Health care meets aerospace diagnostics: Bio-ferrography

Aircraft mechanics have long assessed the wear on vital components by measuring the amount of metal shavings in lubricants. Now researchers at Tel Aviv University's Materials and Nanotechnologies Program are applying the same high-tech principles to evaluate the health of orthopedic joint implants.

Called ferrography when utilized by engineers and mechanics, the Tel Avive researchers call their approach "bio-ferrography," and propose that it may provide a better assessment of the condition of joint implants than the typical method, which relies on imaging technologies. Specifically, they assert that their approach is superior in its quantitative objectivity, sensitivity, and selectivity. Sounds good, how does it work?

As joint replacements or implants wear, they release tiny shards of metal, plastic or bone into the fluids surrounding the joint. By withdrawing some of those fluids using a needle, then examining it under a fun sounding instrument called a Bio-Ferrograph 2100 (manufactured by Guilfoyle, Inc., and pictured on the left), diagnosticians assess the condition of the implant based on the wear fragments they've collected.  Analysis involves counting fragments and measuring their dimensions to assess the extent of disease or wear, and establishing the shape and chemical composition of articles to establish exactly what they wore off from.

In tests of bio-ferrography to assess the effectiveness of an injected joint treatment, clinicians found that they were able to document treatment-related improvement in joint condition using the approach.

As the number of joint replacements grows, and lengthening active life expectancies increases demands for repeat-replacements, having an accurate way of diagnosing the condition of aging implants will become increasingly important. Having a way to do this without using imaging scans that are costly and carry radiation-related health risks is an added advantage.

Other cool health care advances on the cutting edge include:

• Home-based health tests with built in chemical timers, and


• Wound dressings that warn wearers of potential infection.