Real-Time Performance Reports from an Instrumented Knee
From: Sensors Magazine - 04/2005 - page 12
By: Stephanie vL. Henkel

Most of us have heard from our knees after a tennis game, but how about a
knee that can deliver real-time data during various activities? Jerry Ward, a
retired aerospace engineer, is walking around on one today. This total knee
prosthesis, implanted at the Scripps Clinic Division of Orthopaedic Surgery,
is instrumented with force transducers, a microtransmitter, and an antenna
that transmits to an external receiver. Some of the components were made by
MicroStrain Inc., a developer of wireless microsensors. The prosthesis will
allow real-time measurements on the distribution of forces to the implant and
load-carrying capabilities of the bone as Ward walks, climbs stairs, and
exercises. The top of the implant is similar to a standard model, with a
typical femoral component and polyethylene articular surface. The lower
component, made of titanium, is customized to allow measurement of loads
across the knee. Four metal posts separate the top and bottom plates; strain
sensors under the posts monitor changes in the metal as Ward moves. A
removable coil around the knee activates the system, then sends data to a
computer for conversion into loads in pounds at each of the four posts. 

Contact:
Darryl D’Lima, MD
Shiley Center for Orthopaedic Research and Education
Scripps Clinic
La Jolla, CA
858/332-0142
dd’lima@scrippsclinic.com

Links:
Shiley Center for Orthopaedic Research and Education at Scripps Clinic
http://www.scrippsclinic.com/Specialties/score.cfm

Hoping for a Knee-Jerk Reaction
http://wired-vig.wired.com/news/print/0,1294,62716,00.html

Research E-Knee provides data for future joint replacements
http://www.aaos.org/wordhtml/2005news/thurs/a24-13.htm

Electronic Knee Implant
Researchers at the Shiley Center for Orthopaedic Research and Education have
developed an innovative electronic knee prosthesis that has the ability to
directly measure forces that occur across the knee as someone moves. This one
of a kind implant can measure, in real time, the forces the knee is subjected
to when a person walks, climbs stairs, or exercises. Once implanted, this
device will provide researchers and industry with valuable new information
that will allow future improvements in implant design, rehabilitation
programs, and assistive devices. 

From: http://www.scrippsclinic.com/Specialties/clinres.cfm