"Bedside" test of static rear stability of occupied wheelchairs

The assessment of static stability can be helpful in wheelchair prescription and adjustment, but ordinarily requires a tipping platform. We developed a simple "bedside" test of rear wheelchair stability, using a goniometer and a plumb line. The angle of the wheelchair handle while the occupied wheelchair was on a level surface was subtracted from the angle measured while the occupied chair was balanced over the rear axle. The intraobserver and interobserver reliability and the validity in comparison with platform testing were assessed by studying 30 patient-occupied wheelchairs. There was a high correlation (r = 0.93, p less than 0.001) between the values obtained from the beside and platform tests and no significant difference between them. Intraobserver and interobserver reliabilities were 0.87 (p less than 0.001) and 0.94 (p less than 0.001). There was no significant difference between the first and second test values done by a single observer; the mean difference (+/- 1SD) between observers, 1.3 degrees (+/- 1.6 degrees), was small but statistically significant. The bedside test is simple, reliable, valid, and suitable for use as a screening test for the platform assessment of rear stability.