What does the foot being displaced medial cause
Pushes knee into varus (more lateral thrust)
What does the foot being displaced lateral cause
Pushes knee into valgus
What does posterior displacement of the foot cause
DF and knee flexion
What does anterior displacement of the foot cause
PF and hyperextension
What causes the knee to remain extended (5)
- Foot too anterior
- Foot too plantarflexed
- Heel cushion too soft
- Heel on shoe too low
- Excessive use of knee extensors or weak quadriceps
What causes excessive knee flexion (6)
- Foot too posterior
- Foot too dorsiflexed
- Heel on shoe too high
- Heel cushion too firm
- Increased pressure against anterodistal tibia
- Weak knee extensors resulting in flexion that is not smooth
What causes early knee flexion (4)
- Excessive posterior displacement of the foot in relation to the socket
- Excessive dorsiflexion
- Prosthetic foot keel is too short
- Excessive socket flexion (may occur with a resolving knee flexion contracture)
What causes delayed knee flexion (2)
- Foot too anterior
2. Foot too plantarflexed
What causes a foot whip (2)
- Suspension cuff not aligned evenly
2. Prosthesis is rotated
What motion causes a medial whip
ER of the knee
What motion causes a lateral whip
IR of the knee
What whip is most common
Medial
How do you determine the whip
How the heel is positioned (if medial or lateral)
What causes pistoning of the residual limb in the socket (4)
- Suspension inadequate
- Not enough prosthetic socks
- Prosthesis has been put on incorrectly
- Patient has lost weight
