Type | Alpha angle | Acetabular modelling | Bony acetabular rim | Beta angle | Labrum | Position of femoral head | Age |
---|---|---|---|---|---|---|---|
|
>60° | good | sharp | <55° | good femoral coverage | central | all |
|
>60° | good | slightly rounded | <55° | good femoral coverage | central | all |
|
50–59° | deficient | rounded | <55° | coverage femoral head | central | <3 mo |
|
50–59° | deficient | rounded | <55° | coverage femoral head | central | >3 mo |
|
43–49° | severely deficient | rounded/flat | >55 but <77° | still coverage femoral head | stable or unstable | all |
|
43–49° | severely deficient | rounded/flat | >77° | still coverage femoral head | decentering | all |
|
<43° | poor | flat | labrum pressed upwards | eccentric | all | |
|
<43° | poor | flat | labrum pressed downwards/disappears | eccentric | all |
Country | Type of ultrasound screening | Timing (week) |
---|---|---|
|
selective | 12 |
|
selective | <12 |
|
selective | <4 |
|
selective | 6–8 |
|
universal | 4–12 |
|
universal | 1 6–8 |
|
universal | <5 |
|
universal | Risk factor + 1–2 Risk factor – 4–5 |
|
selective | 1–12 |
|
selective | 1 |
|
selective | <6 |
|
universal | Risk factor + 1–2 Risk factor – 6 |
|
universal | 1–12 |
|
selective | 6 |
|
selective | 6 |
Acetabular modelling: good/adequate/deficient/poor |
Bony acetabular rim: sharp/rounded/flat |
Alpha angle (°) |
Femoral head: ossification no/symmetric/asymmetric |
Femoral head position: centric – eccentric |
Beta angle (°) |