PROSTHETIC CPM EXAM WITH COMPLETE QUESTIONS AND ANSWERS | GUARANTEED TO PASS| 100% ACCURATE ANSWERS
Anterior suspension strap (inverted Y strap) - RIGHT ANSWER -Location through the delto-pectoral groove, Y forks 1" inferior to the clavicle
Base plate position (TH) - RIGHT ANSWER -25mm proximal to end of limb
Posterior lateral quadrant of humerus
Move proximal lateral: fix force problem
Move distal/medial: fix excursion problem
Building a recommendation: - RIGHT ANSWER -Socket design
Ultralight
Acrylic
Suspension type
Interface (liners, socks, etc)
Alignable components
Knee
Foot
Clues: Anterior distal pressure - RIGHT ANSWER -Problem: too much pressure
Solution: pretibial pads, extend socket
Clues: Anterior proximal redness - RIGHT ANSWER -Problem: excessive pressure anterior/proximal
Solution: socket too extended (dynamic) flex socket
Clues: bilstering/discoloration of distal limb (socket fit is correct) - RIGHT ANSWER -Problem: milking on the limb due to donning the liner incorrectly
Solution: don liner without air at distal end
Clues: Delivered wearing 3 ply socks, now back wearing 10 ply socks and has redness/pain - RIGHT ANSWER -Problem: too many socks
Solution: remove socks, educate sock ply management
Clues: Knee disarticulation using excessive amount of socks - RIGHT ANSWER -Problem: Volume too large?
Solution: pad socket
Clues: Lateral distal pressure - RIGHT ANSWER -Problem: Foot too inset
Solution: outset foot
Clues: patient no longer fitting in socket today but fit yesterday - RIGHT ANSWER -Problem: swelling (ate salty meal, not wearing shrinker at night)
Solution: educate patient on limb volume changes
Clues: redness at distal patella, loose fit - RIGHT ANSWER -Problem: socket fitting too large
Solution: add socks, educate sock ply management
Clues: Symes pain on medial/lateral malleolus - RIGHT ANSWER -Problem: too much pressure? Not in socket all the way?
Solution: Make sure malleoli are reaching the appropriate reliefs, relieve area if necessary
Clues: Symes pediatric redness on malleoli after growth spurt - RIGHT ANSWER -Problem: increased pressure due to growth
Solution: onion layer socket to allow room for relieving
Clues: TF pain and redness on lateral distal femur - RIGHT ANSWER -Problem: lack of ML stability in the socket
Solution: ensure ischial containment, pad just proximal to distal lateral femur, adduct socket slightly
Clues: Transtibial pain/redness on distal end, distal patella, and fib head - RIGHT ANSWER -Problem: bottoming out
Solution: add sock(s)
Clues: transtibial with fibula tibia - RIGHT ANSWER -Problem: danger of putting distal pressure on fibula
Solution: Provide relief for the fibula inside the socket
Clues: Upper extremity terminal device opening with elbow flexion - RIGHT ANSWER -Problem: EFA too proximal
Solution: move EFA distal
Clues: Upper extremity terminal device will not open all the way - RIGHT ANSWER -Problem: housing is impacting, crosspoint incorrect location, CAS too loose
Solution: check housing, move crosspoint distal to C7 and slightly to sound side, tighten CAS
Clues: Verrucous hyperplasia on distal end - RIGHT ANSWER -Problem: lack of total contact
Solution: add distal end pad/remake socket to provide total contact
Control attachment strap (CAS) location - RIGHT ANSWER -distal 1/3 of scapula
Crosspoint location - RIGHT ANSWER -Inferior to C7 toward the sound side
increased comfort alternatives at cost of excursion: sewn, northwestern ring, dual ring, expanded crosspoint, baha
Dynamic Response feet - RIGHT ANSWER -Pros: use with increased activity level, energy storing, reduces impact to joints and the residual limb, decreased walking effort/increased push off
Cons: increased cost/weight
E400 Elbow - RIGHT ANSWER -Requires 1.5-2" excursion to cycle (2-3 lb of force)
Requires 2.5" to lock/unlock (7-9 lb of force)
Motions: GH flexion, scapular protraction
To lock/unlock: depression, extension, and abduction
Elbow flexion attachment position - RIGHT ANSWER -25 mm anterior, 30 mm distal to joint center
Move proximal: less excursion required but more force
Move distal: less force required, but more excursion
Elevated vacuum (TF) - RIGHT ANSWER -mechanical or electronic
Pros: Improved proprioception, Can be used with subischial trimlines
Cons: requires cognitive ability, pump adds weight
Elevated vacuum (TT) - RIGHT ANSWER -mechanical or electric pump
Pros: Good for volume management, increased control/proprioception, wound care advantages
Cons: requires sleeve, cognitive ability, pump adds weight, precise fit needed
Excursion amplifier - RIGHT ANSWER -doubles the amount of excursion but requires double the force
External power feet - RIGHT ANSWER -K1-3, all cadence/terrain
Pros: propulsion, dorsi/plantarflexion
Cons: batteries/weight/cost/processing speed
Figure 8 Harness - RIGHT ANSWER -Control and suspension
Figure 9 Harness - RIGHT ANSWER -Control only
Flexible keel - RIGHT ANSWER -Pros: provides easy rollover, smooth transition from heel strike to toe off, allows natural sagittal plane motion, reduces socket foreces on residual limb, improves walking safety, reliable
Cons: limited push off, increased cost
Frontal TF dynamic alignment goals - RIGHT ANSWER -Adequate suspension
Width of base of support
Control of pelvis during prosthetic stance
Quality and pattern of prosthetic swing
Hemipelvectomy Socket Principles - RIGHT ANSWER -Weightbearing: IT/soft tissue
Suspension: Iliac crests
Hip joint + Pelvic band (TF) - RIGHT ANSWER -Sock interface
Pros: Maximal ML control, Good if weak abductors or short residual limb, some rotational control
Cons: heavy, bulky, pistoning, hard to don, uncomfortable when sitting
Pelvic band b/w iliac crests and trochanters
Joint 12mm anterior and 25mm proximal to GT
Info for Px Eval - RIGHT ANSWER -Name, Age, DOB, Sex
Ht, Wt
Meds, comorbidities
Amp site/cause/date
ADLs/vocational/avocational
Goals!
Home status/environment
Work status/environment
PT/OT, assistive devices used
Current/previous px treatment
MMT, ROM
Sensation
Condition of residual limb
Condition of contralateral/upper extremities
K-level/AMP
Ischial containment trimlines - RIGHT ANSWER -Anterior 50mm (2") proximal to IT
Posterior 25mm (1") proximal to IT
Medial at ischial level in line of progression
Lateral 90 mm (3") proximal to IT
Joint + corset (TT) - RIGHT ANSWER -Pros: provides max knee stability, very secure, can help with recurvatum. thigh weightbearing & unloading of limb, heavy duty, don sitting
Cons: heavy, bulky, ugly, pistoning
K0 - RIGHT ANSWER -The patient does not have the ability or potential to ambulate or transfer safely
K1 - RIGHT ANSWER -Prosthesis for transfers or ambulation at fixed cadence; household ambulator
K1 feet - RIGHT ANSWER -SACH, Single axis, safe
K1-K2 knees - control - RIGHT ANSWER -Fiction/mechanical - single speed ambulators
May have manual lock feature
Weight activated stance control
K2 - RIGHT ANSWER -Ability to traverse low level environmental barriers; limited community ambulator, fixed cadence
K2 feet - RIGHT ANSWER -Multiaxial, flexible keel
K3 - RIGHT ANSWER -Ambulation at variable cadence; prosthetic utilization beyond simple locomotion; "unlimited" community ambulator, traverse most environmental barriers
K3-4 - RIGHT ANSWER -Dynamic response (also often multiaxial)
With vertical shock
Shock & torque absorbers
K3-4 knees - control - RIGHT ANSWER -Fluid (cadence responsiveness) hydraulic or pneumatic
-Pros: variable cadence, swing and stance control, more natural gait
-Cons: increased weight/maintenance/cost
Microprocessor (fluid controlled by "computer chip")
K4 - RIGHT ANSWER -Exceeds basic ambulation skills, exhibiting high impact, stress, or energy levels; child, active adult, or athlete.
KD Suspension - RIGHT ANSWER -Anatomical with foam liner - Pros: rotational control, increased suspension in swing phase; Cons: suspension localized to one area, not able to use with fluctuating edema
Cushion liner
Window/door
Boa
Lacer
Seal-in suction
Knee disarticulation socket principles - RIGHT ANSWER -Subischial or 3/4 sockets are appropriate
Can use anatomical suspension over the condyles
Lateral suspension strap - RIGHT ANSWER -Crosses at the level of C7
Attaches over the apex of the shoulder slightly anterior to the acromion
Liner + Lanyard (TF) - RIGHT ANSWER -Pros: Seated donning, Great for low mobility/balance, positive lock
Cons: pistoning/milking of tissue, single point connection, must have good hand strength
Liner + Pin (TF) - RIGHT ANSWER -Pros: Seated donning, positive lock
Cons: difficult due to pin angle, soft tissue movement, pistoning/milking of tissue
Liner w/ Lock or Lanyard (TT) - RIGHT ANSWER -Pros: positive lock, lower profile, liner protects against shear, increased ROM
Cons: can get pistoning/milking, must have full function of upper extremities for liner use, need good subcutaneous tissue,
Manual lock knee feature - RIGHT ANSWER -Maximum stance phase stability - K1-K2
prosthesis made slightly shorter
use with a single-axis foot is desirable
Pros: doesn't require strength, can be used with blind or bilateral patients, extremely stable bc eliminates knee flexion
Cons: forces gait deviation
Max sock ply before new socket is indicated - RIGHT ANSWER -15-20 ply
Microprocessor knees - RIGHT ANSWER -Pros: improve environmental obstacle negotiation, increased walking speed on uneven terrain, reduced falls, increased confidence
Cons: heavy
Multiaxial feet - RIGHT ANSWER -Pros: Accommodates uneven terrain, decreases stress on skin and prosthesis
Con: Increased weight/maintenance, cost
Normal anatomical pronosupination - RIGHT ANSWER -90 supination
80 pronation
(preserved if 60% of the limb remains)
Polycentric - RIGHT ANSWER -K1-K4; 4-bar linkage, moving center of rotation centrode proximal and posterior to weight line
Pros: shorten in swing phase, cosmetic in sitting, stability inherent in alignment, stable during stance
Cons: Low stability at toe-off, contraindicated for bilateral, increased weight/maintenance/cost
Quad trimlines - RIGHT ANSWER -Anterior: 2.5" proximal to IT
Medial: at ischial level
Lateral: 2.5" proximal to IT
Posterior: at ischial level
SACH feet - RIGHT ANSWER -Pros: provides stability in early stance
Cons: DF stop increases knee hyperextesion
Sagittal TF dynamic alignment goals - RIGHT ANSWER -Knee stability throughout stance
Smooth loading response
Symmetry of step length and duration
Quality of knee flexion during late stance and swing
SC-SP (TT) - RIGHT ANSWER -Supracondylar with suprapatellar bar (quad bar), easy donning
Pros: knee stability (AP and ML), simple, short limbs, good for pts with upper limb involvement, low maintenance, don't need good hygiene, good for less active, easy donning
Cons: higher trimlines, bulkier, less cosmetic, restrict knee ROM
Scarpa's triangle - RIGHT ANSWER -Inguinal ligament, sartorius, adductor longus
Seal-in liner (TF) - RIGHT ANSWER -Pros: Improved proprioception, perceived as lighter, eliminates pistoning, shear forces moderated by liner
Cons: must have good hygiene, must have good hand strength, must stand to don, need precise fit
Seal-in suction (TT) - RIGHT ANSWER -Pros: one way valve, solid connection, no pistoning, active patients, very secure
Cons: little tolerance for volume fluctuation, must have good hygiene
Shoulder saddle - RIGHT ANSWER -For heavy duty patients
Silesian belt/TES belt - RIGHT ANSWER -Pros:Auxiliary, controls rotation, allows for volume changes
Cons: not good for independent suspension, allows pistoning
Attached 6mm posterior and 6mm proximal to GT
Pulls into adduction
Single axis feet - RIGHT ANSWER -Pros: inexpensive, durable
Cons: rigid forefoot, not energy efficient, not suitable for uneven surfaces
Single axis knee feature - RIGHT ANSWER -Fixed rotation point; stability via alignemnt or muscular control; constant friction - K1-K2
Pros: longer residual limb with good muscle control, children, inexpensive, durable
Cons: must have strong hip extensors and good balance, decreased stability
Single axis outside hinges - RIGHT ANSWER -PFFD, KD
Free swinging
Pros: avoid knee length discrepancy, durable
Cons: no inherent friction control, no inherent stability, ugly
Skin fit suction (TF) - RIGHT ANSWER -Pull sock + expulsion valve
Pros: Improved proprioception, Perceived as lighter, Eliminates pistoning
Cons: Can be hard on skin, can't have volume fluctuation, must stand to don, need precise fit
Sleeve (TT) - RIGHT ANSWER -Pros: minimizes pistoning, can be cosmetic by masking trimlines, can be used as auxiliary suspension, can be used for lots of patients
Cons: hot, doesn't last very long, can reduce ROM, large thighs may cause it to roll down
Subischial triangle - RIGHT ANSWER -Inferior ramus, gracilis, semitendinosis
Supracondylar (TT) - RIGHT ANSWER -pelite liner with wedge, can have removable brim (ML-PML =12)
Pros: knee stability (ML), simple, short limbs, good for pts with upper limb involvement, low maintenance, don't need good hygiene, good for less active, easy donning
Cons: higher trimlines, bulkier (thicker), restrict knee ROM
Supracondylar cuff/strap (TT) - RIGHT ANSWER -Pros: Simple, suprapatellar suspension, low maintenance, don't need large PML-ML difference, adjustable
Cons: Higher trimlines, ugly, bulky, pistoning, may impair circulation
TD doesn't fully open at waist/mouth (TH) - RIGHT ANSWER -Excursion problem
Solution: tighten CAS, check housing clearance, move EFA distal, move baseplate posterior/distal/medial, add Northwestern ring/Baha/etc; add Z strap
TD doesn't open all the way (TR) - RIGHT ANSWER -Excursion problem
Solutions: check position of cross point, tighten or lower CAS
TD opens before/during elbow flexion (TH) - RIGHT ANSWER -Force problem
Solution: move EFA distal, more bands, baseplate anterior/prox/lateral, add forearm lift assist, second base plate, lighter TD, shorten forearm section, check housing clearance, teflon/wax
TD too difficult to open (TR) - RIGHT ANSWER -Force problem
Solutions: remove rubber band, check for sharp angles on cabling, add teflon/wax to housing
TF Bench Alignment - RIGHT ANSWER -5* socket flexion (+contracture)
6-7* socket adduction (or match sound)
Socket medial wall parallel to line of progression
Knee: 5-25 mm posterior to weightline, external rotation 3-5*
Foot: 12-37mm outset from IT, 5-7* external rotation
TF Ischial Containment Socket Principles - RIGHT ANSWER -Femur held in adduction
Very intimate fit
Triangular shape
ML compression
Indicated for: shorter limbs, requires less voluntary control
Potential for ischial weightbearing, high proximal trimline
Gluteal and hydrostatic weightbearing
Triangular shape
TF MAS (ramal containment) Socket Principles - RIGHT ANSWER -Hydrostaic weightbearing
Lower trimlines
Ramal buttress for ML control
TF max LLD - RIGHT ANSWER -1/4"
TF Quad Socket Principles - RIGHT ANSWER -4 well-defined walls
Rectangular shape
Ischial/gluteal weightbearing
AP control - Lack of ML support
Contours for flexors/extensors
Indicated for longer limbs, good voluntary control, previous user
TF Subischial Socket Principles - RIGHT ANSWER -Much lower trimlines - KD
Use with anatomical suspension or vacuum
Long limbs, requires good control and normal ROM of hip
TH Cable Clearances - RIGHT ANSWER -Cable 3mm between hanger and proximal housing (extend and pronate)
Housing 3mm at proximal and distal ends of cabling, 6mm between proximal and distal housings at elbow (flex, supinate, open TD)
TH Cable System Validation Criteria - RIGHT ANSWER -50% efficiency (force at TD/force at hanger)
TD stays closed with elbow flexion
45* GH flexion to activate elbow
Shoulder ROM should be 90* abduction, 90* flexion, 30* extension
Forearm resists 3lb of internal/external rotation
** requires 4.5-5" of excursion total
TR Cable System Validation Criteria - RIGHT ANSWER -70% efficiency (force at TD/force at hanger)
Elbow flexion w/in 10* of anatomical
Retain 50% available pronosupination
Lift 50 lb or 1/3 of body weight (figure 8)
50 lb axial pull should not displace 12-25mm
Trouble shooting tools - RIGHT ANSWER -Lipstick, corset stay, clay/playdough
TT acceptable amount of pistoning - RIGHT ANSWER -1cm
TT appropriate amount of varus thrust - RIGHT ANSWER -1cm
TT Bench Alignment - RIGHT ANSWER -5* socket flexion (+contracture)
5* socket adduction (or match sound)
Foot: 37mm posterior to midline (SACH) or 1/3 of foot (DR)
Foot: 12 mm inset to midlineder
TT Hydrostaic - RIGHT ANSWER -Fluid density loading and tissue elongation
Casted under pressure
TT Interfaces - RIGHT ANSWER -Socks: also for volume management
Foam/pelite liner: custom, easily adjustable, durable
Gel liners: cushion/flow, hot, prevents shear
Flexible inner socket: reduce edge pressure, reliefs in outer
TT loading response knee flexion - RIGHT ANSWER -20*
TT PTB SCSP Socket Design - RIGHT ANSWER -Same as PTB with quad bar
Provides knee stability
Requires PML ML by at least 12 mm
TT PTB Socket Design - RIGHT ANSWER -Indicated for short or bony limbs
Rotational control
Depressions: MPT bar, medial flare, medial shaft, pretibial area, politeal area, lateral fibula shaft, interosseus space
Buildups: tibial crest, lateral flare, fib head, distal fibula, distal anterior tibia
Pros: prevents rotation, strategic loading
Cons: Scar tissue in loading areas, can be too much for MPT for some patients
TT socket pressures: Prox lateral, distal medial - RIGHT ANSWER -Too much adduction
Foot too outset
TT socket pressures: prox medial, distal lateral - RIGHT ANSWER -Too much abduction
Foot too inset
TT socket pressures: proximal anterior, distal posterior - RIGHT ANSWER -Anything that results in strong knee extension moment
Foot too anterior
Foot too plantarflexed
TT socket pressures: proximal posterior, distal anterior - RIGHT ANSWER -Anything that results in strong knee flexion moment
Foot too posterior
Foot too dorsiflexed
TT too few socks - RIGHT ANSWER -Redness: Distal fib head, distal patella, distal end of limb
TT too many socks - RIGHT ANSWER -Redness: tibial tubercle, prox aspect of fib head, verrucose hyperplasia
TT TSB Socket Design - RIGHT ANSWER -Fleshy limbs
Lack of rotational control
3-5% global reduction tapering to zero at distal
***Must be used with liner with high flow (TPE)
Pros: distributes weightbearing
Cons: lack of rotational control, does not relieve for extremely bony patients or neuromas
Waist belt (TT) - RIGHT ANSWER -Pros: secure, historic, knee extension assist
Cons: bulky, ugly, pistoning
Weight activated stance control knee feature - RIGHT ANSWER -"safety knee" good for new amputees
Pros: knee is locked when weight is through it - good stability in stance phase, good if weak hip extensors, poor balance, and short TF
Cons: not for active or stable patients, delayed swing phase, must unload fully to sit