IPD).

IMPORTANCE: The use of 18F-FDG PET/CT in diagnostic algorithms for PVE has increased since publication of studies and guidelines advocating its use. The assessment of test accuracy has been limited by small study sizes. We undertook a systematic review using individual patient data (IPD) meta-analysis techniques. OBJECTIVE: To estimate the summary sensitivity and specificity of 18F-FDG PET/CT in diagnosing PVE. We also assessed the effect of patient factors on test accuracy as defined by changes in the odds ratios associated with each factor. The effect of the PET/CT study on the final diagnosis was also assessed when compared to the preliminary Duke classification to determine in which patient group 18F-FDG PET/CT had the greatest utility. STUDY SELECTION: Studies were included if PET/CT was performed for suspicion of PVE and IPD of both the PET/CT result and final diagnosis defined by a gold-standard assessment was available. There were 3 possible final diagnoses ("definite PVE," "possible PVE," and "rejected PVE"). RESULTS: Seventeen studies were included with IPD available for 537 patients (from 538 scans). The summary sensitivity and specificity were 85% (95% CI 74.2%-91.8%) and 86.5% (95% CI 75.8%-92.9%) respectively when patients with final diagnosis of "possible PVE" were classified as positive for PVE. When this group was classified as negative for PVE, sensitivity was 87.4% (95% CI 80.4%-92.1%) and specificity was 84.9% (95% CI 71.5%-92.6%). Patients with a known pathogen (especially coagulase negative staphylococcal species), elevated CRP, a biological or aortic valve infection appeared more likely to have an accurate PET/CT diagnosis. Those with a mechanical valve, prior antibiotic treatment or a transcatheter aortic valve replacement valve were less likely to have an accurate test. Time since valve implantation and the presence of surgical adhesive did not appear to affect test accuracy. Of the patients with a preliminary Duke classification of "possible PVE," 84% received a more conclusive final diagnosis of "definite" or "rejected" PVE after the PET/CT study. CONCLUSIONS AND RELEVANCE: 18F-FDG PET/CT has high sensitivity and specificity in diagnosing PVE and the diagnostic utility is greatest in patients with a preliminary Duke classification of "possible PVE." Some patient factors appear to affect test accuracy, though these results should be interpreted with caution given low patient numbers for subgroup analyses.

Fixation Method for Hip Arthroplasty Stem Following Hip Fracture: A Population-Level Cost-Effectiveness Analysis.

BACKGROUND: Hip arthroplasty is increasing in Australia. The number of procedures for fractured neck of femur was 7500 in 2017. Best practices for fixation method and procedure type require scrutiny. This paper is about the costs and health outcomes of cemented and uncemented hemiarthroplasty and total hip arthroplasty at a national level. METHODS: We created a Markov model for patients <75, aged 75-85, and over 85. Expected costs and health outcomes over 5 years from a decision to change from existing practice to a best practice policy in which all patients with fractured neck of femur received the same fixation method based on age and type of arthroplasty are estimated. The model was populated using prevalence and incidence data from the Australian Orthopedic Association National Joint Replacement Registry, costs from Metro North Hospital and Health Service in Queensland, and probabilities and utilities from the literature. We simulated the uncertainties in outcomes with probabilistic sensitivity analysis. RESULTS: We found that uncemented stem procedures were more costly and provided worse health outcomes compared to cemented stem fixation for hemiarthroplasty and total hip arthroplasty for all age groups. Moving from existing practice to cemented stem arthroplasty could save the Australian health system $2.0 million over 5 years with a gain of 203 quality-adjusted life years. CONCLUSION: We suggest that consideration be given to cemented fixation of the femoral stem for patients receiving both hemiarthroplasty and total hip arthroplasty for fractured neck of femur. Best practice guidelines focused on cost-effectiveness should recommend cemented stem fixation to both save costs and improve patient quality of life.

Rotational Malalignment of the Knee Extensor Mechanism: Defining Rotation of the Quadriceps and Its Role in the Spectrum of Patellofemoral Joint Instability.

Osseous rotational malalignment of the lower limb is widely accepted as a factor contributing to patellofemoral instability, particularly in pediatric patients. Patellar instability occurs when the lateral force vector generated by the quadriceps exceeds the restraints provided by osseous and soft-tissue anatomy. The anatomy and activation of the quadriceps are responsible for the force applied across the patellofemoral joint, which has previously been measured using the quadriceps (Q)-angle. To our knowledge, the contribution of the quadriceps anatomy in generating a force vector in the axial plane has not previously been assessed. The primary aim of this study was to introduce the quadriceps torsion angle, a measure of quadriceps rotational alignment in the juvenile population. The secondary aims of this study were to determine the inter-assessor and intra-assessor reliability of the quadriceps torsion angle in the juvenile population and to investigate whether a large quadriceps torsion angle is a classifier of patellar dislocator group membership in a mixed cohort of patellar dislocators and typically developing controls. METHODS: Participants between the ages of 8 and 19 years were recruited as either controls or recurrent patellar dislocators. A total of 58 knees in both groups were assessed from magnetic resonance imaging scans of the entire lower limbs. Axial cuts midway between the superior aspect of the femoral head and the articular surface of the medial femoral condyle were used to calculate the proximal reference for the quadriceps torsion angle. The quadriceps torsion angle was defined as the angle between the line connecting the anterior aspect of the sartorius and the junction of the anterior and posterior compartments at the lateral intermuscular septum and the posterior condylar axis line. Inter-assessor reliability was calculated using the intraclass correlation coefficient. The relationship between the quadriceps torsion angle and the femoral torsion was assessed in the entire cohort. These values were compared between the control group and the dislocator group to determine if the raw values or an interplay between the 2 factors played a role in the pathoanatomy of recurrent patellofemoral dislocation. RESULTS: The quadriceps torsion angle was a reproducible assessment in both inter-assessor and intra-assessor reliability analyses. A moderate positive correlation (r = 0.624; p < 0.01) was found between the femoral torsion and the quadriceps torsion angle. Although the quadriceps torsion angle was a fair classifier of patellar dislocation group membership, femoral torsion was not. CONCLUSIONS: This study has quantified the rotational alignment of the extensor mechanism using the quadriceps torsion angle. The measurement is shown to be reliable and reproducible and a fair classifier of patellofemoral instability. CLINICAL RELEVANCE: This article introduces an objective measure of soft-tissue rotational malalignment in the pathogenesis of recurrent patellar dislocation.

FDG PET/CT of Metabolic Myopathy With Posttreatment Follow-up.

A 38-year-old woman presented with extreme fatigue and multiple lung nodules. She was referred for a PET/CT, which demonstrated multiple FDG-avid pulmonary nodules and lymph nodes with intense uptake within multiple muscle groups predominantly involving the paraspinal muscles and muscles of mastication. Histopathology of a paraspinal muscle biopsy revealed increased skeletal muscle lipid stores and increased mitochondria with normal morphology. This abnormality is seen in metabolic myopathy due to a disorder of fatty acid oxidation. Transbronchial biopsy showed no evidence of sarcoidosis. The patient was commenced on carnitine and riboflavin supplementation, and a follow-up PET/CT was performed.

Performance status of male and female advanced cancer patients is independently predicted by mid-upper arm circumference measurement.

In the advanced cancer patient, performance status has considerable prognostic power. Karnofsky performance status, together with variables reported to influence its score, was measured in advanced gastrointestinal cancer patients (n = 148). For male and female patients, age, body mass index, weight loss, triceps skinfold thickness, mid-upper arm circumference, albumin, C-reactive protein, and tumor type and stage were regressed against Karnofsky performance status. On multiple regression analysis, only mid-upper arm circumference and log10 C-reactive protein in men (r2 = 0.462, P < 0.0001) and only mid-upper arm circumference and weight loss in women (r2 = 0.485, P < 0.01) were independent predictors of Karnofsky performance status. There was a significant partial correlation, with gender as a covariable, between log10 C-reactive protein and albumin (r = -0.530, P < 0.0001) and mid-upper arm circumference (r = -0.269, P = 0.035) and weight loss (r = 0.286, P = 0.024). The results of the present study indicate that mid-upper arm circumference is a major factor that influences performance status in male and female patients with advanced gastrointestinal cancer.