Prosthetic Gait Deviations

Question 1

What are the 2 most common causes of excessive knee extension during intial contact to loading response?

Answer 1

1. Too soft cushioned heel = allows the prosthetic foot to PF too quickly which leads to knee extension
2. Posteriorly displaced socket or anteriorly set prosthetic foot = sets the knee more posterior to the foot during intial contact to loading response leading to an extensor moment at the knee

Question 2

What are the 2 most common causes of knee instability during intial contact to loading response?

Answer 2

1. Too hard cushioned heel = does not allow for adequate PF of the prosthetic foot; patient compensates by flexing the knee to get the foot down on the floor
2. Anteriorly displaced socket or posteriorly set prosthetic foot = sets the knee more anterior to the foot during intial contact to loading response leading to a flexor moment at the knee

Question 3

What are the 2 most common causes of a wide based gait during midstance?

Answer 3

1. Outset foot = patient loses medial support when the foot is set to laterally
2. Medially leaning pylon = top of the pylon is displaced more medial than the bottom which results in medial instability