Table 2.

Preoperative considerations prior to periacetabular osteotomy (PAO) surgery

Preoperative checklist	Recommendations
Acetabular labral tears	Significant labral pathology (full thickness tears, large degenerative labrums) can remain symptomatic following PAO in spite of the mechanical offloading. The labrum should be evaluated and repaired as indicated by arthrotomy or arthroscopy.
Anterior inferior iliac spine (AIIS)	The AIIS should be evaluated on preoperative anteroposterior pelvis and faux profil radiographs. As the acetabular fragment is moved, a prominent AIIS will be placed into a position of impingement. Movement should be carefully checked after reorientation in these cases.
Femoral cam deformity	Cam deformities are seen in 30% to 40% of acetabular dysplasia cases. Impingement is a known cause of early PAO failures, so significant cam deformities should be addressed at the time of surgery via arthrotomy or arthroscopy.
Joint congruity	Preoperative Von-Rosen (flexion/abduction/internal rotation) views should be obtained in severe deformities. If concentric reduction not attained on this functional view, concomitant femoral-sided osteotomy can be considered.