The Reverse Periacetabular Osteotomy: Indications and Surgical Technique

Abstract

Pincer-type femoroacetabular impingement may be caused by acetabular retroversion or global acetabular overcoverage. Recent evidence suggests that open or arthroscopic acetabular rim resection for pincer-type impingement may remove essential weight bearing lunate cartilage with preliminary clinical results suggesting improved hip survivorship with anteverting periacetabular osteotomy (PAO) rather than rim resection. In cases of symptomatic pincer-type femoroacetabular impingement related to global acetabular overcoverage (lateral and anterior center edge angles >40°), a true reverse PAO, which flexes and abducts the acetabular fragment, may be used to reduce anterior and lateral coverage. We present the novel technique for true reverse PAO. Modifications of the reverse PAO when compared to the traditional PAO include: different orientation of the posterior column and ischial osteotomy cuts; the distinct corrective maneuvers to displace the acetabular fragment; bone resection from the iliac osteotomy surfaces to facilitate adequate correction; additional osteoplasty of the anterior ilium to prevent postoperative pressure on the femoral nerve, and steps to prevent subsidence into and nonunion of the posterior column gap created through correction. The reverse PAO is a powerful tool for surgical correction of global acetabular overcoverage. Further study is needed to demonstrate clinical efficacy and outcomes of this modification.