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Radiographically Successful Periacetabular Osteotomy Does Not Achieve Optimal Contact Mechanics in Dysplastic Hips
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Radiographically Successful Periacetabular Osteotomy Does Not Achieve Optimal Contact Mechanics in Dysplastic Hips

Holly D. Aitken, Aspen Miller, Dominic J.L. Rivas, Marcus Tatum, Robert W. Westermann, Michael C. Willey and Jessica E. Goetz
medRxiv
Cold Spring Harbor Laboratory
04/01/2023
DOI: 10.1101/2022.05.26.22275634
url
https://doi.org/10.1016/j.clinbiomech.2023.105928View
Published (Version of record)This article has now been published in a journal and has been peer-reviewed by subject experts. This version may differ significantly from the preprint version. Access restricted to faculty, staff and students
url
https://doi.org/10.1101/2022.05.26.22275634View
Preprint (Author's original)This preprint has not been evaluated by subject experts through peer review. Preprints may undergo extensive changes and/or become peer-reviewed journal articles. Open Access

Abstract

ABSTRACTIntroductionOptimal correction of hip dysplasia deformity with periacetabular osteotomy (PAO) that minimizes elevated contact stresses may reduce osteoarthritis (OA) development.Questions/PurposesWe used a computational approach based on discrete element analysis (DEA) to determine (1) if computational optimization can identify patient-specific acetabular corrections that optimize joint contact mechanics, (2) whether a strictly mechanically optimal correction is clinically feasible, and (3) whether the contact mechanics of optimal corrections differ from those of surgically achieved corrections.MethodsPreoperative and postoperative hip models were created from CT scans of a retrospective cohort (n=20) who underwent PAO to treat hip dysplasia. A digitally extracted acetabular fragment was computationally rotated in two-degree increments of lateral and anterior coverage to simulate candidate PAO reorientations. DEA-computed contact stress for each candidate reorientation model was used to select a purely mechanically optimal reorientation that minimized chronic contact stress exposures above damaging thresholds and a clinically optimal reorientation that balanced reducing chronic exposures with achieving clinically realistic acetabular orientations. Radiographic coverage, contact area, peak/mean contact stress, and peak/mean cumulative exposure were compared between preoperative, mechanically optimal, clinically optimal, and surgically achieved acetabular orientations.ResultsComputationally optimal reorientations had significantly (p<0.001) more lateral and anterior coverage than surgically achieved PAO corrections. The mechanically/clinically optimal reorientations also had significantly more contact area (p<0.001/p=0.001) and significantly lower peak contact stress (p<0.001/p<0.001), mean contact stress (p<0.001/p=0.001), peak chronic exposure (p=0.001/p=0.003), and mean chronic exposure (p<0.001/p=0.001) than the surgically achieved corrections.ConclusionsThis computational approach identified patient-specific mechanically optimal and clinically optimal acetabular reorientations. Surgically achieved reorientations did not reduce contact stress exposure to the extent achieved with computed optimal reorientations. However, optimal orientations identified for many patients risk secondary femoroacetabular impingement. Identifying patient-specific corrections that balance optimizing mechanics with clinical reality is necessary to reduce the risk of OA progression after PAO.
Biophysics Orthopedics and Sports Medicine

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