Browsing by Author "Le, David"
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Item Development of a Visualization Tool to Understand Gait(2016-03-23) Patterson, Rita; Le, DavidObjective: The aim of this study was to create a visualization tool that illustrates the motion of specific joint angles during gait cycles. An example of how this tool would be beneficial to understanding gait will be presented by comparing a patient’s joint angle before and after application of Osteopathic manipulative medicine (OMM) and heel lift therapy to improve back pain. Design: A V-gait CAREN system was used to create realistic virtual environments in order to test functional gait and balance in situations that resemble real life. Reflective markers were placed on the head, arms, legs and torso. A 12-camera Motion Analysis System (Motion Analysis Corp., Santa Rosa, CA) tracked reflective markers placed on the body, allowing precise calculation of kinematics, gait parameters, and joint range of motion during movements using the GRAIL (Gait Real-Time Analysis interactive lab) and GOAT (Grail offline analysis tool). A list of 17 joint parameters were compiled and separated into left and right joints on an excel sheet. For each parameter, 50 cycles of gait were analyzed. Sample data from a preliminary subject that has gone through gait analysis via the V-gait CAREN system (Computer Assisted Rehabilitation Environment Network, Motek Medical, The Netherlands) were inputted into the list and each cycle was graphed Results: Graphs for joint parameters up to 50 gaits cycles were automatically generated using the excel tool and proved to be effective for visualizing gait motion. Conclusions: Presentation of one possible way to utilize this tool looks at data from one of our existing studies that compares gait changes of a patient before and after OMM and heel lift therapy to investigate improvements in back pain. Other potential uses for this tool that is not presented would be to visualize the motion of specific joints and compare a subject with a pathologic joint to a subject with a non-pathologic joint. In addition, left and right side joint angles could be compared within one subject. Lastly, pre-treatment and post-treatment analysis can be done for patients using this tool.Item Mechanism of Supination External Rotation Short Oblique Ankle Fractures Revisited: A Cadaveric Study(2016-03-23) Wood, Addison; Fisher, Cara; Nana, Arvind; Payne, Joshua; Le, DavidPURPOSE: The Lauge-Hansen classification system for ankle fractures has been the most commonly used system because it explained mechanism of injury of several common fracture patterns. However, there are limitations to the original Lauge-Hansen experiments and we have chosen to focus our central objective of this study on the biomechanical mechanisms behind stage 1 & 2 supination-external rotation (SER) ankle fractures in a cadaveric model. METHODS: 5 Fresh frozen cadaveric specimens were mounted into a custom made ankle rig with the tibia held rigid using half pins while allowing free movement of the fibula. The foot was secured to a wheel with a torque sensor attached to record examiner external rotational stress application. An electromagnetic tracking system was used to track the motion of the specimen with 6 degrees of freedom at each segment. A control arm was used to hold the foot in dorsiflexion while all other rotations were held in neutral. An ultrasound probe was used to monitor tibiofibular space as the examiner applied a controlled 100N maximal external rotational torque. Specimens were first tested with all ligaments intact prior to incremental resection of the anterior inferior tibiofibular ligament (AITFL) with repeat stress examination after each change. RESULTS: All specimens withstood the normal state testing of up to 100N of external rotational force without any injury. However, 4 out of 5 specimens received short oblique fracture patterns to the distal fibula after partial (75%) or full AITFL resection. Comparison of pre and post radiographs, visual observation via dissection, and live ultrasound video confirmed these results. 3D kinematics were recorded and analyzed as well to determine bone movement and fracture timing and compared to ultrasound video of the tibiofibular space. CONCLUSION: Prior studies have used unmeasured forces, non-physiological ligament strain rates, and poor alignment techniques. We sought to exclude the ligament strain rate and other design issues from our study by performing incremental resection of the AITFL as a synthetic mechanism for stage 1 SER ankle injuries and focusing on the reproducibility of the stage 2 fibula fracture in an SER injury. Our study demonstrated: 1. A 100N external rotational force did not result in an AITFL injury 2. Partial sectioning of the AITFL alongside a 100N external rotational force led to a reproducible oblique distal fibula fracture in a cadaveric ankle model.