Abstract
BackgroundImpingement resulting in soft tissue damage has been observed in hips with abnormal morphologies. Geometric parameterisation can be used to automatically generate a range of bone geometries for use in computational models, including femurs with cam deformity on the femoral neck. MethodsThis study verified patient-specific parametric finite element models of 20 patients with cam deformity (10 female, 10 male) through comparison to their patient-specific segmentation-based equivalents. The parameterisation system was then used to generate further models with parametrically defined geometry to investigate morphological changes in both the femur and acetabulum and their effects on impingement. FindingsSimilar findings were observed between segmentation-based and parametric models when assessing soft tissue strains under impingement conditions, resulting from high flexion and internal rotations. Parametric models with cam morphology demonstrated that clinically used alpha angles should not be relied on for estimating impingement severity since planar views do not capture the full three-dimensional geometry of the joint. Furthermore, the parametric approach allowed study of labral shape changes, indicating higher strains can result from bony overcoverage. InterpretationThe position of cams, as well as their size, can affect the level of soft tissue strain occurring in the hip. This highlights the importance of reporting the full details of three-dimensional geometry used when developing computational models of the hip joint and suggests that it could be beneficial to stratify the patient population when considering treatment options, since certain morphologies may be at greater risk of elevated soft tissue strain.
Highlights
Abnormal bone morphology in the hip is associated with femoroacetabular impingement (FAI), in which repeated contact between the proximal femur and the acetabular rim can result in pain and intraarticular damage (Ganz et al, 2003)
It is important that parametric models are compared with segmented patientspecific models in order to understand the effects of smoothing out local undulations in subject-specific articular geometries
This study has quantified the effects of using parametric geometries when investigating femoroacetabular impingement, by comparison with a gold standard segmentation approach
Summary
Abnormal bone morphology in the hip is associated with femoroacetabular impingement (FAI), in which repeated contact between the proximal femur and the acetabular rim can result in pain and intraarticular damage (Ganz et al, 2003). In order to investigate the effects of bone morphology on tissue strains computationally, it is useful to be able to automatically generate multiple geometries representative of the population variation. This can be achieved using a parametric approach to finite element models of the hip (Hua et al, 2015; Chegini et al, 2009). Interpretation: The position of cams, as well as their size, can affect the level of soft tissue strain occurring in the hip This highlights the importance of reporting the full details of three-dimensional geometry used when developing computational models of the hip joint and suggests that it could be beneficial to stratify the patient population when considering treatment options, since certain morphologies may be at greater risk of elevated soft tissue strain
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
