Is Anterior Rotation of the Acetabulum Necessary to Normalize Joint Contact Pressure in Periacetabular Osteotomy? A Finite-element Analysis Study

• Published in: Clinical orthopaedics and related research 2022-01, Vol.480 (1), p.67-78
• Main Authors: Kitamura, Kenji, Fujii, Masanori, Iwamoto, Miho, Ikemura, Satoshi, Hamai, Satoshi, Motomura, Goro, Nakashima, Yasuharu
• Format: Article
• Language: English
• Subjects: Acetabulum; Acetabulum - diagnostic imaging; Acetabulum - surgery; Adult; Arthritis; Biomechanical Phenomena; Bone dysplasia; Bone surgery; Cartilage diseases; Clinical Research; Female; Finite Element Analysis; Finite element method; Hip; Hip dislocation; Hip Dislocation - diagnostic imaging; Hip Dislocation - surgery; Humans; Imaging, Three-Dimensional; Mathematical models; Middle Aged; Osteoarthritis; Osteotomy; Osteotomy - methods; Patients; Pressure; Risk Factors; Standing Position; Tomography, X-Ray Computed; Weight-Bearing
• ISSN: 0009-921X; 1528-1132
• DOI: 10.1097/CORR.0000000000001893

Inappropriate sagittal plane correction can result in an increased risk of osteoarthritis progression after periacetabular osteotomy (PAO). Individual and postural variations in sagittal pelvic tilt, along with acetabular deformity, affect joint contact mechanics in dysplastic hips and may impact the direction and degree of acetabular correction. Finite-element analyses that account for physiologic pelvic tilt may provide valuable insight into the effect of PAO on the contact mechanics of dysplastic hips, which may lead to improved acetabular correction during PAO. We performed virtual PAO using finite-element models with reference to the standing pelvic position to clarify (1) whether lateral rotation of the acetabulum normalizes the joint contact pressure, (2) risk factors for abnormal contact pressure after lateral rotation of the acetabulum, and (3) whether additional anterior rotation of the acetabulum further reduces contact pressure. Between 2016 and 2020, 85 patients (92 hips) underwent PAO to treat hip dysplasia. Eighty-two patients with hip dysplasia (lateral center-edge angle < 20°) were included. Patients with advanced osteoarthritis, femoral head deformity, prior hip or spine surgery, or poor-quality images were excluded. Thirty-eight patients (38 hips) were eligible to participate in this study. All patients were women, with a mean age of 39 ± 10 years. Thirty-three women volunteers without a history of hip disease were reviewed as control participants. Individuals with a lateral center-edge angle < 25° or poor-quality images were excluded. Sixteen individuals (16 hips) with a mean age of 36 ± 7 years were eligible as controls. Using CT images, we developed patient-specific three-dimensional surface hip models with the standing pelvic position as a reference. The loading scenario was based on single-leg stance. Four patterns of virtual PAO were performed in the models. First, the acetabular fragment was rotated laterally in the coronal plane so that the lateral center-edge angle was 30°; then, anterior rotation in the sagittal plane was added by 0°, 5°, 10°, and 15°. We developed finite-element models for each acetabular position and performed a nonlinear contact analysis to calculate the joint contact pressure of the acetabular cartilage. The normal range of the maximum joint contact pressure was calculated to be < 4.1 MPa using a receiver operating characteristic curve. A paired t-test or Wilcoxon signed rank test with Bonferroni correction