Roof Arc Measurements For Acetabular Fx

The technique of roof arc measurements was developed to identify the extent of superior acetabulum left intact after fracture.

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. Less than 39 42 and 55 of medial anterior and posterior acetabular roof arc angles involve absawba of the femoral head. 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. 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.

These roof arc angle values may be used as a surgical guideline for an acetabular fracture around the 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. 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.