Comparison of Acetabular Morphology Changes After Pediatric Pelvic Osteotomies Using Patient-Specific 3-D Models

Abstract

Background: Surgical management to improve hip joint morphology in immature patients with acetabular dysplasia includes Pemberton, Dega, San Diego, and Salter acetabular osteotomies. This study evaluates acetabular morphology between these osteotomies using patient-specific 3-D printing technology. Methods: Preoperative computed tomography scans (CTs) from patients with acetabular dysplasia were rendered into 3-D printable formats. Quadruplicate pelvis models for each patient received Pemberton, Dega, San Diego, and Salter osteotomies. CTs were obtained of each model before and after osteotomy. Acetabular volume and regional coverage angles were computed and compared before and after each osteotomy. Results: Fourteen hips (14 patients) were included; 1 male, 13 female; age 5.4±1.3 years (3.9-7.5 years). Acetabular volume decreased following each osteotomy (Pemberton by 14%, Dega by 19%, San Diego by 19%, and Salter by 6%), with smaller volume reduction for Salter than the others (p<0.05). Volume change was similar between Pemberton, Dega, and San Diego (p=0.32). Pemberton increased coverage in Superior and Anterior regions, Dega increased coverage in Superior, Superior-Anterior, and Anterior regions, San Diego increased coverage in Posterior, Superior-Posterior, and Superior regions, and Salter increased coverage in Superior region (p<0.05). Conclusions: Acetabular volume changes found in this study support the convention that redirectional osteotomies such as Salter are more volume neutral than incomplete osteotomies such as Pemberton, Dega, and San Diego. However, even the Salter decreased acetabular volume. This study re-demonstrated that each osteotomy studied changes acetabular coverage in different regions. Based on this, a surgeon’s osteotomy decision should be based on the dysplastic acetabulum morphology.

The Anterior Modified San Diego Acetabuloplasty Does Not Increase Superior-Anterior Coverage in Patient-Specific 3D-Printed Models

“…Similar to previously published studies, we found that the SDA and mSDA mainly affected their change in acetabular morphology posteriorly, while Pemberton primarily changed the anterior coverage. 14,15 We did not find that placement of the graft in a more anterior position for the SDA changed the coverage of the graft, with both still causing significantly more posterior coverage. This is a departure from the previous studies.…”

“…Understanding the morphology of the dysplastic acetabulum before surgical intervention is important for successful treatment, and 3D CT scans and models are great tools to help surgeons precisely identify deficiencies within the acetabulum 19–21 . In addition, 3D modeling is a powerful tool that can be used to comparatively study the changes after different pelvic osteotomies 14,15 and the current study further demonstrates this utility. Similar to previously published studies, we found that the SDA and mSDA mainly affected their change in acetabular morphology posteriorly, while Pemberton primarily changed the anterior coverage 14,15 .…”

“…Comparative studies utilizing patient-specific 3dimensional (3D) pelvic models have been used to investigate the changes in acetabular coverage after common pelvic osteotomies (San Diego, Pemberton, Dega, Salter, etc.). [14][15][16] Using a 3D-printed model, it is possible to evaluate the quantitative changes in acetabular coverage after different pelvic osteotomies in the same patientspecific models. Previous studies 14,15 have utilized the plastic printing material acrylonitrile butadiene styrene since it is easily imaged by computed tomography (CT) for quantitative image analysis, it has a similar resistance to bone when cut with an oscillating saw, 17 and it can be used to recreate rigid or flexible composites that can be used to simulate the varied osseous and cartilaginous structures of the developing hip.…”

“…[14][15][16] Using a 3D-printed model, it is possible to evaluate the quantitative changes in acetabular coverage after different pelvic osteotomies in the same patientspecific models. Previous studies 14,15 have utilized the plastic printing material acrylonitrile butadiene styrene since it is easily imaged by computed tomography (CT) for quantitative image analysis, it has a similar resistance to bone when cut with an oscillating saw, 17 and it can be used to recreate rigid or flexible composites that can be used to simulate the varied osseous and cartilaginous structures of the developing hip. The aim of the current study is to quantify the morphologic changes in acetabular coverage after SDA, mSDA, and Pemberton acetabuloplasty (PA) on patient-specific 3D-printed models.…”

“…Comparative studies utilizing patient-specific 3-dimensional (3D) pelvic models have been used to investigate the changes in acetabular coverage after common pelvic osteotomies (San Diego, Pemberton, Dega, Salter, etc.) 14–16 . Using a 3D-printed model, it is possible to evaluate the quantitative changes in acetabular coverage after different pelvic osteotomies in the same patient-specific models.…”