Capsular mechanics after periacetabular osteotomy for hip dysplasia

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Title: Capsular mechanics after periacetabular osteotomy for hip dysplasia
Authors: Ng, KC
Bankes, M
El Daou, H
Beaule, P
Cobb, J
Jeffers, J
Item Type: Journal Article
Abstract: Background: Hip dysplasia is characterized by insufficient acetabular coverage around the femoral head, which leads to instability, pain, and injury. Periacetabular osteotomy (PAO) aims to restore acetabular coverage and function, but its effects on capsular mechanics and joint stability are still unclear. The purpose of this study was to examine the effects of PAO on capsular mechanics and joint range of motion in dysplastic hips. Methods: Twelve cadaveric dysplastic hips (denuded to bone and capsule) were mounted onto a robotic tester and tested in multiple positions: (1) full extension, (2) neutral 0°, (3) flexion of 30°, (4) flexion of 60°, and (5) flexion of 90°. In each position, the hips underwent internal and external rotation, abduction, and adduction using 5 Nm of torque. Each hip then underwent PAO to reorient the acetabular fragment, preserving the capsular ligaments, and was retested. Results: The PAO reduced internal rotation in flexion of 90° (∆IR = –5°; p = 0.003), and increased external rotation in flexion of 60° (∆ER = +7°; p = 0.001) and flexion of 90° (∆ER = +11°; p = 0.001). The PAO also reduced abduction in extension (∆ABD = –10°; p = 0.002), neutral 0° (∆ABD = –7°; p = 0.001), and flexion of 30° (∆ABD = –8°; p = 0.001), but increased adduction in neutral 0° (∆ADD = +9°; p = 0.001), flexion of 30° (∆ADD = +11°; p = 0.002), and flexion of 60° (∆ADD = +11°; p = 0.003). Conclusions: PAO caused reductions in hip abduction and internal rotation but greater increases in hip adduction and external rotation. The osseous acetabular structure and capsule both play a role in the balance between joint mobility and stability after PAO.
Issue Date: 1-Jun-2022
Date of Acceptance: 18-Jan-2022
DOI: 10.2106/JBJS.21.00405
ISSN: 0021-9355
Publisher: Lippincott, Williams & Wilkins
Start Page: 1015
End Page: 1023
Journal / Book Title: The Journal of Bone and Joint Surgery
Volume: 104
Issue: 11
Copyright Statement: © 2022 by The Journal of Bone and Joint Surgery, Incorporated.
Sponsor/Funder: Engineering & Physical Science Research Council (EPSRC)
Engineering & Physical Science Research Council (E
National Institute for Health Research
Funder's Grant Number: EP/K027549/1
Keywords: Acetabulum
Hip Joint
Hip Dislocation, Congenital
Hip Dislocation
Range of Motion, Articular
Biomechanical Phenomena
0903 Biomedical Engineering
1103 Clinical Sciences
Publication Status: Published
Embargo Date: 2023-02-07
Online Publication Date: 2022-02-08
Appears in Collections:Mechanical Engineering
Department of Surgery and Cancer
Faculty of Medicine
Faculty of Engineering