Development of an Ergonomic Manual Wheelchair Pushrim- Phase II

Principal Investigator: Ronald M. Boninger, MBA

Co-Investigators: Michael L. Boninger, MD; Rory A. Cooper, PhD

2005-2007

People in wheelchairs push on their handrims an average of 2500 times a day and 17,500 times a week as they engage in activities of daily living. The repetitive stress of wheelchair propulsion results in an extraordinarily high incidence of upper extremity pain and injury (as high as 70%) among manual wheelchair users. One alterable source of this problem is the poor design of standard round-tube handrims: they do not provide an ergonomic grip for the hand, they ignore differences in upper-extremity function and they ignore the threat of secondary injury to the
upper-extremities. The research proposed here attacks this problem head-on by examining the potential for ergonomic innovations in handrim design to meaningfully reduce the incidence of upper-extremity pain and injury among manual wheelchair users. Phase I research provided initial verification of this potential: after a two week trial use period, subjects indicated highly favorable evaluations of the Natural-Fit, and analyses of propulsion biomechanics indicated that the Natural-Fit resulted in more efficient wheelchair propulsion than a standard rim.
 

In Phase II, we developed and tested the effectiveness of ergonomic handrim designs that addresses differences in upper-extremity function (paraplegia vs. tetraplegia) and differences between men, women and children. The goals of this project were to create size options to better customize the fit to the hand, test coating alternatives to optimize effectiveness and durability, design and test a handrim tailored to the propulsion style and hand function of people with tetraplegia, and conduct a trial that incorporates a long term trial of the handrims. Different size handrim have been developed and focus groups have been conducted to collect end user feedback on the different sizes and coating options. In addition, durability testing has been completed on three different coating surfaces. The 4 month in home trial that incorporates a long term investigation of the impact of the new ergonomic handrim is ongoing. By offering the potential to improve the biomechanics of wheelchair propulsion and reduce stress on the shoulders and wrists of wheelchair users, the Natural-Fit Handrim may help to reduce the pain and injury that is so common among manual wheelchair users, it may help to extend the time that one can remain in a manual wheelchair, and it may help to reduce medical costs associated with secondary injuries such as CTS and shoulder injury. As evidence continues to accumulate that directly links wheelchair propulsion biomechanics to wrist and shoulder pain and injury, the potential impact may be profound. As clinicians and scientists begin to determine how the wheelchair, its component parts, and one’s propulsion style contribute to upper extremity injury, it will facilitate the ability to design, select, fit, and even train them in proper propulsion techniques in a way that will help to reduce the likelihood of developing a secondary disability.