Faculty Collaboration Database

A fracture risk assessment model of the femur in children with osteogenesis imperfecta (OI) during gait. Med Eng Phys 2009 Nov;31(9):1043-8

Date

08/18/2009

Pubmed ID

19683956

DOI

10.1016/j.medengphy.2009.06.010

Scopus ID

2-s2.0-70350380179 (requires institutional sign-in at Scopus site)   44 Citations

Abstract

Osteogenesis imperfecta (OI) is a heritable bone fragility disorder characterized by skeletal deformities and increased bone fragility. There is currently no established clinical method for quantifying fracture risk in OI patients. This study begins the development of a patient-specific model for femur fracture risk assessment and prediction based on individuals' gait analysis data, bone geometry from imaging and material properties from nanoindentation (Young's modulus=19 GPa, Poisson's ratio=0.3). Finite element models of the femur were developed to assess fracture risk of the femur in a pediatric patient with OI type I. Kinetic data from clinical gait analysis was used to prescribe loading conditions on the femoral head and condyles along with muscle forces on the bone's surface. von Mises stresses were analyzed against a fracture strength of 115 MPa. The patient with OI whose femur was modeled showed no risk of femoral fracture during normal gait. The highest stress levels occurred during the mid-stance and loading responses phases of gait. The location of high stress migrated throughout the femoral diaphysis across the gait cycle. Maximum femoral stress levels occurred during the gait cycle phases associated with the highest loading. The fracture risk (fracture strength/von Mises stress), however, was low. This study provides a relevant method for combining functional activity, material property and analytical methods to improve patient monitoring.

Author List

Fritz JM, Guan Y, Wang M, Smith PA, Harris GF

Authors

Jessica M. Fritz PhD Assistant Professor in the Orthopaedic Surgery department at Medical College of Wisconsin
Gerald Harris PhD Director in the Orthopaedic Research Engineering Center (OREC) department at Marquette University
Mei Wang PhD Associate Professor in the Orthopaedic Surgery department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Child
Elastic Modulus
Female
Femur
Finite Element Analysis
Fracture Healing
Fractures, Bone
Gait
Humans
Kinetics
Osteogenesis Imperfecta
Pressure
Risk Assessment
Stress, Mechanical
Weight-Bearing