Ravi Chacko CEOChase McCaleb CFO
Walker Plash CMOPerry Yin CTO
George Zhou CRO
ACL Injury Background…100,000 -200,000 ruptured
per year1
60,000-75,000 ACL reconstructions annually2
Costs range from $20-50k without insurance, $800-3,000 with
150x more likely to re-injure3
1. Mayo Clinic Online2. JD Hubbell, MD; E Schwartz, MD; http://emedicine.medscape.com/article/89442-overview3. Dunn et al 2004
Reasons for ACL Tears…Planting and cuttingStraight-knee landings
Causing…Hyperextention of the
kneeExcessive inward
rotation
MarketCDC estimates 7.2 million high school
athletes in the U.S.1
Approximately 4 million professional athletes.
Affects anyone involved in:VolleyballBasketballSoccerFootballGymnasticsAnd more
1. CDC: MMWR; September 29, 2006 / 55(38);1037-1040; http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5538a1.htm
Known Risk FactorsPhysiological FactorsHormones, Sex, Leg Dominance, Joint
Laxity/Recurvation
Behavioral FactorsLanding/Jumping
Torso position and resulting stresses on knee
Toe to heel shock absorptionSide Cut
Quad and Hamstring firing patterns
Risk Factors- ZebisMette K. Zebis
(7/09)Found that a
difference in Vastus Lateralis and Semitendinosus firing 10ms before a side cut led to a significantly increased chance for ACL rupture.
Risk Factors - LESSLindsay J. DiStefano (2009)Used Landing Error Scoring System (LESS)
before and after training to show that landing errors can be improved with training.
Current prototype can capture knee flexion and displacement
May Prototype will include a hip component that will capture trunk flexion
ComponentsEMG
Vastus Lateralis Semitendinosus
2 IMU 6DOF Sensors3 Gyroscopes3 Accelerometers
4 Pressure SensorsAmplifier
NIDAQ & Arduinos
Force Sensor CaptureOriginal Design 2 sensors
Heel and ToeAnkle pronation and impact time
1st Prototype 4 Sensors 1st and 5th metatarsal, heel and big toe Time of impact, ankle and foot pronation
Force Sensor AnalysisVertical Jump Test (x2)
Toe (red) is used primarily during takeoff1st (cyan) and 5th metatarsal (green) are
used primarily during landing Heel (blue) is kept off the ground
EMG CaptureEKG electrodes placed
at the VL and STGrounded at the
abdomenSystem contains a
circuit for a DC offset so we can view both positive and negative values
EMG AnalysisPurpose: to
capture the difference in average activity (% of max) in the 10 ms prior to cut.
Method:Sync Filter ThresholdRMS
Motion CaptureInertial Measurement Units (IMU)
consist of 4 perpendicular accelerometers and 4 perpendicular gyroscopes
IMUs attached to brace at the calf and thigh
Record linear acceleration and rotational velocity, each in 3 dimensions at each point
Motion Capture Analysis
Motion Capture Analysis
Side Cut
Side Cut
Future PlansFinal PrototypeLightweight and wirelessFree movement
This SemesterStay tethered, but clean up wires to increase
mobilityExpand to include multiple testsMultiple test subjects
Development TimelineInterpret data
collected from gyros/accelerometers
Increase mobilityImprove EMG
analysisConnect mechanical
to bioelectric dataCreate GUI for data
collection and analysis
Future Business PlanPhase II: Research and Development
Distribute to athletic teams for data collectionProve that we can actually predict risk factors
Phase III: Initial ReleaseTarget athletic teams, gyms, and physical
therapists.Projected cost of use:
$250 initial startup fee $50 per athlete per analysis
Phase IV: Review and ExpansionUltimately target home users
Thank youKeith YeagerAaron KyleProf. Gordana Vunjak-NovakovicProf. Elizabeth HillmanProf. Paul Sadja
Project AdvisorMatthew Bouchard & Ick BhumiratanaLauren GrosbergJim Gossett
Associate Athletics Director for Sports MedicinePaige Plash
Physical Therapist, COO Encore Rehabilitation
Questions?
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