Acetabular Dysplasia

Abstract

A simple method of measuring the degree of acetabular development in the radiograph of the adult pelvis is described and arguments for its validity are advanced. This measurement is referred to as the acetabular angle. The normal values for this angle are between 33 and 38 degrees. Angles below 32 degrees are uncommon and probably of no clinical significance, whereas angles from 39 to 42 degrees are in the upper limit of normality. An angle of 47 degrees is shown in a hip with congenital subluxation. The prognosis for hip joints with acetabular angles between 42 and 47 degrees is under investigation.

Radiological findings for hip dysplasia at skeletal maturity. Validation of digital and manual measurement techniques

“…measured all images three times, twice using the digital technique and once using the manual AgfaWeb1000 system. Before performing the measurements, all three observers agreed on the precise definitions of landmarks to be used for all the measurements, according to descriptions from the original literature [4][5][6][7][8][13][14][15][16][17][18][19].…”

“…A correctly performed pelvic radiograph with corresponding measurements is fundamental for the radiological diagnosis. The center-edge (CE) angle of Wiberg [4], Sharp's angle [5], the acetabular depth-width ratio [6,7] and the femoral head extrusion index [8] are The acetabular depth-width ratio (ADR) defines the ratio of the distance between the inferior teardrop point and the lateral acetabular rim, and the depth of the acetabulum. b The position of the femoral head to the acetabular cavity was defined using Wiberg's center-edge (CE) angle, a modification of this (Ogata's angle), and the femoral head extrusion index (FHEI).…”

Pelvic orientation and assessment of hip dysplasia in adults

“…We assessed hip morphology on AP pelvis radiographs by 1) Wiberg's center-edge (CE) angle (Wiberg 1939), 2) Sharp's angle (Sharp 1961), 3) the femoral head extrusion index of Heyman and Herndon (FHEI;Heyman and Herndon 1950), 4) Goodman's coordinate system (Goodman 1990), and 5) the acetabular depth ratio of Murray and Stulberg (ADR;Murray 1965, Stulberg et al 1975 (Figure 2). The lateral margin of the sourcil was used to denote the lateral acetabular rim in relevant measurements.…”

Hip arthroplasty for congenital dislocation

“…Dysplasia is described as the inclination of the pelvic acetabulum to a transverse line (Sharp 1961) or the angle between the lateral edge to the head center and a vertical line (Wiberg 1939). Both methods describe sufficiently the borderline between the dysplastic and the normal acetabulum, but they do not point out the functional center of the hip, which is essential for determining the "high dislocations."…”