Type

Journal Article

Authors

T Clive Lee
David Taylor
Susan M Rackard
Fergal J O'Brien
Peter Mauer
Orlaith Brennan
Oran D Kennedy

Subjects

Medicine & Nursing

Topics
female etiology physiopathology complications animals injuries sheep domestic bone and bones ovariectomy compressive strength fluorescent dyes stress mechanical osteoporosis adverse effects metatarsal bones sheep physiology ovary haversian system fractures stress models animal

The behaviour of fatigue-induced microdamage in compact bone samples from control and ovariectomised sheep. (2008)

Abstract This study investigates the effect of microdamage on bone quality in osteoporosis using an ovariectomised (OVX) sheep model of osteoporosis. Thirty-four sheep were divided into an OVX group (n=16) and a control group (n=18). Fluorochromes were administered intravenously at 3 monthly intervals after surgery to label bone turnover. After sacrifice, beams were removed from the metatarsal and tested in three-point bending. Following failure, microcracks were identified and quantified in terms of region, location and interaction with osteons. Number of cycles to failure (Nf) was lower in the OVX group relative to controls by approximately 7%. Crack density (CrDn) was higher in the OVX group compared to controls. CrDn was 2.5 and 3.5 times greater in the compressive region compared to tensile in control and OVX bone respectively. Combined results from both groups showed that 91% of cracks remained in interstitial bone, approximately 8% of cracks penetrated unlabelled osteons and less than 1% penetrated into labelled osteons. All cases of labelled osteon penetration occurred in controls. Crack surface density (CrSDn), was 25% higher in the control group compared to OVX. It is known that crack behaviour on meeting microstructural features such as osteons will depend on crack length. We have shown that osteon age also affects crack propagation. Long cracks penetrated unlabelled osteons but not labelled ones. Some cracks in the control group did penetrate labelled osteons. This may be due the fact that control bone is more highly mineralized. CrSDn was increased by 25% in the control group compared to OVX. Further study of these fracture mechanisms will help determine the effect of microdamage on bone quality and how this contributes to bone fragility.
Collections Ireland -> Trinity College Dublin -> PubMed

Full list of authors on original publication

T Clive Lee, David Taylor, Susan M Rackard, Fergal J O'Brien, Peter Mauer, Orlaith Brennan, Oran D Kennedy

Experts in our system

1
T Clive Lee
Royal College of Surgeons in Ireland
Total Publications: 76
 
2
David Taylor
Trinity College Dublin
Total Publications: 75
 
3
Fergal J O'Brien
Royal College of Surgeons in Ireland
Total Publications: 265
 
4
Peter Mauer
Royal College of Surgeons in Ireland
 
5
Orlaith Brennan
Royal College of Surgeons in Ireland
Total Publications: 31
 
6
Oran D Kennedy
Royal College of Surgeons in Ireland
Total Publications: 24