Roof Arc Measurements Acetabular Fractures

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 acetabular fractures.

If nonoperative treatment is to be considered the head should remain congruous with the roof of the acetabulum on the three views of the pelvis with the patient out of traction and all roof arc. However when there is an associated posterior wall fracture the radiographic roof arc measurement cannot be used at the preoperative period. 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. In acetabular fracture a medial roof arc angle less than 46 an anterior roof arc angle less than 52 or posterior roof arc angle less than 61 is considered to be involved in a weight bearing area.

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. The medial roof arc angle was 46 6 3 degrees anterior roof arc angle was 52 7 0 degrees and posterior roof arc angle was 62 degrees 8 5 degrees. 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.

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 technique of roof arc measurements was developed to identify the extent of superior acetabulum left intact after fracture. Defined as an intact subchonral ring in the superior 10 mm of the acetabulum 2 mm incongruity in the articular segment is considered unstable. It is generally accepted that intra operative roof arc angles of 45 or more represents a satisfactory restitution of the weight bearing portion of the acetabulum cavity 12.

Less than 39 42 and 55 of medial anterior and posterior acetabular roof arc angles involve absawba of the femoral head. With peekmed a powerful 3d pre operative. 2 mm fine cuts on axial view. The criteria to treat acetabular fractures operatively versus nonoperatively continue to evolve.