Microfracture are tiny fractures in a bone caused when the force applied to a bone exceeds the strength of that bone. This can be achieved through strenuous activities such as running, dance, military training or gymnastics. The result is weakening of the bone which can result in a normal, complete bone breakage or macrofracture. When microfractures occur, the rate of bone formation by osteoblasts is outpaced by the normal osteoclastic bone destruction, as the osteoblasts are now having to form bone to fill cracks as well as their normal bone formation. Hence the bone is weakened and more susceptible to fracture under strain. However if the bone is given rest, osteoblastic activity can catch up and completely repair the bone.
For elite athletes it is very important to know when they need to take a break, if they are to avoid macrofractures and the long time periods in which they cannot train or compete which are associated with this. Although pain is often associated with microfracture, diagnosis can often be hard. There are already some methods of examining bones for microfractures, but off them had its disadvantages.
Currently the use of Raman spectroscopy is being examined. In Raman spectroscopy
a monochromatic beam of electromagnetic radiation if fired at the substance
being studied. Of the photons in this beam one in 10 million photons will strike
a molecule and give up some of their energy to emerge with a lower frequency.
Other photons will strike molecules and end up with a higher frequency by gaining
energy from the molecule. This change in frequency between the starting photons
and those produced depends on the molecule being studied. The change in frequency
between the incident photons and those produced differs between healthy bone
and bone containing microcracks or which has diffuse damage (lots of microcracks
that are too small to be individually identified). The signals for Raman spectrum
run on damaged bone are also broader. This indicates an amorphous or unstable