Gait Flashcards
1
Q
Define a step
A
- Initial contact to contralateral initial contact
- Normal step length = 72 cm or ~28.4 in
2
Q
Define stride
A
- Initial contact to subsequent ipsilateral initial contact
- Normal stride length = 144 cm or ~56.7 in
3
Q
Define step width
A
- The lateral distance b/w the heel centers of two consecutive foot contacts
- Normal step width = 7-9 cm or ~2.8-3.5 in
4
Q
Define foot angle
A
- The degree of “toe out” or the line of progression b/w the body & the long axis of the foot
- Normal foot angle = 10-14 degrees
5
Q
Define cadence
A
- The number of steps taken per minute (step rate)
- Average adult cadence = 110 steps/min
6
Q
Define stride time
A
- The time for a full gait cycle to complete
- Average adult stride time = 1 sec
7
Q
Define step time
A
- The time for a right or left step to complete
- Average adult step time = 0.5 sec
8
Q
Define stance time
A
- Time reference foot is on the ground
9
Q
Define swing time
A
- Time reference foot is off the ground
10
Q
Define double limb support time
A
- Time both feet are on the ground that occurs twice during the gait cycle
11
Q
Define single limb support time
A
- Time non reference foot is swinging forward & reference foot is on the ground
12
Q
What is normal gait speed
A
- 1.37 m/s
13
Q
Ways to calculate gait
A
- Measuring the time it takes to cover a given distance
- Measuring the distance covered in a given amount of time
- Multiplying the step rate by the step length
14
Q
What phases of gait are a part of weight acceptance
A
- Initial contact
- Loading response
15
Q
What phases of gait are a part of single limb support
A
- Mid-stance
- Terminal stance
16
Q
What phases of gait are a part of swing limb advancement
A
- Pre-swing
- Initial swing
- Mid-swing
- Terminal swing
17
Q
What are the 4 basic functions of normal gait
A
- Weight bearing stability: think ground reaction forces at different phases of gait & what effect these have on the hip & knee & ankle joint
- Stance limb progression: heel rocker maintains fwd progression from heel strike to foot flat; forefoot rocker does fwd progression to metatarsal heads with heel rise
- Shock absorption: ankle plantar flexion followed by knee flexion
- Energy conservation
18
Q
Difference b/w a hard and soft prosthetic heel during tibial advancement/heel strike
A
- Too hard of a heel will cause the limb to progress forward too fast and result in knee buckling
- Too soft of a heel will squish and lead to the foot going flat to the ground too early results in a knee extension force/thrust
19
Q
Describe weight bearing stability in gait
A
- Muscles around the hip, knee, & ankle sequentially stabilize these joints as the body weight is transferred to the stance limb
- Pattern of muscle activation is dictated by the alignment of the body weight line to the joint
- As the vector moves away from the joint center, a rotational force or moment develops that must be controlled by the opposing muscles to preserve postural stability
20
Q
What are the 3 demands of weight acceptance
A
- Shock absorption
- Initial limb stability
- Preservation of progression
21
Q
What is the most challenging task in the gait cycle
A
- Weight acceptance
22
Q
What are the 2 demands of single limb support
A
- One limb has total responsibility for supporting body weight in both the sagittal & coronal planes
- Progression continues
23
Q
What are the 3 demands of swing limb advancement
A
- Lifting of foot
- Completion of stride length
- Preparation for next stance interval
24
Q
Describe the cost of walking
A
- O2 Cost = Rate of O2 Consumption ÷ Gait Speed
- Minimized at preferred walking speeds
- Higher cost with slow or fast walking
25
Q
What are the weight bearing regions (pressure tolerant) for transtibial prosthesis
A
- Anterior: Patella tendon and Pretibial musculature
- Posterior: Gastric-soleus muscle belly and Popliteal fossa
- Medial: Medial tibial flare
- Lateral: Shaft of fibula
26
Q
Difference b/w terminal stance and pre-swing
A
- In pre-swing the limb is unloaded
- In terminal stance the limb is still under load
27
Q
What is the concern for putting pressure of the fibula shaft
A
- Compression of the fibular nerve
28
Q
What happens to pressure areas that are over muscle bellies overtime
A
- Atrophy which will lead to socket adjustments later on which is normal
29
Q
What is a good landmark to make sure that the socket fits properly
A
- The patella tendon bar area
30
Q
Pressure on tibia through the gait cycle
A
- Loading response: anterior distal/posterior proximal
- Mid-stance: all pressure tolerant weight bearing surfaces
- Terminal stance: anterior proximal/posterior distal
- Pre-swing: anterior distal/posterior proximal
- Initial swing: anterior proximal/posterior distal
- Mid-swing: foot clearance dependent on appropriate suspension & pelvic control on contralateral side
- Terminal swing: anterior distal/posterior proximal
31
Q
A lot of impairments in swing phases are due to inadequate terminal stance True/False
A
- True
32
Q
Define suspension
A
- The interface between the prosthetic and the residual limb
33
Q
What is inadequate suspension
A
- When off loaded the prosthetic is being pulled by gravity causing the leg to be long leads to a compensatory hip hike
34
Q
During mid-stance what force couples are occurring
A
- Medial proximal/lateral distal
35
Q
Describe unleveled bones
A
- Jagged bones from surgery
- Appear more prominent as atrophy occurs
- May lead to skin breakdown during weight bearing
36
Q
What do you due before putting on the prosthesis
A
- Evaluate weight bearing regions
37
Q
What are the goals of prosthetic training
A
- # 1: don’t compromise your PT session with poor fitting limbs that cause you more problems#2: solve issues within your scope without the prosthetist
38
Q
Describe the initial check of the prosthesis
A
- Check height (pub-floor)
- Foot is level in the shoe
- 5-7 degrees socket flexion (means knee flexion or moved anteriorly)
- Weight line is near posterior third of foot
- Pin suspension engages/disengages easily
39
Q
What happens if too much flexion or weight line too far forward?
A
- Rapid knee flexion
- Increased distal tibia pressure
40
Q
Before calling the prosthetist ask what
A
- Take the leg off & put on again
- When in gait does it hurt?: on heel, mid foot, or toe
- Can you duplicate the pain with the leg off?
- Are there pressure areas on the limb you can relate to gait?
41
Q
Describe residual limb pain
A
- Pain in the limb between the end of the residual limb & the next most proximal joint
42
Q
Describe MSK pain for amputees
A
- Amputation has been associated with increased prevalence of secondary MSK pain in the lumbar spine & in the contralateral knee/hip
43
Q
Describe phantom limb pain
A
- Pain distal to the end of the residual limb
- Onset in early post amputation period
- Often nocturnal
- Gradually reduced in intensity & frequency over time
- Can be exacerbated by residual limb pain
44
Q
Describe phantom limb sensation
A
- Non-painful sensations distal to the residual limb
- Wide spectrum of sensory experiences that vary in intensity, frequency, & severity
45
Q
Describe residual limb management through the different stages
A
- Preoperative: desensitization exercises, skin hygiene, & description of types of pain; explain & differentiate b/w residual limb pain, phantom pain, & phantom sensation
- Postoperative: Donning/doffing of ACE wrap or shrinker if appropriate; desensitization exercises, skin hygiene, & description of types of pain
- Pre-prosthetic: care of residual limb
- Prosthetic training: donning/doffing of prosthetic system, use of shrinker when out of the prosthesis, skin checks & skin hygiene, management of sock ply if appropriate, observe pressure points & protect contralateral foot
- Long term follow up: foot care & skin checks
46
Q
Slide 75
A
47
Q
Describe cardiovascular endurance in amputees with prosthetics
A
- Energy cost of walking is greater in amputees
- Higher level amputations are associated with higher energy costs of gait
- Dysvascular amputations demonstrate greater energy cost of gait than those with traumatic amputations
- Self-selected gait speed decreases with higher levels of amputation
- Generally more efficient for an individual with a prosthesis to ambulate with the prosthesis than it is to ambulate w/o the prosthesis using an AD
48
Q
Difference in energy expenditure for over ground walking between transtibial and transfemoral amputees
A
- Energy expenditure for over-ground walking in people with unilateral dysvascular amputations is increased by up to 36% for transtibial and up to 65% for transfemoral amputations
49
Q
Describe the socket-residual limb interface
A
- The static and dynamic pressure distribution of the residual limb within the socket are essential considerations in patient comfort, function, and well-being
- You could have the best prosthetic foot on the market, but if your socket is uncomfortable you’re not going to walk very far
50
Q
Describe a joint and corset
A
- May/may not have a waist belt depending on how prominent the femoral condyles are
- May include posterior check strap to limit full knee extension
- Load-bearing forces were split b/w the socket & a thigh corset
- Primarily indicated for very short residual limb (transtibial)
51
Q
Describe a patella tendon bearing (PTB) socket
A
- Localization of load-bearing pressures soon designated “pressure tolerant” regions, & targeted offloading of regions generally intolerant to pressure
- Patellar tendon bar & medial tibial flare are major WBing areas for a PTB socket
- Total contact socket design has been used for ≥60 years for a comfortable prosthetic fit
52
Q
Describe a total surface bearing (TSB) socket
A
- Globally reduced socks volumes & relatively equal load bearing pressures throughout the entirety of the socket
- Allows increased surface area for WBing
- Shear forces run parallel to the limb surface & are best mitigated through the use of a socket interface
- Normal forces are those that are applied perpendicular to the surface of the limb
53
Q
Viscoelastic interface liners provide reduction of shear at skin surface, these are fabricated from a range of elastic materials including:
A
- Silicone
- Urethane
- Other Gel-like substances
54
Q
What is included in the socket interface
A
- Elastic liners
- Socks
- Foam liners
55
Q
Describe elastic liners
A
- Composed of silicone, urethane, & other thermoset elastomeric materials
- Used with & w/o external fabric covers & imbedded matrices of reinforcing mesh material
- Fabricated in custom & non-custom variants
56
Q
Describe socks
A
- Compressible textiles, occasionally infused w/thermoplastic elastomer gels
- Primarily used to accommodate changes in limb volume but occasionally used as a primary interface b/w the limb & socket
57
Q
Describe foam liners
A
- Nonporous material of soft to moderate durometer, frequently heat contoured over a positive model of the limb to mimic the contours of the socket
- Good option for individuals with fluctuating residual limb volume
58
Q
Compared with traditional PTB-designed interfaces, the use of gel liners reportedly:
A
- Decreases walk aid dependence
- Improves prosthetic suspension when used with a shuttle lock mechanisms compared with supracondylar, cuff, or corset alternatives
- Improves load distribution
- Decreases pain & increases comfort
59
Q
Describe an anatomic suspension
A
- Proximal socket contours are shaped to secure purchase over the bony shape of the femoral condyles
60
Q
Describe a mechanical “locking” liner suspension
A
- Combo of an elastic liner fitted with a distal locking pin which engages a locking mechanism fabricated into the socket
- Suspension results from the suction of the liner & transfers through the locking mechanism attached to the socket
- Reinforcing mesh is frequently impregnated into the liners distally to limit longitudinal dissension of the liner
61
Q
Describe suction suspension
A
- Creation of an airtight socket environment
- Frequently obtained through the use of a proximal sealing sleeve worn against the thigh & outer surface of the socket but alternatively obtained with sealing gaskets worn over the external surface of the interface liner
- During gait when the prosthesis would separate from the limb it results in an increase negative pressure further resulting in an increasing force keeping the prosthesis on the limb
62
Q
Describe a vacuum assisted suction suspension
A
- Similar to suction suspension with the addition of a vacuum element that actively draws air form the socket environment resulting in elevated negative pressure w/o need for initial prosthesis distraction from the residual limb to obtain negative pressure
63
Q
Compared with Total Surface Bearing-designed interfaces with pin locking suspension mechanism, VAS interfaces reportedly:
A
- Reduce time to prosthetic fitting and improve mobility post-operative or post-ulceration
- Decrease step activity
- Decrease pistoning
- Decrease positive pressure in stance phase of gait
- Increase negative pressure in swing phase when walking
- Could decrease daily limb volume changes, maintain a better socket fit
- Improve mobility, comfort, stability, proprioception, functional outcome, overall satisfaction, prosthetic function, and quality of life.
- Reduce skin irritation, cure residual limb wounds faster, and decrease pain.
- More maintenance was required for VAS systems
64
Q
Indications for a vacuum assisted suspension (VAS)
A
- Indicated to decrease daily limb volume changes while facilitating more favorable pressure distribution during gait-
65
Q
Precautions for VAS
A
- VAS requires both awareness & compliance on the part of the end user & are not universally indicated
- Possibility of creating skin blisters when worn improperly
- Requires that the pt has sufficient cognitive ability to know what to watch for & how to fix problems
- Requires more maintenance than other suspension systems
66
Q
Which type of suspension is best among modern suspension optiosn
A
- Vacuum-assisted suspension (VAS) sockets permit the least amount of pistoning within the socket
- Suction suspension
- Pin lock suspension
- Traditional suspension options of supracondylar, cuff, and sleeve suspension provide comparatively compromised suspension
67
Q
Why do we care about sockets & suspension
A
- Socket has been the most important consideration in lower limb prosthesis user satisfaction
- Dissatisfactionn is mainly caused by strains & injuries associated with socket fit
- Pressure distribution (within the socket) directly/indirectly affects the effective indices of user satisfaction
68
Q
Describe heel position and its effects on socket & foot alignment
A
- Heel too low creates excessive extensor moment at the knee in mid-stance, hampering forward progression
- Heel too high creates a flexion moment at the knees in mid-stance leading to early “drop off” & compromise of stance phase stability
- Goal is pylon vertical*
69
Q
Socket and foot alignment during gait
A
- Initial contact: made at the heel, & compression of the prosthetic heel simulates controlled lowering of the foot during loading response
- Mid-stance: WBing forces move anteriorly to the ball of the foot
- Terminal stance: the anterior portion of the prosthetic foot simulates toe extension & the heel rises
- Pre-swing: the individual rolls over the toe & moves into knee flexion for effective shortening of the limb for swing limb clearance
70
Q
Describe the K-levels that are based on the amputee mobility predictor
A
- Level 0: Does not have the ability or potential to ambulate or transfer safely with or without assistance and a prosthesis does not enhance their quality of life or mobility.
- Level 1: Has the ability or potential to use a prosthesis for transfers or ambulation on level surfaces at fixed cadence.
- Level 2: Has the ability or potential for ambulation with the ability to traverse low-level environmental barriers such as curbs, stairs or uneven surfaces.
- Level 3: Has the ability or potential for ambulation with variable cadence.
- Level 4: Has the ability or potential for prosthetic ambulation that exceeds basic ambulation skills, exhibiting high impact, stress, or energy levels.
71
Q
Describe the amputee mobility predictor
A
- Ceiling effect with higher level mobility
- Scores >37 indicate that the pt demos proficient balance, postural stability during sitting & standing, and the ability to vary walking cadence then they are ready to perform activities beyond basic ambulation
- Scores 32-47: have adequate balance with both static & lower level dynamic activities, demo better than average lower limb power, & show competent use of prosthesis
72
Q
Potential functional ability is based on the reasonable expectations of the prosthetist, and treating physician, considering factors including, but not limited to the following:
A
- Pt’s past Hx
- Pt’s current condition including the status of the residual limb & the nature of other medical problems
- Pt’s desire to ambulate
73
Q
Slide 112
A
74
Q
Recommendations or single axis foot
A
- Pts ambulating at a single speed who require greater stability during weight acceptance bc of weak knee extensors or poor balance
75
Q
Biomechanics of a single axis foot
A
- Prosthetic comes into full contact with the floor more quickly during weight acceptance which decreases magnitude of the external knee flexion moment
- This reduces the likelihood of a knee-buckling event, creating a more stable environment for users with weak knee extensors or transfemoral prostheses
76
Q
Recommendation for energy storage & return foot (ESAR)
A
- Pts at elevated risks for overuse injury to the contralateral lower limb & lower back
- Pts capable of variable speed and/or community ambulation
77
Q
Biomechanics of a ESAR
A
- Reductions in the peak ground reaction force experienced by the sound-side limb during weight acceptance which Improved tibial progression into terminal stance
- Shock-absorbing characteristics seem to be more apparent at speeds exceeding self-selected walking velocities
- Reduced energy costs of ambulation are more pronounced at elevated walking speeds, during the negotiation of inclines/declines, and during stair ascent
78
Q
K1 level feet
A
- Single axis feet are appropriate
- Solid ankle cushioned heel (SACH) foot may not be appropriate for heavier pts
79
Q
K2 level feet
A
- Lightweight, flexible heel, multi-axial ankle
- Modest energy return
- Flexible bumper cushions dampen PF from heel strike to foot flat (stiffness/softness can be changed)
80
Q
K3 level feet
A
- Integrated pylon is the lightest design
- ESAR
- Typically carbon fiber or fiberglass
- Reduce energy consumption
- Offer increased ankle ROM
- Reduce sound side loading
- Variable degree of frontal plane motion (inversion/eversion)
- Microprocessor feet: heavier than most ft, require nightly charging, currently limited to single axis, not appropriate for very high activity or running, responses to changes in incline/decline, walking speed, and shoes
81
Q
Line of gravity through the body in standing
A
- anterior to ankle
- anterior to knee
- posterior to hip
- anterior to 2nd sacral vertebra
- straight through the ear hole
82
Q
Describe loading response 0-12% & muscles activated
A
- weight is rapidly transferred onto the outstretched limb
- hip stability, controlled knee flexion, & ankle PF
- Hip 20º flexion
- Knee 15º flexion
- Ankle 5-10º PF
- hip extensors & abductors, quads, pretibial muscles/DF
83
Q
Describe midstance 12-30% & muscles activated
A
- body progresses over single limb
- controlled tibial advancement
- Hip 0º
- Knee 5º flexion
- Ankle 5º DF
- hip abductors, quads initially, gastroc/soleus
84
Q
Describe terminal stance 30-50% & muscles activated
A
- body moves ahead of the stance limb
- controlled ankle DF with heel rise & trailing limb posture
- Hip 20º ext
- Knee 0-5º flexion
- Ankle 10º DF
- gastroc/soleus
85
Q
Describe pre-swing 50-62% & muscles activated
A
- rapid unloading of trailing limb as weight is transferred to opposite foot
- passive knee flexion to 40º & rapid ankle PF
- Hip 10º ext
- Knee 40º flexion
- Ankle 15º PF
- hip adductors
86
Q
Describe initial swing 62-75% & muscles activated
A
- thigh begins advancement as the foot comes up off the floor
- hip flexion 15º & knee flexion 60º
- Hip 15º flexion
- Knee 60º flexion
- Ankle 5º PF
- hip flexors, hamstrings, pretibial muscles/DF
87
Q
Describe mid swing 75-87% & muscles activated
A
- continued thigh advancement with foot clearance & begin knee extension
- hip flexion 25º, ankle DF 0º
- Hip 25º flexion
- Knee 25º flexion
- Ankle 0º
- hip flexors initially then hamstrings, pretibial muscles/DF
88
Q
Describe terminal swing 87-100% & muscles activated
A
- final knee extension in preparation for contact with ground
- knee extension to neutral
- Hip 20º flexion
- Knee 5º flexion
- Ankle 0º
- hamstrings & add/abductors, quads, pretibial muscles/DF
