Powered by


                    Home  |  Forums  |  Humor  |  Advertising  |  Contact
   Ask a Doctor

   News via RSS







   Forum Archives





















   Primary Care






   Other Sections


   Research Tools

   Medical Tutorials

   Medical Software




Back to Orthopedics Articles

Friday 15th July, 2005


The risk of hip fracture rises exponentially with age, and may result from fragility of the femoral neck.



Certain types of exercise could protect against the steep increase in risk of hip fracture with age, suggests research in this week's issue of The Lancet.

The risk of hip fracture rises exponentially with age, and may result from fragility of the femoral neck. Dr Paul M Mayhew (University of Cambridge, UK) and colleagues used computed tomography to scan sections of femurs from 81 adults who died suddenly. They created three-dimensional reconstructions of the bone, then obtained a cross-sectional image of the mid-femoral neck. From these cross sections, they estimated the amount of stress that each region could tolerate before becoming unstable.

The thin cortical zone of the upper femoral neck became substantially thinner with age. In women, cortical thickness fell by 6?4% per decade, and critical stress by 13?2% per decade in the region most compressed by a sideways fall. Similar, but significantly smaller results were evident for men. This thinning reduced the amount of energy that the femur could absorb before buckling.

The authors suggest that the reason for this thinning is that bipedal walking does not transmit much load to this region. By contrast, the cortex of arboreal apes is almost symmetrically thick, since tree-climbing loads this region more than walking. As people age, their amount and variety of exercise is reduced, and walking becomes the main source of load on the femur.

The authors state: "Several popular forms of exercise also involve extension of the flexed femur under load (cycling, sculling, gymnastics, weights). Some should be investigated for their potential to protect, as part of our society's drive to increase physical activity for health."

In an accompanying Comment, Charles H Turner questions whether this new theory about buckling failure is too simplistic, but welcomes the potential for more detailed assessment of the regional pattern of bone loss and targeted interventions to strengthen underused bone regions.


Dr J Reeve, Box 157, Department of Medicine, Addenbrooke's Hospital, Cambridge CB2 2QQ, UK. T) +44 (0)1223 741617

Dr Charles H Turner, Departments of Biomedical Engineering and Orthopedic Surgery, Indiana University Purdue University Indianapolis, USA; T) +1 317 274 3226

advertisement.gif (61x7 -- 0 bytes)

Are you a doctor or a nurse?

Do you want to join the Doctors Lounge online medical community?

Participate in editorial activities (publish, peer review, edit) and give a helping hand to the largest online community of patients.

Click on the link below to see the requirements:

Doctors Lounge Membership Application


 advertisement.gif (61x7 -- 0 bytes)



We subscribe to the HONcode principles of the HON Foundation. Click to verify.
We subscribe to the HONcode principles. Verify here

Privacy Statement | Terms & Conditions | Editorial Board | About us
Copyright ? 2001-2012 DoctorsLounge?. All rights reserved.