Variation in Treatment for Trapeziometacarpal Arthrosis

Background: Treatment recommendations for trapeziometacarpal (TMC) arthrosis are highly variable from surgeon to surgeon. This study addressed the influence of viewing radiographs on a decision to offer surgery for TMC arthrosis. Methods: In an online survey, 92 hand surgeons viewed clinical scenarios and were asked if they would offer surgery to 30 patients with TMC arthrosis. Forty-two observers were randomly assigned to review clinical information alone and 50 to review clinical information as well as radiographs. The degree of limitation of daily activities, time since diagnosis, prior treatment, pain with grind, crepitation with grind, and metacarpal adduction with metacarpophalangeal hyperextension were randomized for each patient scenario to determine the influence of these factors on offers of surgery. A cross-classified binary logistic multilevel regression analysis identified factors associated with surgeon offer of surgery. Results: Surgeons were more likely to offer surgery when they viewed radiographs (42% vs. 32%, P = 0.01). Other factors associated variation in offer of surgery included greater limitation of daily activities, symptoms for a year, prior splint or injection, deformity of the metacarpophalangeal joint. Factors not associated included limb dominance, prominence of the TMC joint, crepitation with the grind test, and pinch and grip strength. Conclusion: Surgeons that view radiographs are more likely to offer surgery to people with TMC arthrosis. Surgeons are also more likely to offer surgery when people do not adapt with time and nonoperative treatment. Given the notable influence of surgeon bias, and the potential for surgeon and patient impatience with the adaptation process, methods for increasing patient participation in the decision-making process merit additional attention and study

Evolution and scaling of atrioventricular conduction time in mammals. [Pt. 2]

Changes of the PR interval (atrioventricular delay) in relation to changes of heart size in mammalian species (scaling) confront us with a perplexing lack of understanding of an essential funetion of the heart. The PR interval controls the duration of late diastolic blood flow from the atria to the ventricles. There is good evidence that blood flow velocity is fairly constant in all mammalian species, meaning it does not scale. Also, in all mammalian species, the mitral orifice does not offer any resistance to atrioventricular blood flow. It follows that blood flow duration is directly dependent on the distance between the atria and the ventricles. Although the heart is not a cube, this distance is defined as the third root of heart mass. The third root of any value changes little in relation to the value itself. This simple mathematic fact is an easy explanation for PR interval behavior in relation to heart and/or body size. However, the atrioventricular intranodal electrophysiology of this behavior is not known

Velocity profiles in large arteries

no abstract

A new method for microdensitometer slit length correction of radiographic noise power spectra

When the power spectrum of radiographic noise is estimated from scans obtained with a microdensitometer equipped with a rectangular slit, a bias is present due to the finite length of this slit. A method to correct for this bias was developed and was tested on both a simulated and a measured spectrum. No bias remains with our method, in situations where a conventional method shows a significantly biased result. Good agreement was found with the synthesized slit method, described by Sandrik and Wagne