Roof Arc Measurements For Acetabular Fx

Computerized tomography ct of the superior 10 mm of the acetabular articular surface evaluates the area equivalent to roof arc measurements of 45.

Roof arc measurements for acetabular fx.

We present the method for measuring the roof arc on radiographs and estimating this arc on ct scans. Average medial anterior and posterior acetabular roof arc angles of the absawba of 94 normal acetabulum were 39 09 7 41 42 49 8 15 and 55 26 10 08 degrees respectively. Less than 39 42 and 55 of medial anterior and posterior acetabular roof arc angles involve absawba of the femoral head. In acetabular fracture a medial roof arc angle less than 46 degrees an anterior roof arc angle less than 52 degrees or posterior roof arc angle less than 61 degrees is considered to be involved in a weight bearing area.

For patients with acetabular fractures the extent to which a fracture involves the weight bearing dome has been estimated with the roof arc measurement obtained on radiographs and computed tomographic ct studies. The criteria to treat acetabular fractures operatively versus nonoperatively continue to evolve. Roof arc measurements roof arc measurements are defined as the angle formed by a line parallel to the patient passing through the center of the acetabulum and a line from the center of the acetabulum to the fractured area of the dome.