Recovery Track(er)1 Biomedical Engineering Senior Design Project Levy Amar, Pravin Chottera, Kate Millington, Pooja Shaw

Recovery Track(er) 2 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.

Recovery Track(er) 3 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.

Recovery Track(er) 4 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 Tendon Rupture Sudden onset: a ‘pop’ Only treatable by surgery requiring 6 to 12 month recovery Joint- Arthritis Osteoarthritis 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

Recovery Track(er) 5 Demographics Who is the User? Patients recovering from ankle surgery or serious injury Use outside the clinic in the patient’s home Results sent to attending physician or physical therapist Who is the Customer? Hospitals or Physical Therapist Offices Loaned to patients as needed Used to track individual patient progress Can also be used to evaluate treatment and recovery methods User & Customer

Recovery Track(er) 6 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

Recovery Track(er) 7 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 , regarding the electrode lead wires and patient cables used in an orthopedic diagnostic device.

Recovery Track(er) 8 Project Design Ideas Parts 1, 2, & 3 Part 1: Insole Acquiring the Data Part 2: Data Acquisition Gathering and Storing the Data Part 3: Signal Analysis/ Data Output Display 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:

Recovery Track(er) 9 Part 1: Insole Acquiring 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?

Recovery Track(er) 10 Part 1: Insole Acquiring the Data 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?

Recovery Track(er) 11 Part 1: Insole Acquiring the Data 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

Recovery Track(er) 12 Part 1: Insole Acquiring the Data

Recovery Track(er) 13 1) Circuit Board Our 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? Part 2: Data Acquisition Gathering and Storing the Data

Recovery Track(er) 14 Part 2: Data Acquisition Gathering and Storing the Data 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?

Recovery Track(er) 15 Part 2: Data Acquisition Gathering and Storing the Data 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?

Recovery Track(er) 16 Part 2: Data Acquisition Gathering and Storing the Data Circuit board can either go into pouch on shoe or an ankle strap

Recovery Track(er) 17 Part 3: Signal Analysis/ Data Output Display of Data in an Easily Accessible Interface 1) Complete Data Set Graphical 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)

Recovery Track(er) 18 2) Differential Graphical 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? Part 3: Signal Analysis/ Data Output Display of Data in an Easily Accessible Interface

Recovery Track(er) 19 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 Part 3: Signal Analysis/ Data Output Display of Data in an Easily Accessible Interface Output is % improvement from last use- progress back to normal Either: Poor, Fair, or Good Progress % Improvement Good Fair Poor

Recovery Track(er) 20 Part 3: Signal Analysis/ Data Output Display of Data in an Easily Accessible Interface % Improvement Good Fair Poor

Recovery Track(er) 21 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

Recovery Track(er) 22 Acknowledgements Our group would like to thank: Professor Hillman Professor Sajda Professor Kymissis