INGENIEUR
Figure 3: 3D printing of the sensor pad
Engineering Designs
Previous studies done with VAG were performed
using single axis vibration sensors which would
use conventional analog sensors. These sensors
were easily disturbed by surrounding noise and
also had to rely on analog to digital conversion
(ADC) hardware which would also produce noise or
cause data loss. However, with the advancement
of technology and the development of MicroElectro-Mechanical Systems (MEMS), the sensors
have become highly sensitive with instant ADC
thanks to integrated circuit (IC) properties. Using
MEMS has also allowed
this project to capture
the knee vibration in
3-Axis.
To place the sensor
on the knee; the sensor
should not be in direct
contact with the skin. A
special flexible sensor
pad has been designed
using a 3D printer to
ensure comfor t for
the subject as well as
a stable area for the
sensor to capture the
data with high accuracy Figure 4: Sensor pad
(Figure 3). The sensor placed on the knee
pad then will be installed band
on the OA knee band to
be placed on the subject’s knee (Figure 4).
After the knee band is placed on the subject,
the subject will be asked to sit on a chair with the
knees at a 90o angle, and then to stand up and
sit down at specific times. The results will then be
processed by a microcontroller and saved in an SD
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card to be later used and analysed by a computer.
Patients selected were based on the medical
ethics rules and regulations and in collaboration
with University Malaya Medical Centre .
The 90o sit-stand motion is both easy for the
patients to perform as well as provides a wide
angle of motion for the sensor to monitor and
compare. During this motion the weight of the
body will cause the vibration to be produced at a
higher amplitude and help in detecting data much
more accurately. To control the speed of sitting
and standing, patients and subjects were asked
to perform the action by an animation displayed
on a screen which would signal when to stand up
and when to sit down.
For ease-of-use, portability and instant result
gathering, a device has been developed, patented
and trademark registered - OsteoKnee™ (Figure 5).
OsteoKnee™ is an early detection and progression
monitoring tool for osteoarthritis. OsteoKnee™
helps medical staff to observe and monitor the
condition and symptoms of OA in the patient. The
VAG sensor can be connected to the OsteoKnee™
and after the results have been processed with
a microcontroller, the results will be displayed on
the screen.
OsteoKnee™ has great potential for
commercialisation because there is currently no
diagnostic equipment available for OA assessment
based on knee sounds and knee pressure in the
market. OsteoKnee™ is low cost, non-invasive,
non-radioactive, portable, and easily accessible.
OsteoKnee™ can be very handy because it is a
standalone point-of-care medical device, which
can be easily obtained by clinics or even homes.
OsteoKnee™ features a new choice of diagnosis