title: Changes in chondrolabral mechanics, coverage, and congruency following peri-acetabular osteotomy for treatment of acetabular retroversion: A patient-specific finite element study.
abstract: Using a validated finite element (FE) protocol, we quantified cartilage and labrum mechanics, congruency, and femoral coverage in five male patients before and after they were treated for acetabular retroversion with peri-acetabular osteotomy (PAO). Three-dimensional models of bone, cartilage, and labrum were generated from computed tomography (CT) arthrography images, acquired before and after PAO. Walking, stair-ascent, stair-descent, and rising from a chair were simulated. Cartilage and labrum contact stress, contact area, and femoral coverage were calculated overall and regionally. Mean congruency (average of local congruency values for FE nodes in contact) and peak congruency (most incongruent node in contact) were calculated overall and regionally. Load supported by the labrum was represented as a raw change in the ratio of the applied force transferred through the labrum and percent change following surgery (calculated overall only). Considering all activities, following PAO, mean acetabular cartilage contact stress increased medially, superiorly, and posteriorly; peak stress increased medially and posteriorly. Peak labrum stresses decreased overall and superiorly. Acetabular contact area decreased overall and laterally, and increased medially. Labral contact area decreased overall, but not regionally. Load to the labrum decreased. Femoral head coverage increased overall, anterolaterally, and posterolaterally, but decreased anteromedially. Mean congruency indicated the hip became less congruent overall, anteriorly, and posteriorly; peak congruency indicated a less congruent joint posteriorly.
  
  
  
  Medialization of contact and reductions in labral loading following PAO may prevent osteoarthritis, but this procedure increases cartilage stresses, decreases contact area, and makes the hip less congruent, which may overload cartilage. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2567-2576, 2017.
authors.affiliation: Department of Orthopaedics, University of Utah, Salt Lake City, Utha 84108.
authors.forename: Spencer J
authors.initials: SJ
authors.lastname: Knight
authors.affiliation: Department of Orthopaedics, University of Utah, Salt Lake City, Utha 84108.|Department of Bioengineering, University of Utah, Salt Lake City, Utha 84112.
authors.forename: Christine L
authors.initials: CL
authors.lastname: Abraham
authors.affiliation: Department of Orthopaedics, University of Utah, Salt Lake City, Utha 84108.|Department of Bioengineering, University of Utah, Salt Lake City, Utha 84112.
authors.forename: Christopher L
authors.initials: CL
authors.lastname: Peters
authors.affiliation: Department of Orthopaedics, University of Utah, Salt Lake City, Utha 84108.|Department of Bioengineering, University of Utah, Salt Lake City, Utha 84112.|Scientific Computing and Imaging Institute, Salt Lake City, Utha 84112.
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Weiss
authors.affiliation: Department of Orthopaedics, University of Utah, Salt Lake City, Utha 84108.|Department of Bioengineering, University of Utah, Salt Lake City, Utha 84112.|Scientific Computing and Imaging Institute, Salt Lake City, Utha 84112.|Department of Physical Therapy, University of Utah, Salt Lake City, Utha 84108.
authors.forename: Andrew E
authors.initials: AE
authors.lastname: Anderson
mesh_terms: D000077:Acetabulum / Q000002:abnormalities* / Q000601:surgery*; D000293:Adolescent; D000328:Adult; D002358:Cartilage, Articular / Q000502:physiology*; D020342:Finite Element Analysis; D006621:Hip Joint / Q000502:physiology*; D006801:Humans; D008297:Male; D015207:Osteoarthritis, Hip / Q000517:prevention & control; D010027:Osteotomy; D055815:Young Adult
keywords: chondrolabral mechanics; finite element analysis; hip; morphology; retroversion