Ultrasound as a diagnostic tool for femoral head containment disorders in children between one and 12 years of age

PURPOSE

Ultrasound has been used to diagnose hip dysplasia in neonates and to screen until the end of their first year. For older children, femoral head containment disorders such as developmental dysplasia of the hip, Legg-Calvé-Perthes disease or cerebral palsy are usually diagnosed with plain radiographs. The aim of the present study was to evaluate ultrasound in comparison with radiographic imaging in children up to age 12 years and to determine reference values for sonographic containment parameters.

METHODS

Hip ultrasound and radiographic imaging were acquired on the same day and then compared. As a reference, normal acetabular angle and acetabulum head index were determined on radiographs. Lateral cartilage distance (LCD), lateral head distance (LHD) and femoral head extrusion angle (HA) were measured on ultrasound images.

RESULTS

We included 96 patients with 167 healthy hips in the study. A total of 55 patients were female and 41 male. The mean age was 5.2 years (sd 3.3; 1.0 to 11.9). LCD_ultrasound, LHD_ultrasound and HA_ultrasound correlated significantly with radiographic parameters. The following ultrasound values were calculated as limits for impending loss of containment: LCD_ultrasound ≥ 6.5 mm, LHD_ultrasound ≥ 3.3 mm and HA_ultrasound ≥ 27.6°.

CONCLUSION

Ultrasound is a simple, radiation-free diagnostic tool to detect femoral head containment disorders, even in children older than one year. This study provides reference values for hip ultrasound in children up to 12 years.

LEVEL OF EVIDENCE

III.

Investigation of the priority among the roentgenogram measurements in acetabular dysplasia

PURPOSE

There are many radiographic parameters to evaluate developmental dysplasia of the hip joint (DDH); however, the priority between the parameters is unclear. We evaluated the priority of radiographic parameters in DDH.

METHODS

We retrospectively reviewed the radiographs of 82 consecutive patients aged above 85 years without hip osteoarthritis (OA; no osteoarthritis (NO) group), and 28 patients with early stage hip OA were set as the control group (OA group). We used the linear discriminant analysis (LDA) to consider the priority of the following parameters: acetabular roof obliquity (ARO), center-edge (CE) angle, Sharp angle, acetabular head index (AHI), and acetabular depth ratio (ADR).

RESULTS

The LDA of five different parameters revealed that the NO and OA groups could be almost distinguished with 83.6% accuracy (p < 0.0001, Wilks' lambda test). The standardized scoring coefficients were as follows: ARO, -0.23; CE, -0.43; Sharp, -0.29; AHI, 0.97; and ADR, 0.11. The AHI was particularly noticeable in the NO group.

CONCLUSION

Dissociation of the AHI in the OA group was significantly higher than that of the other parameters in the OA group compared to the parameters in the NO group. A small AHI may be a risk parameter for hip OA due to DDH.