Diagnostics of newborn's developmental hip joint dysplasia
About 4% of the newborns in Central Europe suffer from a developmental dysplasia of their hip joint, which expresses primarily by a flattend and small acetabular bearing area. An established procedure to diagnose this malformation was inaugurated by Reinhard Graf in the 1980s. It is based on the interpretation of one 2-D sonogram, that cuts the 3-D joint in an approximately frontal plane.
While the femoral head (2), which is not visible in ultrasound images, and the capsule (5) are not used for measurements, the most distal point (arrow) of the pelvic line (1), the acetabulum (3), and the acetabular labrum (4) must be identified to determine the Graf angels alpha (inclination angle) and beta (roof angle).
Methodical limitations can occur, because the joint’s geometry in a 2-D plane is assumed to represent the entire spatial joint. Using 3-D ultrasound instead, the entire spatial joint geometry can be registered. The animation demonstrates the visual enhancement of a B-mode gray-scale image volume by the overlay of automatically delineated diagnostically relevant anatomical structures:
- original gray-scale 3-D ultrasound image volume,
- overlay of the pelvis (red), acetabulum (blue), acetabular labrum (purple), and capsule (green),
- overlay of the femoral head (yellow), which is invisible in the B-mode images,
- the joint after rejection of the original gray-scale 3-D ultrasound image volume.
Co-operation: Hannover Medical School, Orthopedic Clinic, Hannover, Germany