Hip Preservation – 3D and Quantitative Imaging Laboratory

Hip Preservation

A young patient with hip dysplasia was brought to the attention of the 3DQ Lab by the Hip Preservation team at Lucille Packard Children’s Hospital (LPCH) at Stanford, who requested measurements and visualization to assist with their treatment. Hip dysplasia is a developmental condition in which the femoral head (the ball of the hip) fits too loosely into, or is not covered fully by, the hip socket (acetabulum). This can cause the patient to feel pain and pressure when using the joint, making walking difficult and unstable. If left untreated this can cause degeneration of the joint tissue or femoroacetabular impingement (FAI), a condition where the femoral head and acetabulum rub together.

A CT scan was acquired of the patient’s bony pelvis anatomy, and a Stanford 3DQ Lab Technologist began by creating batches of images that were parallel, perpendicular, and oblique to the right posterior acetabulum. Radial batches of the right femur, and rotational Volume Rendered (VR) movies of the pelvis were additionally created. Visit our Batching page to learn more about this technique: https://3dqlab.stanford.edu/technique-of-the-week-batching/

Figure A: Radial rotational batch consisting of a MPR spinning the image data on an axis. Displays the relationship between the femoral head and the acetabulum.

Figure B: Coronal and sagittal batches demonstrate the relationship of the acetabulum and femoral head from different angles.

Figure C: VR rotational series of the superior femur used for visualizing the femoral head, and lesser and greater trocanters.

Figure D: VR rotational series of the pelvis, with the right femur removed to expose the acetabulum.

A series of angular impingement measurements were created to demonstrate the movement mechanics of the joint, and identify locations where contact may occur between the femoral head and acetabulum. The angular measurements performed were:

• Distal Femoral Angle (DFA): Measurement used to evaluate the alignment of the mechanical axis of the femur and knee joint line. An abnormal DFA may indicate the femur is not properly aligned with the knee joint.

• Acetabular Version: The measured angle formed between the anterior and posterior edges of the acetabulum. The measurement is used to determine the degree of hip socket coverage, and the relationship between the acetabulum and femoral head.

• Proximal Femoral Torsion: Measurement used to evaluate the degree of twist in the femoral neck in relation to the femoral head. A normal proximal femoral torsion measurement ranges from 8 to 15 degrees of anteversion, meaning that the femoral neck is angled forward relative to the femoral shaft.

Figure E (Right): Examples of the acetabular version, distal femur, and proximal femoral torsion angle measurements.

The rotational movies, rotational batches, and impingement measurements were provided to the Hip Preservation Team and used to inform decisions related to treatment. A comprehensive approach was taken to determine the proper treatment path, including measurements, patient’s age, severity of the condition, and the goals of the treatment.

To learn more about LPCH’s Hip Preservation program visit their page here: https://www.stanfordchildrens.org/en/service/hip-preservation

3DQ Lab – Grant Building

3DQ Lab – Clark Building

Learn More About the Lab