2. Goals
Gait review
Key muscles, joint mechanics
Common conditions for orthotics
Lower limb orthotic approach
Examples
3. Normal gait = progression of
passenger unit through
space with stability and
minimal energy output.*
Keep center of gravity in tightest spiral
Most efficient CG path = line, only with wheels
Perry, J Atlas of Orthotics
6. Terminology
Gait Cycle: Sequence of events from
initial contact of one extremity to
the subsequent initial contact on the
same side
7. Gait terminology
Stride length: Distance from initial contact
of one extremity to the subsequent initial
contact on the same side (x= 1.41 m)
Step length: Distance from initial contact
of one extremity to the initial contact on
the opposite side (x= 0.7 m)
8. Terminology
Cadence: The step rate per minute
(x= 113 steps per min)
Velocity: The speed at which one
walks
(x= 82 m/min)
9. Normal Gait
Classic Gait Terms:
1) Heel Strike
2) Foot Flat
3) Midstance
4) Heel Off
5) Toe Off
6) Initial Swing/ Midswing/ Terminal Swing
15. Progression
Mostly from forward fall of body
mass as it progresses in front of
loaded foot, ankle moves into DF with
rapid acceleration as heel rises
Swing limb generates second
progressional force as stance limb
goes into single support phase, must
occur to prepare for forward fall
16.
17.
18. Energy consumption
Acceleration & deceleration needs
Swinging mass of leg must be
decelerated by eccentric contraction
of extensors and counterforce
(acceleration) of body
Forward falling body must be
decelerated by shock absorption at
initial contact = heel strike
19. Eccentric energy
consumption is high
Pretibial and quadriceps contraction
at initial contact with eccentric
control of tibial shank in loading
phase on stance leg.
Results in 8:5 ratio for energy in
deceleration or control activity vs.
propulsion activity
20. Determinants of gait
Foot, ankle, knee and pelvis
contributions to smoothing center of
gravity motion to preserve energy
Inman APMR 67
21. Determinants
1) Pelvic Rotation
2) Pelvic Tilt
3) Lateral pelvic motion
4) Knee flexion in midstance
5) Knee motion throughout gait cycle
6) Foot and ankle motion
22. Determinants
Foot & ankle motion
Pelvic rotation 4 degrees Smooths out abrupt
saves 6/16 vertical drop changes in accel/decel
Pelvic tilt 5 degrees, & direction of body
saves 3/16 vertical motion
excursion Knee contributes also
Knee flexion 15 degrees Converts CG curve into
lowers CG 7/16 smooth sine wave < 2
inch amplitude
total savings = 1 inch CG horizontal translation
per leg reduced by leg alignment
reduces side to side
sway for stability by >
4 inches
28. Joint stability in gait
Determined by relationship between
muscle support, capsule & ligamentous
support, articular relationships and
lines of force
35. Leg length difference
< 1.5 in, see long side shoulder
elevation with dipping on short leg
side
Compensation with dropping pelvis on
short side
Exaggerated hip, knee, ankle flexion on
long side
> 1.5 in, different compensation such
as vaulting on short leg, trunk lean to
short side, circumduct long leg
36. ROM loss or ankylosis will
show proximal compensation
with or without velocity
changes.
37. Other orthopedic problems
affect gait*
Foot equinus gives steppage gait to clear
the relatively longer leg
Calcaneal deformity changes push off and
initial contact
38. Gait changes from
orthopedic issues
Joint instability gives unstable motion
and fear, reduced stance phase
Pain reduces stance typically
Spine pain may reduce gait speed to
reduce impact
39. Hemiplegia gaits
Extensor synergy allows ambulation
Hip & knee extension, hip IR, foot & toe
PF and foot inversion
Difficulty in loading phase or clearing
the “longer” plegic limb gives step-to
gait.
40. Hemiplegia
1) Asymmetric Gait
2) Step length shortened on the plegic side
3) Decreased knee and hip flexion on swing
phase
4) Shortened stance phase
5) Upper extremity held in flexion and
adduction
41. Lower motor neuron gaits
Hip extensor weakness gait
Trunk & pelvis posterior after heel
strike
Glut medius limp
pelvis drops if uncompensated
trunk shift if compensated
Hip flexor weakness
Leg swung by trunk rotation pulling leg
on hip ligaments
42. Lower motor neuron gaits
Quadricep weakness: forcible extension
using hip flexors, heavy heel strike and
forward lean over heel to keep force
anterior to knee joint.
Gastroc/soleus weakness: poor control of
loading phase DF >> compensation is delay
with resulting knee bending moment and
more quad extensor needs. Reduced
forward progression of limb with push off
into swing*
43. Lower motor neuron gaits
Dorsiflexor weakness gives steppage
gait
Foot slap in fast walk with mild weakness
and if some strength, may be noticable
with fatigue as eccentric TA activity
fails
Forefoot = initial contact point if no
strength for DF present
47. Leg joint alignment orthoses
Use with & without weight bearing
features
Most common in knee support for RA
induced ligamentous loss
Form fitting shells better than bands
Alignment of knee joint is key
Typically use single axis knee joints for
these orthoses
48.
49. LE weakness orthoses
AFO’s HKAFO’s
Double metal Reciprocating Gait
upright Orthosis
Plastic Functional
Molded
Electrical
off shelf
Stimulation (FES)
VAPC
KAFO’s
Many designs for
band configurations
Metal vs. plastic
50. AFO’s
Most common orthotic
Stabilizes ankle in stance
Helps clear toe in swing
Gives some push off in late stance to
save energy
Remember effects on knee!!
51. AFO’s
Double metal upright allows for
anterior and posterior stops and
spring assist for DF & PF force
generation.
Hinged molded AFO can be similar
Mediolateral stability is good but can
be enhanced with T-straps
52.
53.
54.
55. Knee effects of PF stops
PF stop helps weak DF & swing
clearance but stops PF of foot at heel
strike, force line behind knee
destabilizes.
Minimal PF stop or just spring assist to
pick toe up in swing should be used for
flaccid paralysis and only few degrees of
DF position for PF stop in spastic
paralysis.
56. Posterior PF stop should
allow adequate toe clearance
in swing but not excessive
DF to increase knee bending
moment at heel strike.
59. Effects of DF stops
Anterior DF stop (plus sole plate in shoe)
enables push off and propulsion of limb
and pelvis
Normal forces if DF stop in 5o PF
Use for PF weakness, restores step length
on opposite side and knee moments
normalize.
Spring doesn’t help
Too much PF angle gives genu recurvatum
Stabilizes knee with absent gastroc/soleus
eccentric knee extension help in stance
66. Plastic AFO considerations
Light weight
Variable shoes can effect
performance
Skin irritation very real risk
Contraindicated in diabetic neuropathy
or poorly compliant patient with skin
checks
Minimal help for PF weakness, mostly
for DF weakness
Can help with arch support
68. Knee orthoses
Commonly used for genu recurvatum
Swedish knee cage
3 way knee stabilizer
Medial/lateral laxity
Joint system with thigh & calf cuffs
Axial derotation braces
Axial rotation control plus angular
control in sagittal and frontal planes
71. KAFO’s used in SCI, conus or
cauda equina injuries
T10 is often cutoff level, use swing to
gait with locked knees, considerable
energy expenditure
72. Knee stability added when
AFO not able to control knee
Continue to utilize rigid foot plate
and DF stop to help push off and PF
stop to clear toe in swing
73.
74. Knee stability via 3 force
application
Anterior force to stop knee buckling
2 posterior counterforces at thigh &
1 at calf
Shoe level counterforce keeps lower
leg from posterior motion in closed
chain loading
Double stance occurs in initial and terminal 10% of stance, thus middle 40% of stance is single limb support
Pre-tibial muscles eccentrically slow plantarflexion after heel strike, some action in stance for sub-talar influence and some activity in swing for toe clearance. Gastroc/soleus with peak in push off for CG propulsion but also eccentrically controls shank progression over ankle. Quads peak after heal strike to absorb knee flexion. RF active in late stance with flexed hip and knee to reduce heel rise. Quads also active in early swing to keep lower leg swinging on femur. Hamstrings with 2 peaks around heel strike. Firstin terminal swing to slow forward swing with hip extension and knee flexion action in open chain role. Second is closed chain role with foot contact to extend knee and hip for stability. Variable late peak helps with extension in push off.
Glut medius and minimus give abduction support in initial contact& early stance to reduce pelvic tilt. Adductors peak at initial contact, possibly from hamstring portion of adductor magnus slowing hip flexion & possibly to help with femur internal rotation in closed chain role. Second adductor peak at end of stance may help accelerate the limb forward into swing with muscles aiding hip flexion. Glut max absorbs heel strike shock eccentrically, keeps hip and knee extended. Second peak with push off may help hip and knee extension to propel body on fully extended stance leg. Show gluts as knee extensor in closed chain model Spine erector mass active on heel strike each side to prevent trunk flexion over pelvis and provide medial/lateral stability.
Lowest = normal +/- 1 SD next = amputee with suction socket prosthetic next = amputee with pylon next = forearm crutch use
May see hip OA patients lean over stance leg to reduce glut medius contraction, shoulder dip. May see external rotation of affected leg due to hip effusion.
Keeps line of force behind knee when compensate for gastroc/soleus weakness.
Heel cutting or cushioned heel wedge moves point of ground reaction force contact forward and brings force line closer to knee axis of rotation.
Considerable forces are measured with variable strap configurations which can cause tissue damage in insensate skin. Cyclic ambulation reduces this effect, but must avoid bony prominences and use adequate straps to distribute forces. Shear forces at knee also vary with strap design.
