Design and evaluation of a laboratory-based wheelchair castor testing protocol using community data

Identifying risk factors for wheelchair damage, part failure, and adverse consequences to the user

No tools or technologies exist to inform data-driven inspection schedules for wheelchairs. To develop such a schedule, this study identifies risk factors linked with manual wheelchair damage, part failures, and consequences and evaluates preferences for a new wheelchair servicing technology. A mixed methods study was performed with manual wheelchair users at The Ohio State University Martha Morehouse Clinic. Demographic data, wheelchair information, failure counts, and consequences suffered by the user were collected using surveys. Wheelchair usage was collected for a month using a sensor. A servicing smartphone app that connects with the sensor was demonstrated as a new servicing technology, and participant preferences were recorded. Thirty participants completed the survey testing procedures. Twenty-three collected usage data and eighteen collected it for over a week. At least 215 wheelchair part failures with an average of 13.4 ± 14.8 self-reported part failures and 4.7 ± 4.8 high-risk failures occurred in 12 months before the first study visit. Two weeks of collected data from 18 participants showed that normalised road shocks, age, and weight were associated with the condition of wheels and frames, as well as self-reported caster failures. Participants responded with a favourable preference for the new wheelchair servicing technology, with more than half of them interested in buying and using it. Risk factors like road shocks and user's age and weight are associated with part damage towards failures and self-reported failures that risk injury. These factors can be modelled to develop and test the efficacy of wheelchair inspection schedules.

Wheelchair Servicing for Older Adults: Cross-Sectional Study

Background

Wheelchairs are assistive mobility devices known to experience frequent part failures and breakdowns within 6 months of regular use. No tools or technologies exist to monitor the wheelchairs' condition or usage and inform stakeholders and users regarding when or how often they need to undergo servicing to avoid critical part failure.

Objective

We aimed to test the association between wheelchair usage and manual wheelchair damage, part failures, and consequences for older wheelchair users and evaluate their preferences for a new wheelchair servicing technology.

Methods

A cross-sectional study was performed with older manual wheelchair users atInstituto Nacional de Geriatría in Mexico. Demographic data, wheelchair information, failure counts, and preferences for new technology (sensor and smartphone app for servicing) were collected using surveys. Road shocks experienced by the wheelchair were collected for a week using a sensor.

Results

Ten participants (mean [SD] age, 78.8 [11.8] y; 8 female and 2 male) participated. Seven experienced an average (SD) of 2.86 (1.36) self-reported part failures. Road shocks correlated with self-reported loose brake failures (r(8)=0.58, P=.09), the damaged condition of tires (r(8)=0.61, P=.1), and the damaged condition of brakes (r(8)=0.58, P=.099). No consequences were reported. Part failures increased as self-maintenance occurrences increased (r(9)=0.67, P=.04). More than 8 participants responded that they would like to monitor the wheelchair's condition using the new technology and purchase it at an average (SD) price of US $28.95 (18.13).

Conclusions

In this study, the association between wheelchair usage and failures showed that data-driven wheelchair inspection schedules should be determined through a collaborative approach involving researchers and stakeholders in wheelchair repair provision and older adult users. Older adults are interested in using new technology to engage in wheelchair servicing.

Ultralight wheelchair part failures are associated with sensor-monitored road shocks: A pilot study

Wheelchair part failures and repairs have significantly increased over the last decade, leading to severe consequences for wheelchair users. Servicing these devices by wheelchair repair technicians has reduced part failures. However, no tools or technologies have been developed to support servicing in practice. To inform servicing events, risk factors affecting wheelchair quality and reliability need to be identified. This pilot study tracks wheelchair usage for a week in the community for eight ultralight manual wheelchair users and assesses the relationship between usage variables and user-reported part failures over 20 months. The participants' preferences for using smart technology for wheelchair servicing were evaluated. At least 73 wheelchair part failures and two adverse consequences were reported. Data analysis indicated associations between part failure frequency, usage variable of road shocks, wheelchair maintenance frequency, and the user's demographic characteristics of training status and transportation. Six participants favored using smart technology for wheelchair servicing. This study's findings encourage the development of usage monitoring technology and failure prediction models to support technician-led servicing and prevent wheelchair failures and user consequences.

Estimating power wheelchair electronics lifespan based on real-world data

INTRODUCTION

Electronics are crucial to the operation and utility of power wheelchairs (PWCs). Existing research falls short in understanding electronics lifespan, which should inform proper maintenance and funding.

PURPOSE

This study investigates the lifespan of PWC electronics, aiming to estimate time until repair or replacement and identify contributing factors to variability in lifespan.

METHODS

Retrospective data from 1268 group 2 PWCs, collected from the Wheelchair Repair Registry, were analysed using Kaplan-Meier's survival analysis and Cox proportional hazards models.

RESULTS

Results indicate that 29.2% of PWCs experienced electronics-related repairs, with a median survival of 32.2 months. Significant predictors of reduced electronics survival included device type (group 3 hazard ratio (HR), 1.58; p = .003), distribution year in 2017 (HR, 1.82; p < .001) and distribution year in 2018 (HR, 4.08; p < .001). Manufacturer D was a marginally significant factor in reduced survival (HR, 1.66, p = .070).

CONCLUSION

These findings underscore the importance of proper maintenance and design in enhancing PWC reliability and user quality of life. Future research should expand data inclusivity and consider broader implications for global PWC users.

Power wheelchair usage and repair are associated: a retrospective analysis

Purpose: This study evaluates the effect of power wheelchair telemonitoring and battery charging training on user charging behavior and repair measures and assesses the relationship between wheelchair usage and repair measures to support technician-led servicing.Methods: This is a retrospective analysis of two matched cohorts with a total of n=237 users from the NHS service dataset. In the training cohort, a wheelchair usage telemonitoring device monitored the battery usage of n=119 power wheelchair users for 12 months. Users whose battery charging behavior was not optimal were instructed on appropriate charging practices. Wheelchair usage parameters of wheelchair drive and power time every month were used to predict repairs and associated costs.Results: Fifty-four out of 119 users in the training cohort did not charge batteries regularly and were instructed on appropriate charging. Twenty-six of them changed their behavior and charged their batteries every night. This cohort experienced reduced battery repairs by 18%, wheelchair repairs by 11%, and repair costs by £3,092 compared to a matched standard care cohort (n=118). User age and drive time were associated with repair measures. Drive time predicted time-to-failure for wheelchair parts and classified failure risk with the area under the receiver operating characteristic curve as 0.71 (95% CI 0.61 to 0.82; p<.001). Conclusions: By leveraging the significant relationships between wheelchair usage and repairs, wheelchair users at risk of part failures can be identified, and technician-led servicing tools for proactive interventions can be developed. Wheelchair battery health telemonitoring and instructing users on appropriate battery charging reduced repairs and associated costs.

Community-based wheelchair caster failures call for improvements in quality and increased frequency of preventative maintenance

STUDY DESIGN

Secondary data analysis of wheelchair failures and service repair logs from a network of wheelchair suppliers.

OBJECTIVE

To determine the frequency of wheelchair caster failures and service repairs across wheelchair manufacturers and models and investigate the relationships between them.

SETTING

Wheelchair caster failures and service repairs occurred in the community.

METHODS

Reported caster failure types were classified based on the risk they pose for user injuries and wheelchair damage. Caster failures experienced by users of tilt-in-space and ultralightweight manual wheelchair models and Group 2, 3 and 4 power wheelchair models between January 2017 and October 2019 were analyzed using Chi-Square tests for independence. Correlational analysis of failures and service repairs was performed.

RESULTS

A total of 6470 failures and 151 service repairs reported across four manufacturers and five models were analyzed. Failure types were significantly associated with manufacturers and models, respectively. Users of tilt-in-space wheelchairs, who require greater seating support, experienced twice the proportion of high-risk caster failures than the ultralightweight manual wheelchair users. Similarly, Group 3 and 4 power wheelchair users, who have complex rehabilitation needs, experienced 15-36% more high-risk failures than Group 2 users. Service repairs negatively correlated with high-risk manual wheelchair caster failures.

CONCLUSIONS

Wheelchair users who have greater seating and complex rehabilitation needs are at a higher risk for sustaining injuries and secondary health complications due to frequent caster failures. The study findings call for significant reforms in product quality and preventative maintenance practices that can reduce wheelchair failures and user consequences.

Accelerated wear testing shows that thermoplastic bushings could be a cost-effective and durable alternative to traditional bearings for wheelchair caster use

Introduction

Wheelchair caster bearings often suffer high-risk failures that lead to adverse consequences such as user injuries, suggesting that design improvements are necessary. This study aimed to compare thermoplastic bushings to standard roller bearings for potential improvements in durability and cost-effectiveness.

Methods

The durability and cost-effectiveness of two thermoplastic bushing models and two metallic ball-bearing models were tested using a standard lab-based accelerated wear testing protocol. Bushings and bearings were installed on a standard 8″ caster, and four samples per model underwent testing (16 total samples).

Results

All failures were experienced by the stem rolling element. The thermoplastic bushings experienced higher mean durability than the standard ball-bearings. There were significant differences in durability across the tested models, F(3,12) = 3.88, p = 0.04. The durability of thermoplastic bushing #2 was higher than the standard type ZZ shielded deep groove ball bearings, p < 0.05. There were significant differences in cost-effectiveness across the tested models, F(3,12) = 7.64, p = 0.004. The cost-effectiveness of both thermoplastic bushings were significantly higher compared to type 2RS sealed deep groove bearings, p < 0.05.

Conclusions

The use of thermoplastic bushings can lower product cost and potentially reduce caster failures in the community that are associated with adverse consequences including user injuries.

Rolling resistance of casters increases significantly after two years of simulated use

Introduction

Manual wheelchair propulsion is associated with upper limb pain and injury, and clinical guidelines recommend minimizing propulsive force to lower health risks. One of the strategies to reduce propulsive force is by minimizing rolling resistance (RR). Product testing studies suggest that RR of casters is affected by wear and tear which could have implications on the health risk of wheelchair users. The study will investigate the relationship between caster RR and environmental exposure using standard testing protocols.

Methods

RR of ten casters representing a range of diameters for different models of wheelchairs were measured before and after environmental exposure that includes corrosion, shock and abrasion simulating two years of community use.

Results

Four casters exhibited failures during durability testing, one catastrophically. Increases to RR after corrosion, shock and abrasion exposure were statistically significant using mixed-effects modeling, and four casters had increased RR greater than 20%.

Conclusions

Many of the casters evaluated exhibited increased RR forces and failure after environmental exposure. Improved caster design and use of corrosion resistant materials may reduce these failures. In addition, modification of the provision process could include replacement casters to reduce failures and avoid breakdowns that leave manual wheelchair users stranded or injured.