Modifications and upper extremity orthotics for the Lofstrand crutch

crutch;orthosis;orthoses;orthotic;lofstrand;forearm;wrist;piston;accumulator;ergonomic

Farooq, Deen S ; Hsiao-Wecksler ; Elizabeth T.

关键词: crutch;    orthosis;    orthoses;    orthotic;    lofstrand;    forearm;    wrist;    piston;    accumulator;    ergonomic;   

Others  :  https://www.ideals.illinois.edu/bitstream/handle/2142/88952/FAROOQ-THESIS-2015.pdf?sequence=1&isAllowed=y

美国|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

According to the latest National Institute on Disability and Rehabilitation Research (NIDRR) Mobility Device Report, there are an estimated 566,000 persons who use crutches in the US. During Lofstrand crutch mobility, irregular loads are placed upon the upper extremities during quadrupedal gait. During self-load bearing while walking with Lofstrand crutches, the arms can experience periodic loads every 1 s of up to 50% of body weight for durations as short as 340 ms. Excessive loads and motion of the wrist increase chances for carpal tunnel syndrome. Lofstrand crutch users would clearly benefit by having these upper extremity demands reallocated or supported by an orthosis to allow for longer-term ambulation, reduction in pain, and injury avoidance. This thesis contains two studies: the design of a passive orthosis for Lofstrand crutch gait, and the use of a pneumatic pump as an energy harvesting device. An orthotic attachment for the Lofstrand crutch was developed, in order to reduce wrist extension and redirect loads from the carpal tunnel region on the palm and toward the adductor pollicis. Pressure sensors were used at the handle of the crutch to locate and measure loads, while motion capture was used to calculate joint angles. Results show a decrease in the average force and mean pressure across a Lofstrand crutch handle when using the orthosis, although peak palmar pressures may be greater with the orthosis. Palmar load displacement toward the adductor pollicis was achieved.There is motivation to extend this work by using soft robotic technology, which will be powered pneumatically. Therefore, a preliminary design for a pneumatic harvesting device that can accumulate pressure throughout the gait cycle was created and assessed.The harvesting device was a piston attached to the tip of the crutch. When compressed, the device stores the pneumatic energy into an accumulator. Data were collected using a pressure transducer. A mathematical model of pressure in the accumulator was developed in order to predict accumulated pressure as a function of effective volume of the piston and dead volume in the system. The model simulation results were compared to experimental values and ranged from 3.79-15.53 percent error. A second custom piston design to achieve higher stroke volume is also presented.