Shriners Gait Analysis

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http://www.shrinershq.org/WhatsNewArch/Archives00/motionanalysis12-00.html

There is a great deal of science involved in how a person moves. For centuries,

scientists have studied motion and developed countless theories about why people

move the way they do. Most of us take the ability to move for granted, but for

many of the children who come to Shriners Hospitals for Children, simple body

movements can be challenging.

Since Shriners Hospitals' patients often suffer from multiple conditions that

can make the treatment process more complex, motion analysis is an important

diagnostic tool that can lead to more successful medical outcomes.

Earlier this year, the Shriners Hospital in Erie , Pa., opened the newest motion

analysis lab (MAL) which uses special equipment and computer programs to better

understand how children use muscles and joints to move. This functional movement

analysis conducted by the MAL's specially trained staff results in information

regarding muscle activity, joint movement and forces affecting the patient

during various activities. Walking, running or even grasping a cup can all be

studied, according to Buczek, Ph.D., the lab's director.

The new Erie Hospital lab is one of the most technologically advanced facilities

of its kind. What makes the Erie MAL different is the floor design utilizing

moveable force plates that can be adjusted to the natural step of the child. The

plates sit on a special epoxy foundation, level to 4/1000ths of an inch. Air

bearings can then be used to easily slide the 300-pound plates to their desired

positions. Cecilia Concha, MAL engineer, indicated that this increases the

probability that forces between the ground and foot will be available for

analysis without unduly fatiguing patients.

A typical gait analysis uses Vicon Clinical Manager (stick figures) to assess

rotational biomechanics at the hip, knees and ankles. Emerging technology at the

Erie Hospital will use NIH MOVE3D (wire-frame figures), as seen in the above

diagram, to more accurately assess rotations and sliding at all major body

joints.

" Data collected from the force plates are essential building blocks for

calculating both twisting and sliding forces within the joints, " Buczek said.

" These, in turn, help our MAL staff distinguish between root causes that can be

addressed by physicians, and compensations that will likely resolve when the

root causes are treated. "

The force plate data is not the only source of information being collected

during a gait analysis. Cooney, MAL physical therapist, can use surface or

fine-wire electromyography (EMG) to collect data on electrical impulses being

emitted by the child's muscles. The lab's six-camera infrared Vicon system

accurately quantifies the child's movement patterns and synchronizes this

information with force plate and EMG data. Video cameras with split-screen

technology provide front and side views of the patient for qualitative analysis,

creating a direct link to common clinical evaluations.

Buczek reviews some of the data collected on a varus foot study that was done on

a patient.

" This is all state-of-the-art technology, " Buczek noted. " The accuracy of the

data we collect, stored in a MAL database developed by Dylewski, MAL

clerk, makes it possible for the physicians and staff to develop the best

possible treatment options for our patients. "

While the clinical data currently being collected on patients is extremely

accurate, Buczek pointed out that improvements in biomechanical modeling are

needed to better answer some common referral questions and to address

fundamental research questions about how we move. In fact, the Erie MAL staff is

embarking on some new and exciting research that can ultimately enhance patient

care.

" A typical motion analysis requires tens of thousands of calculations, and for

this reason, the field of biomechanics is driven by computer software, " Buczek

emphasized. " Although the biomechanical model we currently use to analyze gait

data is very good, there is another model that could potentially provide even

better data. "

This other model accounts for three rotations and three directions for sliding

within each joint, and therefore uses what is known as a six-degree-of-freedom

(6 DOF) approach. Scientific software called MOVE3D was developed about 10 years

ago at the National Institute of Health, and although it uses a 6 DOF model, it

remains somewhat " user unfriendly " and has not seen widespread clinical use.

Currently, C-Motion, Inc., is executing a technology transfer to commercialize

software that encompasses MOVE3D and makes it easier to use in clinical

applications like motion analysis. The Erie lab is a pilot site for this revised

software.

Six-year-old iel of Detroit is one of many Erie Hospital patients who has

undergone testing in the hospital's new motion analysis lab. The data collected

is used to help develop treatment options for the youngster.

" This is very exciting for us because it opens many doors in the areas of

research and education, as well as patient care, " Buczek said. For example,

Buczek believes the 6 DOF approach will improve his staff's ability to identify

twisting of bones in the thigh and lower leg, better guiding orthopaedists who

are considering derotation osteotomies.

There remain fundamental questions about how humans generate forces to move

forward in walking, and a basic research project will use 6 DOF analyses to

better understand the roles of gravity, posture and active muscle powers. Dr.

O. , chief of staff at the Erie Hospital and a valuable contributor

to instrumented gait evaluations, explained that the 6 DOF model can be applied

to clinical research examining the causes of crouching in cerebral palsy

patients, or the causes of varus positioning (turning in) of the foot. He added

that this type of advanced data analysis offers outstanding education

opportunities for physicians, residents, physical therapy students, engineering

students and others.

The use of the most sophisticated equipment available, combined with advanced

computer software and enhanced research programs, places the Erie MAL on the

cutting edge of the science of motion analysis. And in the ever-changing

scientific world, the best may be yet to come.

More information on Shriners Hospitals' gait labs.

April 27, 2001