1. FEDERAL UNIVERSITY OF
TECHNOLOGY AKURE
SCHOOL OF HEALTH AND HEALTH TECHNOLOGY
A SEMINAR REPORT ON
GIAT MECHANICS IN LOWER LIMB
AMPUTATION– DO THE USE OF
PROSTHESIS IMPROVE AMPUTEE GAIT?
AROWOLO AYOMIDE. P
BIM/15/3168
BIOMEDICAL TECHNOLOGY
2. INTRODUCTION
DEFINITIONS
• Amputation: The surgical ablation of body part
through one or two bone(s).
• Disarticulation: The surgical ablation of body part
through joint.
• Lower Limb: For anatomists, this consists of the
thigh (the upper leg), the leg (the lower leg), and the
foot.
• The thigh consists of a single bone, the femur.
• The leg consists of two long bones, the tibia and
fibula.
3. INTRODUCTION CONTD.
• Gait mechanics: This is the systematic study of human mobility,
utilizing the eye and the brain of observers, enhanced with
technology for monitoring body motions and mechanics linked to the
functioning of the musculoskeletal system (Rodriguez, et, al. 2019).
• Walking is not difficult for healthy people, but it can be exhausting
and challenging for those with gait disorders including hemiparesis,
spinal cord injury, or Amputation (Harandi VJ, et al. 2020).
4. INTRODUCTION CONT.
• The human gait is described as a bipedal, biphasic forward propulsion of
the center of gravity (COG) of the human, in which there are alternate
sinuous movement of different segment of the body with least expenditure
of energy (Normal gait)
• Bipedal Ambulation has a complex interaction between the neuromotor,
muscular, and skeletal systems.
• To attain forward movement and stability, all humans must follow a similar
Gait procedure. Individual structural differences, on the other hand,
contribute to the peculiarities of each individual's dynamic walking
pattern.
• Walking is not difficult for healthy people, but it can be exhausting and
challenging for those with gait disorders including hemiparesis, spinal cord
injury, or Amputation.
5. GAIT CYCLE
• During locomotion, a gait is a pattern of limb motions.
• Normal Gait: A Series of rhythmical , alternating movements of the trunk &
limbs which result in the forward progression of the center of gravity (COG)
(Esquenazi A, 2014).
• Gait cycle is the period of time from one heel strike to the next heel strike of the
same limb.
• The gait cycle consists of two phases…
1. STANCE PHASE
2. SWING PHASE
The graphical representation of the step sequence of a normal gait
7. STANCE PHASE
•This begins with the heel of the foot striking the
ground i.e. the moment when the heel begins to touch
the ground but the toes do not yet touch and in the
midstance phase we can see settlement of the foot at
the lateral border. during the change from mid stance
to toe off stance and ends when the toe of the same
leg lifts off.
•Constitutes approximately 60% of the gait cycle.
8. SWING PHASE
• The swing phase begins when the stance phase ends. This phase is
between the toe off phase and the heel strike phase.
• In the swing phase we can recognize two extra phases, acceleration
and deceleration
• In the acceleration phase, the swing leg makes an accelerated forward
movement with the goal of propelling the body weight forward.
• The deceleration phase breaks the velocity of this forward body
movement in order to place your foot down with control
11. GAIT TERMINOLOGIES
• Time and distances are two basic parameters of motion.
1. Time (temporal) variables
i. Single limb support time
ii. Double support time
iii. Cadence
iv. Speed
2. Distance (spatial) variables
i. Stride length
ii. Step length
iii. Degree of toe out
12. Time (Temporal) variables
• Single limb support time: The amount of time that spent during the
period when only one extremity is on the supporting surface leg of a
gait cycle.
• Double limb support time: The amount of the time spent with both
feet on the ground during one gait cycle.
• The time of double support may be increased in elder patients and in
those having balance disorders
• The time of double support decreases when speed of walking
increases.
14. Distance (spatial) variables
i. Stride length : The Distance between successive point of heel
contact of the same foot
ii. Step length : The Distance between corresponding successive point
of heel contact of the opposite feet.
iii. Degree of toe out : It represents the angle of foot placement and
may be found by measuring the angle formed by each foot’s line of
progression and a line intersecting the center of heel and second
toe.
• The angle for men is about 7 degree. The degree of toe out decreases
as the speed of walking increases in normal men.
15. GAIT INFLUENCE ON AMPUTEE’S
• The gait influence on amputee can be determined by the dynamic
walking model
• The dynamic walking model was an acceptable variant of the six
determinant gait theory, which has the effective hypothesis of
minimizing metabolic energy expenditure on the use of prosthesis for
amputees, and minimizing the amount that the body's center of
gravity is displaced from the line of progression.
• This is the main mechanism for reducing the muscular effort of
walking, and thus, conserving energy.
16. DETERMINANTS OF GAIT ON AMPUTEES
• Six optimizations used to minimize excursion of Centre of gravity
(cog) in vertical & horizontal planes
• Reduce significantly energy consumption of ambulation
• The six determinants are;
Lateral pelvis tilt
Knee flexion
Knee, ankle and foot interactions
Forward and backward rotation of pelvis
Physiological valgus of knee
17. GAIT DEVIATION’S ON PROSTHESIS USER'S
• An amputee's rehabilitation procedure requires a thorough understanding of the
source and predicted biomechanical impact of the cause and deviation of the
impulse that affects prosthesis alignment or components.
• One of the most common gait deviations observed in amputees with transfemoral
amputations is knee flexion during the stance phase; it may result in limb
instability, loss of standing balance, and falls.
• Patients are unable to control the knee flexion moment during the stance phase
and become fearful of weight bearing on the prosthetic side. This situation results
in an inefficient gait pattern that requires the use of upper-limb support or
shortening of the step length. In most cases, prosthetic alignment adjustments to
improve knee stability may suffice, but occasionally the use of a mechanical knee
brake may be required
18. A Gait deviation on transtibial amputee
Depiction of the effect of appropriate heel height (right) and higher heel on the prosthetic alignment
of a person with transtibial amputation using the force-line visualization system.
19. CASE STUDY
• A total of 40 age-matched individuals participated in this study: 12 unilateral
transtibial amputees (TTA), 13 unilateral transfemoral amputees (TFA), and 15
healthy control individuals (CT). Lower limb amputations were due to trauma in
all cases .17 amputees had under-gone amputation of the left limb and 8
amputees had undergone amputation of the right limb.
• All amputees were experienced walkers, wearing their prosthesis daily, without
any musculoskeletal impairment in the intact side. However, eleven of them
reported to have experienced falls over the past.
• Using 10 infrared cameras operating at 100 samples (Vicon nexus, oxford
metrics, oxford, UK). For all participants, reflective markers were attached to the
both lateral malleoli’s, the heels, the head of the second and fifth metatarsals, and
the spinous process of T1 vertebrae.
20. CASE STUDY CONT.
• The observation was that as inclination increases, non-linear gait stability
(trunk local dynamic stability) declines and linear variability (trunk
variability and spatiotemporal parameters) decreases on amputees.
• Following considerable changes in gait spatiotemporal characteristics,
local dynamic stability deteriorated and linear variability increased
simultaneously with incline planes on Amputee’s.
• These alterations were substantially larger in amputees, and the level of
amputation had a major impact on the results: TFA showed more changes
than TTA.
• When amputees walked in sloped settings, they decreased (Preferred
walking speed) PWS considerably more than the control group.
21. CASE STUDY CONT.
• Linear measurement (i.e. upward and down ward motion) was used to achieve
the kinematic data of the participant and the linear variability with the trunk
kinematics were analyzed with use of MATLAB coding.
• Repeated assessments was carried out with analysis of variance (ANOVA)
Instrumented treadmill with 2 force
platforms and 2 independent speed-
adjustable belts.
22. CONCLUSION
• In any walking circumstance, gait analysis is critical,
especially for amputees and prosthesis users.
• By examining how a lower limb amputee walks, runs, or
uses prosthesis, we may distinguish individuals' unique
movements, analyze typical gait patterns, diagnose problems
causing discomfort, and implement and evaluate therapies to
correct anomalies.
