Graf classified congenital hip dysplasia based on findings seen on ultrasonography of the femoral head and acetabulum. The author is from Landessonderkrankenhaus Stolzalpe in Austria.
Ultrasonographic measurements (page 736, Figure 2):
(1) baseline = line connecting the osseous acetabulum convexity and the point where the joint capsule, perichrondrium and iliac bone unite
(2) inclination line = line connecting the osseous convexity and the labrum acetabulare
(3) acetabulum roof line = line connecting the lower edge of the osseous convexity and os ileum
angle alpha =
= angle between the baseline and the acetabulum roof line
angle beta =
= angle between the baseline and the inclination line
|
Angle Alpha |
Angle Beta |
Classification |
|
> 60° |
< 55° |
Type I |
|
> 60° |
55 - 77° |
transition variant |
|
43 - 60° |
55 - 77° |
Type II |
|
< 43° |
> 77° |
Type III or IV |
where:
• There are 9 combinations for the different alpha and beta angles. Angle combinations not used are (1) alpha > 60°, beta > 77°; (2) alpha 43-60°, beta < 55°; (3) alpha 43-60°, beta > 77°; (4) alpha < 43°, beta < 55°; (5) alpha < 43°, beta 55-77°.
|
Type |
Features |
|
Type IIIa |
lateralization with weak or low echo = "sound hole" (Grade 1 subluxation without histologic transformation of the cartilage in the acetabular convexity) |
|
Type IIIb |
lateralization with dense echo (Grade 2 subluxation with histologic transformation of the cartilage in the acetabular convexity) |
|
Type IV |
femoral head completely dislocated, with an empty acetabulum or the femoral head lying in soft tissue; acetabulum convexity deformed and crushed |
where:
• The femoral head is only able to move laterally ("lateralization") if the cartilaginous acetabular convexity is deformed.
• In Type III the femoral head is used as the reference density.
Purpose: To examine the hip of an infant or young child using ultrasonography as described by Graf.
Specialty: Surgery, orthopedic, Pedatrics
Objective: imaging studies
ICD-10: Q65.8,
