Hanna researches bone solidity
As the years pass, we all get more brittle bones. They get thinner, less dense in structure and acquire a partially different composition. Finally, they snap as a result of a trip or fall which would have been completely harmless to a younger person. How quickly they deteriorate or how serious the problems become varies a lot, however. Women are more often affected by osteoporosis (brittleness in the bones) than men, but factors such as exercise, genes and nutrition also play a role.
A researcher in this field is Hanna Isaksson, assistant senior lecturer in biomechanics at the Division for Solid Mechanics. She works mainly on developing measurement methods and mathematical models for assessing bone quality.
“In a project supported by the Swedish Research Council, we are investigating the factors behind bone solidity. There are many such factors: the three-dimensional geometry, the bone structure at the detailed level, the relationship between the harder minerals and the softer but tougher collagens. We build templates and calculate bone strength with the finite element method”, explains Hanna Isaksson.
In a year or so the group hopes to have an indication as to whether they are on the right track. Two doctoral students are working on the project.
Osteoporosis is currently diagnosed with a standardised two-dimensional x-ray of the femoral neck and other bones, which is then compared to a limit value. The method is not very reliable. Several other factors enter into play but are not investigated. It is possible to make much better analyses using 3D x-rays but it is much more expensive and exposes patients to higher levels of radiation. The method of the Lund researchers is based on extracting additional and more reliable information from the standard method, using a statistical format template in three dimensions.
The aim is to achieve greater precision in the prediction of risk of fracture. In order to see whether this is successful, the results will be compared with patient data from a study in Malmö. The study has been ongoing for around ten years.
Osteoporosis entails both reduced bone mass and decreased bone quality. This can mean that it is more difficult for broken bones to heal and even more difficult to screw temporary or permanent prostheses onto the bones.
Currently, osteoporosis is mainly treated with bisphosphonates, which reduce resorption (degradation) and flatten out the downward curve of bone density. Balance? Vitamin D and calcium can be given as a preventative measure.
Another project deals with the fracture healing process and is taking place in cooperation with orthopedic specialists in Lund. They are testing new drugs that are to improve the bone’s ability to heal, among other things through experiments on rats. Diffraction and scattering experiments and infrared spectroscopy at Max Lab are some of the methods used by researchers to study the minerals in bone. They are examining the composition and structure of crystals. A doctoral student and a post-doc are working in this area using different methods.
“Experience shows that bone cells require the right amount of stimulation for healing to get underway. The patient cannot simply lie in bed”, points out Hanna.
Bone fracture can occur in all possible types of accidents where the body is subjected to excessive force. Otherwise, bone fractures usually occur in the wrist when people save themselves from a fall (low-energy fractures in advanced age). When people are perhaps no longer able to save themselves from a fall, it is usually the femoral neck that breaks. Vertebral compression (with a severe hump) is a further possible consequence of osteoporosis.
Text and photo: MATS NYGREN