From: Tübingen hip flexion splints for developmental dysplasia of the hip in infants aged 0–6 months
Type | Description | Bony Roof | Bony Rim | Cartilage Roof | α-angle | β-angle |
---|---|---|---|---|---|---|
I | Mature hip | Good | Angular/blunt | Covers the femoral head | ≥60 | < 77 |
IIa | Physiological (< 3 month) | Deficient | Rounded | Covers the femoral head | 50–59 | > 55 |
IIb | Delay of ossification (> 3 month) | Deficient | Rounded | Covers the femoral head | 50–59 | < 55 |
IIc | Critical hip | Severely deficient | Rounded to flattened | Still covers the femoral head | 43–49 | < 77 |
D | Decentering hip | Severely deficient | Rounded to flattened | Displaced | 43–49 | > 77 |
III | Dislocated hip | Poor | Flattened | Pressed upward, perichondrium slopes cranially | < 43 | > 77 |
IV | Dislocated hip | Poor | Flattened | Pressed downward, perichondrium is horizontal or dips caudally | < 43 |