PROSTHETIC CPM EVALUATION EXAM 2026 QUESTIONS
AND ANSWERS GRADED A+
✔✔Multiaxial feet - ✔✔Pros: Accommodates uneven terrain, decreases stress on skin
and prosthesis
Con: Increased weight/maintenance, cost
✔✔Dynamic Response feet - ✔✔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
✔✔K1-K2 knees - control - ✔✔Fiction/mechanical - single speed ambulators
May have manual lock feature
Weight activated stance control
✔✔K3-4 knees - control - ✔✔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")
✔✔Microprocessor knees - ✔✔Pros: improve environmental obstacle negotiation,
increased walking speed on uneven terrain, reduced falls, increased confidence
Cons: heavy
✔✔Manual lock knee feature - ✔✔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
✔✔Single axis knee feature - ✔✔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
✔✔Weight activated stance control knee feature - ✔✔"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
✔✔Polycentric - ✔✔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
✔✔Single axis outside hinges - ✔✔PFFD, KD
Free swinging
Pros: avoid knee length discrepancy, durable
Cons: no inherent friction control, no inherent stability, ugly
✔✔Building a recommendation: - ✔✔Socket design
Ultralight
Acrylic
Suspension type
Interface (liners, socks, etc)
Alignable components
Knee
Foot
✔✔Hemipelvectomy Socket Principles - ✔✔Weightbearing: IT/soft tissue
Suspension: Iliac crests
✔✔Knee disarticulation socket principles - ✔✔Subischial or 3/4 sockets are appropriate
Can use anatomical suspension over the condyles
✔✔TF Ischial Containment Socket Principles - ✔✔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 - ✔✔Hydrostaic weightbearing
Lower trimlines
Ramal buttress for ML control
✔✔TF Subischial Socket Principles - ✔✔Much lower trimlines - KD
Use with anatomical suspension or vacuum
Long limbs, requires good control and normal ROM of hip
✔✔TF Quad Socket Principles - ✔✔4 well-defined walls
Rectangular shape
Ischial/gluteal weightbearing
AND ANSWERS GRADED A+
✔✔Multiaxial feet - ✔✔Pros: Accommodates uneven terrain, decreases stress on skin
and prosthesis
Con: Increased weight/maintenance, cost
✔✔Dynamic Response feet - ✔✔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
✔✔K1-K2 knees - control - ✔✔Fiction/mechanical - single speed ambulators
May have manual lock feature
Weight activated stance control
✔✔K3-4 knees - control - ✔✔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")
✔✔Microprocessor knees - ✔✔Pros: improve environmental obstacle negotiation,
increased walking speed on uneven terrain, reduced falls, increased confidence
Cons: heavy
✔✔Manual lock knee feature - ✔✔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
✔✔Single axis knee feature - ✔✔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
✔✔Weight activated stance control knee feature - ✔✔"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
✔✔Polycentric - ✔✔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
✔✔Single axis outside hinges - ✔✔PFFD, KD
Free swinging
Pros: avoid knee length discrepancy, durable
Cons: no inherent friction control, no inherent stability, ugly
✔✔Building a recommendation: - ✔✔Socket design
Ultralight
Acrylic
Suspension type
Interface (liners, socks, etc)
Alignable components
Knee
Foot
✔✔Hemipelvectomy Socket Principles - ✔✔Weightbearing: IT/soft tissue
Suspension: Iliac crests
✔✔Knee disarticulation socket principles - ✔✔Subischial or 3/4 sockets are appropriate
Can use anatomical suspension over the condyles
✔✔TF Ischial Containment Socket Principles - ✔✔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 - ✔✔Hydrostaic weightbearing
Lower trimlines
Ramal buttress for ML control
✔✔TF Subischial Socket Principles - ✔✔Much lower trimlines - KD
Use with anatomical suspension or vacuum
Long limbs, requires good control and normal ROM of hip
✔✔TF Quad Socket Principles - ✔✔4 well-defined walls
Rectangular shape
Ischial/gluteal weightbearing
