Developmental dysplasia of the hip: Graf ultrasound is still the standard

More than four decades after Reinhard Graf described his method, ultrasound remains the central tool for screening hip dysplasia in newborns.

Described by Reinhard Graf in 1980, the method that assesses the bony and cartilaginous coverage of the femoral head by the acetabulum — through the alpha and beta angles — remains the most widely used ultrasound technique for screening developmental dysplasia of the hip (DDH).

The angles that define the classification

The alpha angle measures the inclination of the acetabular roof relative to the iliac baseline — normal values are above 60°. The beta angle assesses cartilaginous coverage. Together, they classify the hip into Graf types I through IV, which directly guide management.

Why systematic screening matters

Populations undergoing universal ultrasound screening identify and treat more cases of dysplasia than populations screened by clinical exam alone — the difference has been estimated at 5–7% versus 2% in some studies. The technique, however, requires a standardized imaging plane and correct recognition of anatomical landmarks to be reproducible.