An Evaluation of the Accuracy of Computer Assisted Surgery in Preoperatively Three Dimensionally Planned Periacetabular Osteotomies

Adults with unresolved developmental dysplasia of the hip (DDH) often warrant Pelvic Periacetabular Osteotomy (PAO). Making the correct osteotomies, and then finding the “ideal” position of the acetabular fragment is difficult, even for the experienced surgeon. Due to its 3-D nature, need for precision, and limited direct visualization of the surgical site, the PAO procedure is a good candidate for Computer Assisted Surgery (CAS). Using CAS, a virtual image is created, which is then used to navigate through the procedure in real time. Improved imaging hardware, along with intra-operative navigation systems have the potential to reduce complication rates, and lessen the learning curve in the inexperienced surgeon. PAO cuts have been made using intra-operative navigation and acetabular fragments have been positioned in pre-operative computer models. As of yet, modeled PAO cuts have not been used to navigate intraoperative cuts. Furthermore, modeled acetabular positioning has not been combined with intra-operative navigation to position fragments. The aim of this study is to prove the utility of pre-operative 3D imaging, PAO osteotomy planning and acetabular fragment positioning with computer software. These modeled images can be used to complete highly accurate and effective PAO surgeries.