Femoroacetabular Impingement: How to perform

Last updated on July 6 2022

Description

Femoroacetabular impingement (FAI) is a condition in which extra one grows along the femur and/or acetabulum. Because they do not fit together perfectly, the bones rub against each other causing pain. To correct FAI deformities the surgeon may perform surgery (usually arthroscopy) to remove the bone volume in excess. 

• Pincer type: the excess of bone extends out over the normal rim of the acetabulum;
• Cam type: the excess of bone is presented around the femoral head and it cannot rotate smoothly inside the acetabulum;
• Combined type: a combination of the Pincer and Cam types.

Measurements

The measurements made by the procedure are displayed in the image: 

• Central Edge Angle (CEA): the angle between the femoral vertical line and the central edge line;
• Alpha Angle (Alpha): the angle between the femoral neck-line and the femoral junction head/neck-line.

Auxiliary references 

To show this procedure, PeekMed® needs additional references:

• Hilgenreiner’s line: a horizontal line through the teardrops (or triradiate cartilage in children) of the acetabulum;

• Femoral vertical line: a perpendicular line to Hilgenreiner’s line that crosses the center of the femoral head;

• Central edge line: a line between the lateral edge of the acetabulum and the center of the femoral head;

• Femoral neck-line: a line that passes through the center of the femoral head and neck;

• Femoral head/neck junction line: a line that  passes through the center of the femoral head and its head/neck junction;
• Femoral head: a circumference surrounding the femoral head.