Tacking the challenges to professional education arising from the pace of technological development

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Tacking the challenges to professional education
arising from the pace of technological
development and the need for lifelong
learning Sub-project Computer-Aided Learning for
Prosthetic Designs Ming ZHANG, Arthur FT Mak,
Hok Sum MAN Jockey Club Rehabilitation
Engineering Centre The Hong Kong Polytechnic
University Yubo FAN, Fang PU, Wentao JIANG
Sichuan University, China PolyU IGARD Project
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Objective

• To develop a computer-aided teaching/learning
  package which can help students to better
  understand the design of a lower-limb prosthesis
• BSc in Prosthetics Orthotics
• in Health Technology

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Background

• Lower-limb prosthesis
• modular components
• Socket
• human-device interface

• Prosthetic socket are important
• .Functional Comfort requirements
• Custom-made for individuals

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Background

• The shape of a prosthetic socket should be
  different from residual limb shape

• Apply forces on Pressure Tolerant Areas to hold
  prosthesis firmly on the residual limb.

• Relief pressures on Pressure Intolerant Area of
  residual limb to prevent pain or injure.

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Major Concerns for Socket Design

• Shape modification
• Based on the Residual limb shape
• How deep of modification should be applied?

• Prosthetic socket modification depends on
  individual experience.
• How to assess/validate the design?
• What is the rationale behind the design?

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Present Problem of Socket validation

• Validation of design socket shape is expansive
  and time consuming.

• Check socket should be made to validate the
  designed socket shape.

• Mill the shape with CAM system and model the
  check socket with thermoplastic. (Material Cost
  800 for each trial.)

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• Research showed that the load distribution
  between socket and residual limb is critical for
  comfort and functions
• Shall can develop something to predict the
  interaction between socket and limb during
  walking for a designed socket before fabricated?
  It can

• Save time
• Save materials
• Reduce errors
• Better understanding

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Methods Develop Prosthetic Socket Assessment
System (PSAS) Based on Computational
Modeling (Finite Element Methods) To predict the
load distribution on socket
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Finite Element (FE) Analysis
1.Residual limb shape captured from traditional
CAD System
Negative cast with plaster bandage
Scanning Residual limb shape with Biosculptor
Digitized Residual limb shape
Residual limb
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Finite Element (FE) Analysis
2. Designed socket shape using CAD System
Digitized Residual limb shape
Designed Socket shape file
Modified residual Limb model in CAD System
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Finite Element (FE) Analysis
3.Soft tissue thickness and stiffness to predict
the bone shape and position
TUPS was used to determined the soft tissue
thickness and stiffness
The mechanical properties were saved in PSAS to
predict the bone shape
Several landmarks on residual limb were selected
to determined those mechanical properties
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Finite Element (FE) Analysis of PSAS
Designed Socket shape
Soft tissue thickness and stiffness on residual
limb
Residual limb shape captured from traditional CAD
System
Hard tissue determination
PSAS
Select loading case
FE model
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Finite Element (FE) Analysis
After predicting force distributions on residual
limb in different loading cases, PSAS shows
weather or not the designed socket is suitable
for the patient in different ways.
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Report

• Different Regions of the designed socket may be
  selected manually to show the pressure variations
  during stance phase.
• Full report of predicted pressure variation is
  given automatically.

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Report

• FE models can be browsed into single window to
  compare the pressure variation during walking.

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Summary This project developed a CAT platform
which allows students to evaluate their socket
design before socket is manufactured to
understand the rationale behind the socket
modification.