PARTIALFOOTAN ILLUSTRATIVE GUIDE
Design & Fabrication for a
Partial Foot Prosthesis that will...
•

Reduce Friction•

Reduce Shearing•

Reduce Pressure•

Restore Propulsion•

Restore Limb Length•

Preserve Residual Limb

Support for Better Life

Introduction

This book is in response to requests from practitioners interested in a comprehensive prosthetic
program to manage partial foot amputations.

Reimbursement Codes

Any reference to reimbursement codes are based on suggestions from practitioners using thesetechniques and are not suggested by Allard USA or validated by any reimbursement agency.

Copyright

This publication is © 2015 Allard USA and may not be copied or reproduced without specificauthorization from Allard USA.

Applicable Amputation Levels

The concepts in this book apply to any partial foot amputation first ray or shorter.

About three-quarters of all PFA involve thetoe(s) and/or disarticulation of the metatarsophalangeal joint.

2

Metatarsophalangeal (MTP)

Transmetatarsal (TMT)

Tarsometatarsal (Lisfranc)

Transtarsal (Chopart)PARTIAL FOOT CHALLENGES
1. Loss of Propulsion

The term ‘windlass’ comes fromsailing where it is the winch mechanism where the rope is wound arounda drum, so in the foot the windlass isthe plantar aponeurosis being woundaround the metatarsal head.
Without the first ray windlass mechanism, the footis considered “apropulsive”

2. Shearing Forces

Normal FootNo Shearing Forces

Normally calf group muscle strength is balanced byfoot lever arm length.

Lever arm is the distance between
the point of application of force andpivot.

Loss of Propulsive
Lever Arm

With amputation, muscles overpower the shortened
lever arm, shearing connective tissue creating calluses.

3OPTIONSFoot Prosthesis or Short AFO

ImmobilizationImmobilization leads
to disuse atrophy.

4A foot prosthesis or short AFO with filler prosthesis
cannot replace the lost propulsive lever arm.

Immobilization can’t help restore the propulsive
lever arm and is proven to induce disuse atrophy.

Carbon Fiber Footplate

Carbon Fiber Footplate
WITH a Lateral Strut

A carbon fiber footplate can only partially lengthen
the propulsive lever arm, still allowing shearing
leading to callus formation.

A footplate with a lateral strut leading into a tibial
tubercle height pretibial shell can minimize or eliminate shearing forces by augmenting the shortened
lever arm.

RESIDUAL FOOT PRESERVATIONManaging Friction

Managing Pressure

Friction can be managed by making sure the socket
isn’t too large and shoes aren’t too big.

Pressure can be managed by making sure the socket
isn’t too small or shoes aren’t too tight.

Residual Foot Preservation........................................................................................

Foot
Preservation
Summary
To optimize residual foot soft
tissue integrity it is important tomake sure it is protected from:• Friction• Pressure• Shearing forces

Carbonfootplate

SAFO

BlueROCKER

Studies have shown destructive forces are distal to the residuum using
BlueROCKER, thereby preserving the residual foot.

5MANAGING LIMB LENGTH
Range of Motion

Calcaneal Angle

dorsiflexion

Nominal ROM at the ankle is 20º
dorsiflexion and 40º plantarflexion.

TMA

With the ankle at neutral, the normal
calcaneal angle is 40º.

LISFRANCAt TMA level amputation, expect 9,5 mm At Lisfranc level, expect 12 mm toto 12,7 mm acquired limb length deficit. 16 mm acquired limb length deficit.

CHOPART

At Chopart level, expect 22 mm to35 mm acquired LLD. Note acquired
bulbous heel associated with ankle
plantarflexion.

Determine leg length discrepancy

Measure limb length from fibular headto floor on both involved and uninvolved
sides to determine acquired LLD.
6Determine if restoring calcaneal angle can resolve
LLD. Have patient stand on end of 1X4 board andlift the other end. Note/document calcaneal angle.

MANAGING LIMB LENGTH
Adjust for leg length discrepancy

NOTE:
A calcaneal angle of 40owill return the ankle toneutral and should resolve
any acquired LLD andeliminate or minimize anacquired bulbous heel.

Wedge anterior aspect of calcaneous to previousmeasurement. If LLD is not fully resolved, it will benecessary to post the heel section of the socket.
See page 8, step 5 for illustration.

GAIT RESTORATION
Restore Propulsion
Data show that at TMA level, the ankle
loses 85% of propulsive power. At Lisfranc
and Chopart, the loss is 100% due to lackof a propulsive lever arm.
Compensations include hip-hiking, trunklean, shorter sound side step length, andincreased trunk torsion to advance theinvolved side limb through space.
Management of any partial foot amputation requires restoration of the propulsive
lever arm.

Tibial tubercle height pre-tibial shell, lateral strut andkinetic return footplate help restore propulsion.
7

PROSTHESIS FABRICATION
1. Cast

2. Positive Model

Cast residual foot. Also cast contralateralfoot so the prosthesis can be built to match.

Make positive model of residual limb.

3. Distal Cushion

4. Mold Socket

Mold 3,2 mm Impression Puff™
(25 Durometer Shore A EVA) for distalcushion.

Mold 3,2 mm black co-polymer for thesocket.

5. Post6.Trim Lines

Post anterior aspect of socket to restore ankle
neutral, and post posterior aspect if there is any
residual LLD (see page 6).
8

Trim anterior aspect of socket at start of filler
prosthesis. Trim posterior aspect as a foot orthosis.

PROSTHESIS FABRICATION
7. Align to BlueROCKER

Align socket to BlueROCKER, trimming toaccommodate lateral strut if necessary.

8. Laminate Layers of Microcell Puff ®

Laminate 6,4 mm layers of Microcell Puff Lite tobuild the filler prosthesis, conforming it to the rocker footplate.

10. Add Interface

Line pretibial shell with SoftKIT, ComfortKIT, orCustom Interface to protect tibial crest.

9. Shape Foot and Socket

Shape to match the length, width and sagittal plane
profile of the contralateral foot.

11. Align Tibial Shell

Align pretibial shell to tibial crest for equal top
to bottom pressure distribution before securing
prosthesis to footplate.

9

SHOE SELECTION & EXERCISES
Shoe Selection
Footwear requirements include adequate
heel/toe height differential, and toe rockersole. A well constructed shoe (firm counterand shank) will produce better results.
Flat-soled shoes (dress, court or deck shoes)
are contraindicated.

BABY SQUATSExercises
These exercises will help the wearer acclimate
to their new environment by learning to takeadvantage of the energy return properties ofthe prosthesis. The importance of doing these
exercises prior to walking cannot be overstated.

Baby squats (heels stay on the ground). Illustrated aresagittal, rotate right and rotate left squats.

10

TRI-PLANAR LUNGES

TRI-PLANAR HIP EXCURSION

Step out, step ahead and cross-step, making sure bothknees are flexed.

Determine excursion distance frontal plane, and thenrotating forward and rotating to the back .

ACKNOWLEDGEMENTS
Robert H. Meier, CO, BOCO whose dedication, contribution, and love of theO&P industry made this illustrative guide possible.
David Scurti, CPO, for his early pioneering in partial foot prosthetic leverarm principles.
Dennis Amtower, CP, for continuous input on partial foot prosthesis fabrication.
Seamus Kennedy, BEng (Mech), CPed, for his expertise in foot biomechanics
relating to the windlass mechanism and loss of propulsion secondary topartial foot amputation.
Ryan Feltman for the high quality professional illustrations.

11®

BlueROCKER is recommended
for all PFA shorter than 1st ray.

For a stable ankle and no otherproximal deficits, ToeOFF may beconsidered for 1st ray amputations.

AFO Selection
ToeOFF 2.0 With D-Ring

ToeOFF 2.0 No D-Ring

BlueROCKER

Size

Item No. Left

Item No. Right

Item No. Left

Item No. Right

Item No. Left

Item No. Right

X-Small

28922 1010

28922 2010

28920 1010

28920 2010

28405 1010

28405 2010

Small

28922 1011

28922 2011

28920 1011

28920 2011

28405 1011

28405 2011

Medium28922 1012

28922 2012

28920 1012

28920 2012

28405 1012

28405 2012

Large

28922 1013

28922 2013

28920 1013

28920 2013

28405 1013

28405 2013

X-Large

28922 1014

28922 2014

28920 1014

28920 2014

28405 1014

28405 2014

Size

Footplate Length

HeightX-Small

210 mm

360 mmSmall

230 mm

380 mmMedium

245 mm

405 mmLarge

270 mm

430 mm

X-Large

285 mmBR = 430 mm
2.0 = 450 mm

Interface Selection
ToeOFF 2.0
Size

BlueROCKER

SoftKIT

ComfortKITSize

SoftKIT

ComfortKIT

X-Small

28750 0010

28751 0010

Small

28750 0011

28751 0011

X-Small

28390 0010

28398 0010

Small

28390 0011

Medium

28750 0012

28398 0011

28751 0012

Medium28390 0012

28398 0012

Large
X-Large

28750 0013

28751 0013

Large/X-Large

28390 0013

28398 0013

28750 0014

28751 0014

Support For Better Life!