Document

Report
Hands Free Hydro Cast – Optimising
Trans-femoral Socket Design and
Maximising Rehabilitation Potential
Buis AWP, McGarry A, Kamyab M, Murray KD, Hillman S
Biomedical Engineering, University of Strathclyde, Glasgow, UK
Introduction
•
•
•
•
•
Statement of problem (Why)
Implementation of a “good” fit
Methodology (What & How)
Results
conclusion
Statement of problem
•
The purpose of a socket is to provide a mechanical connection
between the skeleton and the rigid structure of the prosthesis.
•
The dominating concepts are the Quad and Ischial cont.
•
•
•
How stabilising are those sockets?
Are they reproducible?
Can we do better?
Implementation of a “good” fit
•
Socket fit criteria:
o As “stiff” as possible coupling
o No tissue damage
o Minimum discomfort
Implementation tools;
o Surface matching
o Volume matching
•
Is it possible to distribute the load to the different transmission elements in a controlled
way?
•
Yes, if the force flow distributes itself proportionally to the stiffness of the available path!
Implementation of a “good” fit
Rubber Block
Metal Block
Rubber Block
“Let nature deform the soft tissues in such a way that the
stiffest path principle is achieved”
Methodology
•
Copy of the existing Ischial containment socket.
•
Pressure cast socket according the Hydro cast principle.
Methodology
(work packages)
1.
Dynamic interface pressure
2.
Femoral stability
3.
User performance outcome measures
•
•
(ideally shear)
Kinetic (forces)
Kinematic (position in space and time)
Methodology
•
Dynamic interface pressure
•
Validated Tekscan™ pressure
measurement system
Methodology
•
Femoral stability
Methodology
•
User performance outcome measures
•
•
Kinetic (forces)
Kinematic (position in space and time)
Results
•
A
Dynamic interface pressure
M
P
L
Ischial
containment
Hydro
Sensor
Results
Ultra sound
Anterior
Medial
X section
socket
Video
Results
Lateral
Lateral
A
P
Medial
Hydro Cast
P
A
Medial
Ischial Containment
Results
•
User performance outcome measures
Summary
•
Speed slightly higher with the old socket, but it was noted that
the
subject’s speed increased as she became more accustomed to the new
socket.
•
Stride length slightly longer with the old socket, effected via increased
step length bilaterally.
•
•
•
Cadence and double support time much the same for both conditions.
Single support time on the right a little decreased with the new socket.
Clear differences between pistoning and gapping were observed.
Indicating that the Hydro concept is more stable.
Conclusion
•
•
•
•
No significant pressure distribution differences.
Shear should be investigated!
No significant Kinetic and kinematic differences.
Significant stability differences in direction,
pistoning and gapping in favour of the Hydro concept
prosthesis.
Thank you!

similar documents