Olson and Matta (1993) introduce the CT subchondral arc technique as a method for evaluating acetabular articular continuity after fracture. Using spherical geometry, they establish that CT imaging of the superior 10 mm of the acetabulum corresponds to the area assessed by 45° roof arc measurements, and propose three explicit CT-based criteria for selecting acetabular fractures appropriate for nonoperative management.
When evaluating an acetabular fracture for nonoperative management, use CT cuts from the vertex down through 10 mm (at 2–3 mm intervals) to confirm no fracture line disrupts the articular surface in this zone — if the superior 10 mm is intact, the femoral head is congruent out of traction, and any posterior wall component leaves ≥50% of the wall intact, nonoperative treatment is a defensible choice.
Remember that these criteria do not apply to both-column fractures, which require a separate assessment for secondary congruence.
Olson and Matta (1993) introduce the CT subchondral arc technique as a method for evaluating acetabular articular continuity after fracture. Using spherical geometry, they establish that CT imaging of the superior 10 mm of the acetabulum corresponds to the area assessed by 45° roof arc measurements, and propose three explicit CT-based criteria for selecting acetabular fractures appropriate for nonoperative management.
When evaluating an acetabular fracture for nonoperative management, use CT cuts from the vertex down through 10 mm (at 2–3 mm intervals) to confirm no fracture line disrupts the articular surface in this zone — if the superior 10 mm is intact, the femoral head is congruent out of traction, and any posterior wall component leaves ≥50% of the wall intact, nonoperative treatment is a defensible choice.
Remember that these criteria do not apply to both-column fractures, which require a separate assessment for secondary congruence.