CARTILAGE CONTACT MECHANICS FOLLOWING TREATMENT OF ACETABULAR RETROVERSION WITH PERI-ACETABULAR OSTEOTOMY: A CASE STUDY

摘要

Acetabular retroversion is a form of dysplasia where the acetabulum is tilted excessively in the anterior plane with a loss of posterior coverage. Excessive anterior coverage may cause impingement, and reduced acetabular coverage may increase cartilage contact pressures in the posteroinferior region, thereby causing hip osteoarthritis (OA). Treatment of retroversion is controversial: patients receive debridement of the anterior acetabular rim or posteriorly directed reorientation of the acetabulum via peri-acetabular osteotomy (PAO). Improved methods to quantify pre- and post-operative cartilage mechanics could be used to standardize treatment. Subtle irregularities in contact geometry and congruency create complex stresses patterns [1], even in normal hips [2]. Thus, despite improvements in coverage, the PAO procedure may increase cartilage stresses. A few studies have modeled dysplastic hips before and after PAO, but they used spherical geometry, constant cartilage thickness, rigid bones, and only studied traditional dysplasia [3-4]. In this study we used patient-specific and idealized/spherical FE models with deformable bones to quantify pre- and post-operative cartilage contact stresses in a patient treated for acetabular retroversion with a PAO.