Adolescent and Young Adult Hip Dysplasia

David D. Spence, Derek M. Kelly, Marc J. Mihalko and James L. Guyton


Curr Orthop Pract. 2013;24(6):567-575. 

In This Article

Natural History

The natural history of severe untreated hip dysplasia is the development of secondary osteoarthritis as evidenced by many reports in the literature. The natural history of less severe untreated hip dysplasia has not been as clearly defined. Murphy et al.[15] attempted to define criteria on which to base treatment of less severe dysplasia. They studied the contralateral hip in patients who had a total hip replacement for osteoarthritis secondary to dysplasia in an attempt to identify radiographic findings that would predict the outcome of untreated dysplasia. In the overall analysis, they compared 74 patients who developed severe osteoarthritis in the contralateral hip with 43 who did not. All seven radiographic parameters measured by these authors differed significantly (P<0.0001) between the osteoarthritis and nonarthritis groups (center edge angle, 7 ± 121 compared with 34 ± 4mm; mean vertical distance, 10 ± 8mm compared with 1 ± 2mm; mean lateral distance, 13 ± 4mm compared with 6 ± 2mm; peak-to-edge distance, 3±5mm compared with 16±4mm; femoral-head extrusion index 36 ±12% compared with 12 ± 8%; acetabular index depth-to-width 31 ± 7% compared with 48 ± 6%; acetabular index weightbearing zone, 25 ± 101 compared with 6 ± 61, respectively; Figure 1).

Figure 1.

Radiographic measurements. A, Acetabular index depth-to-width. B, Acetabular index of the weight bearing zone (Tö nnis). Angle is formed between a line parallel to weightbearing dome and line parallel to interteardrop line. C, Femoral head extrusion index is percentage calculated by dividing horizontal distance of part of femoral head lateral to edge of acetabulum (A) by total horizontal width of femoral head (A+B) and multiplying by 100: (A/[A+B] × 100). D, Peak-to-edge distance (D). Horizontal line parallel to interteardrop line is drawn across apex of acetabulum (most proximal point of dome). Horizontal distance from apex to acetabular edge is measured. E, Lateral center-edge angle of Wiberg. Angle formed by line drawn perpendicular to line through the center of the femoral heads and line from center of femoral head to superior border of the acetabulum. F, Anterior center edge angle of Lesquesne. Angle formed by intersection of vertical line through center of femoral head and line from center of femoral head to anterior sourcil on false profile view. G, Cross-over sign. On anteroposterior view, outlines of anterior and posterior wall should meet superiorly and laterally. H, Lateral subluxation is measured from the lateral side of teardrop to medial edge of femoral head. I, Superior subluxation is measured vertically from inferior edge of acetabulum to inferior margin of femoral head. A-D and H-I reprinted with permission from: Murphy SH, et al.15 J Bone Joint Surg. 1995; 77(A):985–989.