Gait Analysis

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Nov 13, 2013 (3 years and 11 months ago)

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Gait Analysis:
Techniques and
Recognition of

Abnormal Gait


Fabian E. Pollo, Ph.D.

April 30, 2007

Gait Analysis: Techniques and
Recognition of Abnormal Gait


April 30, 2007

Gait analysis in
modern terms
implies that
some type of
quantification
will take place.



Gait Analysis: Techniques and
Recognition of Abnormal Gait


April 30, 2007

1. Temporal / Spatial


velocity, cadence, step


length, etc.


2. Kinematics
-

the movement of the body in


space without any reference to forces.


3. Kinetics
-

the forces involved in producing


these movements.


4. Dynamic Electromyography
-

the study of


muscular activity patterns during walking.

Gait analysis involves the measurement of:

Gait Analysis: Techniques and
Recognition of Abnormal Gait


April 30, 2007

Temporal
-
Spatial Parameters

1.
Stop watch and marks
on the floor


2.
Gait Pressure Mat

Gait Pressure Mat

Gait Analysis: Techniques and
Recognition of Abnormal Gait


April 30, 2007

Gait Analysis: Techniques and
Recognition of Abnormal Gait


April 30, 2007

Kinematics

can be recorded using a
variety of systems and methodologies

Passive Marker Systems

use
reflective markers and multiple
cameras (typically 6 to 8 cameras
simultaneously). The cameras send
out infra red light signals and detect
the reflection from the markers
placed on the body. Based on the
reflected signals from at least 2
cameras
-

triangulation of the
marker in space is possible.

Gait Analysis: Techniques and
Recognition of Abnormal Gait


April 30, 2007

Kinematics

can be recorded using a
variety of systems and methodologies

Active Marker Systems

are similar
to the passive marker system but
use "active" markers. The markers
are triggered to illuminate. This
signal is used to triangulate the
location of the marker. The
advantage is that individual markers
work at predefined frequencies and
therefore, have their own "identity".

Gait Analysis: Techniques and
Recognition of Abnormal Gait


April 30, 2007

Kinematics

can be recorded using a
variety of systems and methodologies

Electromagnetic Systems

track the
position (X, Y, and Z Cartesian
coordinates) and orientation
(azimuth, elevation, and roll) of
small sensors attached to various
segments of the body as they move
through space.

Gait Analysis: Techniques and
Recognition of Abnormal Gait


April 30, 2007


Vicon Motion Analysis System


Twelve MX
-
40 Cameras


4


Megapixel Resolution


5 Hz


2,000 Hz


Passive Marker System


Near Infra
-
Red Ring LEDs


Camera/Computer

Baylor Motion & Sports Performance Center

Force Platforms

Gait Analysis: Techniques and
Recognition of Abnormal Gait


April 30, 2007

Camera Positioning (Think Volume)

Gait Analysis: Techniques and
Recognition of Abnormal Gait


April 30, 2007

X

Y

Z

L
-

Frame


designates lab origin and orientation (Global Coordinate System)


Calibration: L
-
Frame

Gait Analysis: Techniques and
Recognition of Abnormal Gait


April 30, 2007

Wand


defines camera positions in relation to each other in 3D space and
corrects for any lens distortion



Calibration: Wand

Gait Analysis: Techniques and
Recognition of Abnormal Gait


April 30, 2007

Various Markers Sets and
Gait Models dependent on
application

Gait Analysis: Techniques and
Recognition of Abnormal Gait


April 30, 2007

Direct Linear Transformation

Camera 1

Camera 2

Camera 3…………

Camera 12

3D Image

DLT

Take all

12 Raw Video
Camera Views

Identified Markers

3D Image

Virtual Hip Joint Centers

Gait Analysis: Techniques and
Recognition of Abnormal Gait


April 30, 2007

Kinematics

Gait Analysis: Techniques and
Recognition of Abnormal Gait


April 30, 2007

Force Platform

The reaction force
produced by the ground is
called the Ground
Reaction Force (GRF),
which is basically the
reaction to the force the
body exerts on the
ground.

Kinetics

Gait Analysis: Techniques and
Recognition of Abnormal Gait


April 30, 2007

Use

Inverse Dynamics

to

compute

Joint Forces,
Joint Torques
(Moments) and Joint
Power.

Kinetics

Gait Analysis: Techniques and
Recognition of Abnormal Gait


April 30, 2007

Electromyography

25 Gauge Needle

0.051mm, insulated, hooked wires

Gait Analysis: Techniques and
Recognition of Abnormal Gait


April 30, 2007

Raw EMG Signal

Rectified EMG Signal

Enveloped EMG Signal

Processing

Gait Analysis: Techniques and
Recognition of Abnormal Gait


April 30, 2007

Recognition of Abnormal Gait


Question is not whether a gait pattern is abnormal


what is primary cause.



Requires formal gait analysis



Many primary causes are fairly easy to diagnose
(i.e. bunions and peroneal nerve dysfunction)



Many secondary causes that are not so clear
(chronic ligament tears and osteoarthritis)

Gait Analysis: Techniques and
Recognition of Abnormal Gait


April 30, 2007

1.

Mild Cerebral Palsy


2.
Traumatic Brain Injury


3.
Medial Compartment Osteoarthritis

Examples

Recognition of Abnormal Gait

Gait Analysis: Techniques and
Recognition of Abnormal Gait


April 30, 2007

Cerebral Palsy



9 year old girl with hemiplegia




Equinovarus of her right foot


(inverted hindfoot and plantarflexed)




Caused by overpull of the tibialis


posterior and/or anterior tibialis


Tendons





Gait Analysis: Techniques and
Recognition of Abnormal Gait


April 30, 2007

Surgical Options

Split anterior tibialis and transfer

tendon to cuboid.

Split posterior tibial tendon and
transferred laterally to peroneus
brevis tendon

Gait Analysis: Techniques and
Recognition of Abnormal Gait


April 30, 2007

Use of Gait Analysis



Determine if the anterior tibialis and/or


posterior tibialis was contributing to her


deformity.




Document her movement pattern for


comparison after surgery.




Gait Analysis: Techniques and
Recognition of Abnormal Gait


April 30, 2007

Traumatic Brain Injury



45 year male suffered TBI in car


accident in 1983




Having Left Knee Pain




Gait Evaluation





Gait Analysis: Techniques and
Recognition of Abnormal Gait


April 30, 2007

Knee Osteoarthritis



51 year old women with medial


compartment OA of left knee




Evaluation for OA unloader


brace prior to possible High


Tibial Osteotomy





Gait Analysis: Techniques and
Recognition of Abnormal Gait


April 30, 2007

Knee Osteoarthritis


Knee OA results from local
mechanical factors within the
context of systemic susceptibility


Hip
-
knee
-
ankle alignment
significantly influences

load distribution at the knee and
disease progression



Medial compartment more often
affected

Gait Analysis: Techniques and
Recognition of Abnormal Gait


April 30, 2007



Vertical GRF



Muscular Forces



Reaction force from


external moment

Knee Loading

Gait Analysis: Techniques and
Recognition of Abnormal Gait


April 30, 2007

Knee Osteoarthritis



Unloader Bracing attempts to


reduce that “Varus” load.





Gait Analysis: Techniques and
Recognition of Abnormal Gait


April 30, 2007

Benefits of Gait Analysis


Aids in surgical planning


Assessing the efficacy of surgical intervention


Bracing issues and medication efficacy can be
addressed using gait analysis techniques


Evaluation of the rate of deterioration in
progressive disorders that affect gait can also
aid in understanding a patient's abilities and
directing care


Quantification for clinical and research

THANK YOU

April 30, 2007