The Mechanical Knee Reinvented. - AOPA

Introducing the LegWorks All-Terrain Knee

November 22nd, 2016Brandon Burke, Co-Founder & Director of Partnership Development

The Mechanical Knee – Reinvented.

LegWorks is a Canadian company, with offices in Toronto and San Francisco.

We aim to provide the stability and safety every amputee deserves with the function and speed to allow every amputee to excel.

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Brandon BurkeCo-Founder & Director of

Partnerships Development

[email protected]

1. Introduction to the All-Terrain Knee2. User testimonials3. Benefits of the All-Terrain Knee4. How to fit and adjust the All-Terrain Knee5. User training for the All-Terrain Knee

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Tech Specs

150 kg (330 lbs)

Our patented AutoLock Technology

providing unparalleled stability with every step

• Multi axial design

• Unlocks with weight on the toe followed by a hip flexion moment

• Positive locking mechanism that locks upon reaching full extension

Single AxisManual Locking

4-barPolycentric

All-Terrain Knee with AutoLock

Technology

6-barPolycentric

6-bar during StanceFlexion



Patients walked

7-15% faster on average

Patients

fell 30x less on average

Patients expended

40% less energy on average

95%preference

Our Variable Cadence Controller

providing smooth walking at multiple speeds

• Allows for variable cadence

• Alleviates excessive heel-rise

• Alleviates terminal impact


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Meet Brian, bilateral patient

All-Terrain Knee user for 3 years

Meet Gravial, hip disartic patient

on his first day on the All-Terrain Knee, August 2016


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1. Confidence in stability

• Locks upon full extension, which provides great early stance-phase stability

• Prevents unwanted initiations of swing-phase because a toe-load is needed prior to hip flexion

2. Promotes natural gait

• No need to use hip extensors to pull heel into the ground

• Makes the user bear weight on their prosthesis side through late stance-phase (alleviating many prominent gait deviations, such as hip-hiking and sound-side vaulting)

3. Energy Efficiency Savings

• 40% energy efficiency savings compared to friction braking knees due to a more normal gait pattern and increased stability

Top Three Benefits of the AutoLock Technology

Allows for multiple walking speeds/variable cadence

• Allows for multiple walking speeds via a frictional resistance profile and spring damping combination

• Designed to perform similar to the resistance profile of a hydraulic unit

Top Benefits of the Variable Cadence Controller

Promotes a natural and smooth gait

• Robust design that allows for multiple walking speeds by alleviating excessive heel-rise and dampening terminal impact

How It Stacks Up Against The Total Knee 2000

All-Terrain Knee TK 2000

Durability 150kg (330 lbs) weight ratingAND waterproof!

100kg (220 lbs) weight rating

Stance-Phase Controller Comparison

• Locks upon extension• Tighter window that allows for

swing-phase initiation• Requires sequential toe-load

then hip-flexion• Promotes natural gait pattern

with required toe-load

• Geometric “lock” upon heel-strike

• Buckling of knee possible in non-ideal gait conditions: carrying something, walking down a hill, turning around, etc.

Swing-PhaseController Comparison

• Variable Cadence Controller -Patent pending mechanism developed by LegWorks to provide a similar resistance profile to that of a hydraulic knee

• Alleviates excessive heel-rise and dampens terminal impact in a robust, environmentally resistant design

• 3-phase hydraulic


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• The All-Terrain Knee can only be unlocked and moved into a flexed position when on a complete prosthesis.

• The cover also acts as a lock release for the AutoLock mode.

How to Unlock the All-Terrain Knee

How to unlock the All-Terrain Knee by hand

• 20mm recommended posterior offset of knee axis from alignment reference line

• Shifting the knee posterior increases BOTH the ease of initiating swing-phase (knee unlocking) and the geometric stability of the knee

Sagittal Plane Alignment

Further posterior shifts of the knee may be done for those struggling to unlock the knee

Cover Removal

When adjusting alignment of the prosthesis, please remove the cover to access the setscrews.

• Ensure the proper contact point for the socket and knee, which is the pylon adaptor.

• A knee setup with an improper contact point may cause a failure of the knee in the event of a fall causing the knee to go into max flexion

Flexion Stop

Socket resting on molded pylon adaptor

Extension assist mechanism

Improper contact point Proper contact point

• Adjustments that can be made:

- If the patient experiences excessive terminal impact - tighten the friction mechanism (compressing the disc springs) to increase the frictional resistance that slows the knee’s rotation

- If the All-Terrain Knee’s friction mechanism has been tightened and is not reaching full extension due to excessive resistance - loosen the friction mechanism to allow for the knee to safely reach full extension

• Factory Setting: 1 ½ turn loose from full compression of disc springs.

- Do not loosen the friction mechanism more than factory setting, as the friction mechanism may disconnect

Friction Mechanism Adjustment

- + Friction Mechanism Threaded Cap

Friction Mechanism Cap

• The stronger the extension assist spring is, the greater extension assist bias

• If the patient is high-activity and is waiting on the knee to reach full extension try using the high stiffness spring (red)

• If the patient is struggling to smoothly initiate swing-phase and having difficulty getting the knee to reach full extension, consider swapping to the high stiffness extension assist spring (red)

Extension Assist Adjustment

• If the lock is not engaging, or there is too much movement, tighten the lock spring set screw

• If the knee is noisy in early swing, or difficult to unlock, loosen the lock spring set screw in 1/8

• Make adjustments in 1/8 turn increments

Lock Spring Adjustment

Factory Setting: Set screw protruded by ¼ turnMax Looseness: ¾ turn protruded


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• The AutoLock Technology promotes a more natural gait pattern and requires toe-loading followed by hip-flexion to initiate swing-phase.

• Some users may struggle initially due to gait deviations from previous devices, or a limited ability to bear weight for new amputees.

• Adjustment periods generally happen pretty quickly, with most patients walking well within a two week period.

Gait Training Overview

• Teach the user how the knee works:

- The knee locks upon reaching full extension.

- It unlocks by toe-loading in late stance-phase, followed by hip flexion moment to initiate swing-phase.

• Practice unlocking the knee statically before attempting

• Position prosthesis leg behind and sound leg forward. Balance weight between the two and practice going from toe-loading to heel-strike.

Prior to Having the User Walk

Proper Toe-LoadingHip-Hiking/ Premature Unweighting

• Hip-hiking, sound-side vaulting, and weight shifting (towards sound side)

- It is important to teach the user that when this occurs, the knee is giving bio-feedback that the patient unweighted their prosthesis side prior to hip flexion, and that they need to keep their weight down through hip flexion to take a better step.

• Circumducting

- Have the user practice swinging the leg straight through (envisioning the kicking of a football is often very helpful for this)

• Uneven stride lengths, too short of a sound side

- Encourage the user to weight bear on their prosthesis side longer and take a bigger step on their sound side (develop trust in the knee)

• Passive hip extensors

- Have the user fire their core muscles, including their glutes to create more rigid biomechanics of the body and a better, more energy efficient utilization of their prosthesis

Troubleshooting with Your Patient

• Method 1“Toe-tap” -Place your prosthesis slightly behind you sound leg, load the toe and flex your hip to initiate swing-phase. Once in swing-phase, use your sound leg to lower yourself onto your seat.

How to Sit

• Method 2 “Cover Release” – Unweight prosthesis side, lift your prosthesis forward, sit down using your sound leg, and then use the cover release feature to unlock and bend the knee. Toe-Tap Cover Release

• Use the twist knob on the front of the All-Terrain Knee to switch between AutoLock Mode and Manual Lock Modes

Unlocked (AutoLock Mode)

Locked (Manual Lock Mode)

• Twist knob can be engaged or disengaged when in full extension or when flexed, and it will lock the next time it reaches full extension.

Using the Manual Lock

Marketing Flyer Quick Fitting Guide for the All-Terrain Knee

Instructions for Use

Instructional Video

Our Handouts

Questions?

Brandon BurkeCo-Founder & Director of Partnerships Development

[email protected]

www.LegWorks.com

The Mechanical Knee Reinvented. - AOPA

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