The purpose of this study was to analyze the incidence of the different ultrasound phenotypes of developmental dysplasia of the hip (DDH), and to determine their subsequent course. A consecutive series of 28 092 neonates was screened and classified according to the Graf method as part of a nationwide surveillance programme, and then followed prospectively. Abnormal hips were followed until they became normal (Graf type I). Type IIb hips and higher grades were treated by abduction in a Tübinger orthosis until normal. Dislocated hips underwent closed or open reduction.Aims
Patients and Methods
The β-angle is a radiological tool for measuring the distance between the pathological head-neck junction and the acetabular rim with the hip in 90° of flexion in patients with femoroacetabular impingement. Initially it was measured using an open-chamber MRI. We have developed a technique to measure this angle on plain radiographs. Correlation analysis was undertaken to determine the relationship between the range of movement and the β-angle in 50 patients with femoroacetabular impingement and 50 asymptomatic control subjects. Inter- and intra-observer reliability of the β-angle was also evaluated. Patients with femoroacetabular impingement had a significantly smaller (p <
0.001) mean β-angle (15.6°, 95% confidence interval (CI) 13.3 to 17.7) compared with the asymptomatic group (38.7°, 95% CI 36.5 to 41.0). Correlation between internal rotation and the β-angle was high in the impingement group and moderate in the asymptomatic group. The β-angle had excellent inter- and intra-observer reliability in both groups. Our findings suggest that the measurement of the β-angle on plain radiography may represent a valid, reproducible and cost-effective alternative to open MRI in the assessment of the pathological bony anatomy in patients with cam, pincer and mixed femoroacetabular impingement.
We evaluated the impact of stereo-visualisation of three-dimensional volume-rendering CT datasets on the inter- and intraobserver reliability assessed by kappa values on the AO/OTA and Neer classifications in the assessment of proximal humeral fractures. Four independent observers classified 40 fractures according to the AO/OTA and Neer classifications using plain radiographs, two-dimensional CT scans and with stereo-visualised three-dimensional volume-rendering reconstructions. Both classification systems showed moderate interobserver reliability with plain radiographs and two-dimensional CT scans. Three-dimensional volume-rendered CT scans improved the interobserver reliability of both systems to good. Intraobserver reliability was moderate for both classifications when assessed by plain radiographs. Stereo visualisation of three-dimensional volume rendering improved intraobserver reliability to good for the AO/OTA method and to excellent for the Neer classification. These data support our opinion that stereo visualisation of three-dimensional volume-rendering datasets is of value when analysing and classifying complex fractures of the proximal humerus.
