recovery track(er)1 biomedical engineering senior design project levy amar, pravin chottera, kate...

Recovery Track(er) 1

Recovery Track(er)

Biomedical EngineeringSenior Design ProjectLevy Amar, Pravin Chottera, Kate Millington, Pooja Shaw


Design Problem The ankle bears the most weight per unit area than any

other place in the body. Ankle injury, specifically ankle sprains, are the most

prevalent injury during recreational activity.

Despite prevalence of injury, and thus treatment, there are few quantitative ways to monitor the recovery process or gauge the efficacy of treatment.

Currently, monitoring of patient recovery requires the patient to come into a physical therapist on a regular basis and perform a series of weight baring and gait analysis test. These tests only estimate normal function and do not provide

an in situ measure.

Furthermore, traveling to the clinic on a regular enough basis is inconvenient for the patient. Patients frequently miss appointments if they are required to

go on a regular basis for a long period of time, impeding their recovery process.


Design Brief We propose to build a device which will help patients

track their rehabilitation process after ankle surgery or series injury. The device will be small enough to be comfortably worn in

the user's shoe without altering normal gait or causing further injury.

It will collect information about force distribution both spatially and temporally.

The collected information will be relayed back to a central computer where the collected data will be compared to normal values. (i.e. the values from the ‘healthy’ leg) The original force data, as well as the quantitative

comparison, will be displayed in an easily accessible interface.

This device can be sent home with patients receiving physical therapy and allow them to collect data at their convenience in their own home. They can then send this data to their medical specialist to be evaluated.


Four Modalities of Ankle Injury

Ligament- Ankle Sprains 75% of all ankle injuries Most common recreational injury $2 billion annually in the U.S.(AAOS)

Bone- Ankle Fracture Caused by rolling ankle inward or outward Ranges from avulsion to shattering Treated by immobilization or surgery depending on

the severity of the fracture.

Tendon- Achilles TendonRupture Sudden onset: a ‘pop’ Only treatable by surgery requiring 6 to 12 month

recovery

Joint- ArthritisOsteoarthritis Wearing away of cartilage lining joint Due to prior joint injury or ageing

Rheumatoid Arthritis Inflammation of the joint Surgically treated by fusion, clearing, or replacement

Demographics

JOINT

BONE

TENDON

LIGAMENT


Demographics

Who is the User?Patients recovering from ankle surgery or serious injury

Use outside the clinic in the patient’s homeResults sent to attending physician or physical

therapist

Who is the Customer?Hospitals or Physical Therapist

OfficesLoaned to patients as neededUsed to track individual patient progressCan also be used to evaluate treatment and recovery

methods

User & Customer


Competing Products

1) TekScan•In office use•One time output for diagnosis•No tracking of data

2) Nike+ iPod Sport Pack

•Wirelessly transmits music from iPod to Nike shoe•Audio signal only•Non-medical use•Circuit board on Recovery Track(er) is in the same location as the receiver on the Sport Pack


Constraints and Specifications

Cost Control

Consistency Comfort

To be widely accessible and usable the device must be inexpensive to produce and readably useable with little to no training

Device must provide accurate data on the recovery process without causing further injury to the patient, impeding their recovery, or altering normal function. Since osteoarthritis is a major cause of ankle injury, it is important that our device be comfortable and accessible to the elderly population.

Our device must also be in compliance with FDA regulations specified under Section 888.1500, regarding the electrode lead wires and patient cables used in an orthopedic diagnostic device.


Project Design IdeasParts 1, 2, & 3

Part 1: Insole

Acquiring the Data

Part 2: Data AcquisitionGathering and Storing the Data

Part 3: Signal Analysis/ Data OutputDisplay of Data in an Easily Accessible Interface

Send Parts 1&2 home with the patient:

Send the data in to physical therapists at regular interval for Part 3- evaluation of progress:


Part 1: InsoleAcquiring the Data

1) Fixed Pressure Sensors A flexible insole covered in

commercially available standard pressure sensors

• Sanitation? Different disposable covers? Individual patient sensor boards?

• Different Sizes? Limited by sensor size or cost?

• How many sensors do we need? Statistical and physical significance?



2) Sensor Envelope

Disposable insole ‘envelops’ into which individual sensors are placed.

• Allows for easy sanitation and size differences.

• Requires training of user. Too complicated to put together?

• Will sensors be secure enough to record accurate data? How will we secure in pockets?

• How will we wire the sensors to allow easy insertion without tangling?



3) Piezoelectric Film

A texurized flexible insole overlaid with PVDF (a piezoelectric film which acts as a force sensor and can detect strain with a linear output)

• Customizable to physiological sites and sizes.

• Will texturized sole interfere with healing or natural gait?

• How will we read output?

• Capacitive interference from wiring? Is there a finite amount of possible data collection due to time resolution or PVDF properties.

• No precedent of use


1) Circuit BoardOur Black Box

• How many sensors can we put in one microprocessor?

• What speed etc are we going to need?

• How big of a memory chip?

• Power Source? Batteries?

• How will we upload to the computer? UBS? Bluetooth? Will this add weight or bulk? Cost?




2) Ankle or Belt Strap

“Black Box” attaches around ankle or clips to belt

• Ankle allows direct wiring to sensors. Belt would need wireless?

• Shape? Weight?

• Safety?

• If wired - how could we do it cleanly

• If wireless - how would we do it? Where could we upload it to?



3) Pouch

The “black box” is in a pouch that can be attached to the shoelaces of the shoe

• Allows direct wiring to sensors. How can we wire it cleanly?

• Could also be wireless.

• Shape? Weight? Will adding too much to foot cause strain?

• Safety?

• Is pouch enough to protect circuit inside?

• How will memory and power source be accessed?



Circuit board can either go into pouch on shoe or an ankle strap



1) Complete Data SetGraphical output of entire data

set

• Too much information to be useful? Will depend on intended user

•Can show everything collected and leave bias to the interpreter.

•Leaves user to do all of analysis and qualitative tracking of recovery by using side by side comparisons to normal

• Could have option for differential (see next idea)


2) DifferentialGraphical output of differential data set

• Only shows areas different from ‘normal’ image

• Distills data into important areas for further investigation.

• Over simplification?

• Does this take into account interactions between different parts of the foot

• How would we set the threshold for significant differential?



3) Numerical Output

• All analysis done behind the scenes.

• Requires little training to use - user doesn’t need to know anything about analysis only gets answer they need.

• Too little information?

• Too much behind the scenes opens up program for generalization induced mistakes


Output is % improvement from last use- progress back to normal

Either: Poor, Fair, or Good Progress

% Improvement

Good Fair Poor



% Improvement

Good Fair Poor


Summary

Device to enable clinicians to track recovery of post ankle surgery patients using in situ quantifiable data

Comfortable and lightweight in order to ensure accessibility and encourage frequent use and ‘normal’ data output

Consists of a patient take-home piece:(1)force sensing insole, (2) data acquisition box,

and an in-office analysis piece:

(3) easy to use data analysis and display software


Acknowledgements

Our group would like to thank:

Professor HillmanProfessor Sajda

Professor Kymissis

recovery track(er)1 biomedical engineering senior design project levy amar, pravin chottera, kate...

Documents

ankle surgery

patient recovery

recovery process

design problemthe ankle

series injury

aaosbone ankle fracturecaused

prevalent injury

prevalence of injury