Protrusio acetabuli: joint loading with severe pincer impingement and its theoretical implications for surgical therapy
Publisher DOI
PubMed ID
25297821
Abstract
Severe pincer impingement (acetabular protrusio) is an established cause of hip pain and osteoarthritis. The proposed underlying pathomechanism is a dynamic pathological contact of the prominent acetabular rim with the femoral head-neck junction. However, this cannot explain the classically described medial osteoarthritis in these hips. We therefore asked: (1) Does an overload exist in the medial aspect of the protrusio joint? and (2) What is the influence of three contemporary joint-preserving procedures on load distribution in protrusio hips? In vivo force and motion data for walking and standing to sitting were applied to six 3D finite element models (normal, dysplasia, protrusio, acetabular rim trimming, acetabular reorientation, and combined reorientation/rim trimming). Compared with dysplasia, the protrusio joint resulted in opposite patterns of von Mises stress and contact pressure during walking. In protrusio hips, we found an overload at the medial margin of the lunate surface (54% higher than normal). Isolated rim trimming further increased the medial overload (up to 28% higher than protrusio), whereas acetabular reorientation with/without rim trimming reduced stresses by up to 25%. Our results can be used as an adjunct for surgical decision making in the treatment of acetabular protrusio.
Date Issued
2015-01
Publication Type
Article
Subject(s)
Subjects
biomechanics
•
finite element
•
hip joint
•
pincer impingement
•
protrusio acetabuli
Language(s)
en
Additional Credits
Journal
Journal of orthopaedic research
Publisher
Wiley
ISSN
0736-0266
Access(Rights)
restricted