CORRInsights®: Periacetabular Osteotomy Provides Higher Survivorship Than Rim Trimming for Acetabular Retroversion
The notion that acetabular retroversion can cause hip impingement and pain has been accepted for more than two decades . Studies [2, 5] have shown that structural defects of the hip likely involve both the acetabulum and a rotational abnormality of the entire inferior hemipelvis. The presence of the ischial, crossover, and posterior wall signs, and the association of retroversion with anterior-inferior iliac spine or subspine impingement further support the evidence that the entire hemipelvis is posteriorly rotated. Additionally, Steppacher and colleagues  showed that the acetabulum is not overgrown anteriorly and the size of the outer margins of the acetabular rim are normal while the size of the lunate surface may actually be smaller therefore a rim trimming would decrease a smaller than normal lunate surface.
Zurmühle and colleagues support the use of PAO, and consider it the best surgical treatment for patients with acetabular retroversion that had all radiographic signs of retroversion. This group, however, represented only 10% of all the patients that were treated at the authors’ institution during a 15-year period. Thus, the results of this study can only be applicable to this select group. In addition, although PAO is the preferred treatment for reorienting the acetabulum in patients with hip dysplasia, the procedure's complexity, steep learning curve, and potential for complications have limited its widespread use. Conversely, hip arthroscopy is commonly performed in patients with acetabular retroversion—the number of arthroscopic hip procedures has increased almost five-fold over the last decade, with the largest increase found in patients 18 to 34 years old . Considered a less-invasive surgical approach, hip arthroscopy in this setting might involve trimming the rim and reattaching the labrum with or without a concomitant femoral head and neck osteochondroplasty.
Zurmühle and colleagues not only question the value of rim trimming over anteverting PAO for this select patient group, but also the importance of surgical treatment of the labrum if the acetabulum is reoriented with a PAO, as none of the patients in the anteverting PAO group had labral refixation but most had favorable results.