The ischial spine sign: does pelvic tilt and rotation matter?

Although the ischial spine sign (ISS) has been advocated to detect acetabular retroversion, it is unknown whether the sign is valid on anteroposterior (AP) pelvic radiographs with tilted or rotated pelves. We therefore evaluated reliability of the ISS as a tool for diagnosing acetabular retroversion in the presence of considerable pelvic tilt and/or malrotation. We obtained radiographs of 20 cadaver pelves in 19 different malorientations resulting in 380 pelvis images (760 hips) for evaluation. In addition, 129 clinical radiographs of patients' hips that had varying pelvis orientations were reviewed. We found an overall sensitivity of 81% (90%), specificity of 70% (71%), positive predictive value of 77% (80.7%), and negative predictive value of 75% (85%) in the cadaver (patient) hips. Our data suggest the ISS is a valid tool for diagnosing acetabular retroversion on plain radiographs taken using a standardized technique regardless of the degree of pelvic tilt and rotation.

Pulse-front tilt for short-wavelength lasing by means of traveling-wave plasma-excitation

Generation of coherent short-wavelength radiation across a plasma column is dramatically improved under traveling-wave excitation (TWE). The latter is optimized when its propagation is close to the speed of light, which implies small-angle target-irradiation. Yet, short-wavelength lasing needs large irradiation angles in order to increase the optical penetration of the pump into the plasma core. Pulse-front back-tilt is considered to overcome such trade-off. In fact, the TWE speed depends on the pulse-front slope (envelope of amplitude), whereas the optical penetration depth depends on the wave-front slope (envelope of phase). Pulse-front tilt by means of compressor misalignment was found effective only if coupled with a high-magnification front-end imaging/focusing component. It is concluded that speed matching should be accomplished with minimal compressor misalignment and maximal imaging magnification.

Estimation of pelvic tilt on anteroposterior X-rays--a comparison of six parameters

OBJECTIVE: To compare six different parameters described in literature for estimation of pelvic tilt on an anteroposterior pelvic radiograph and to create a simple nomogram for tilt correction of prosthetic cup version in total hip arthroplasty. DESIGN: Simultaneous anteroposterior and lateral pelvic radiographs are taken routinely in our institution and were analyzed prospectively. The different parameters (including three distances and three ratios) were measured and compared to the actual pelvic tilt on the lateral radiograph using simple linear regression analysis. PATIENTS: One hundred and four consecutive patients (41 men, 63 women with a mean age of 31.7 years, SD 9.2 years, range 15.7-59.1 years) were studied. RESULTS: The strongest correlation between pelvic tilt and one of the six parameters for both men and women was the distance between the upper border of the symphysis and the sacrococcygeal joint. The correlation coefficient was 0.68 for men (P<0.001) and 0.61 for women (P<0.001). Based on this linear correlation, a nomogram was created that enables fast, tilt-corrected cup version measurements in clinical routine use. CONCLUSION: This simple method for correcting variations in pelvic tilt on plain radiographs can potentially improve the radiologist's ability to diagnose and interpret malformations of the acetabulum (particularly acetabular retroversion and excessive acetabular overcoverage) and post-operative orientation of the prosthetic acetabulum.

Do patients respect the line? Transgression of boundaries reported by Swiss general practitioners

OBJECTIVE: Transgression of boundaries in the relationship between physician and patient is commonly studied with patient as victim and physician as transgressor. A recent survey in the U.S. reported that almost 90% of physicians face transgression by patients over one year. Incidents happened mainly through verbal abuse, disregarding privacy, and overly affectionate behavior. Since this incidence seems to be alarmingly high, we were interested to analyze how often general practitioners in Switzerland experience transgression by patients. METHODS: 24% of the members of the Swiss Society of Internal Medicine (SGIM) and of the Swiss Society of General Medicine (SGAM) (n=675/2781) responded to an internet-based survey which asked for experiences of transgression by patients and for physicians' responses to transgression in the last 12 months. RESULTS: 81% of responding physicians experienced transgression over the period of one year. Analyzing the frequency of incidents per physician per year, the most common forms of transgression were 'use of physician's first name' (7.7/y), 'asking personal questions' (1.8/y), 'being verbally abusive' (1.5/y), and 'being overly affectionate' (1.4/y). Calculated incidence of transgression was 3 per 1000 patient contacts. 39% of physicians decided to ignore the incident, 37% discussed the event openly. Transgression led to dismissal of patients in 13% of events. CONCLUSION: Transgression even in mild and modest form is a rare phenomenon in Swiss practices. PRACTICE IMPLICATION: The Swiss data do not suggest that there is a specific risk for Swiss practitioners to be exposed to major transgression for which they should specifically be prepared for example in communication skills trainings.