Inclination, hip abduction, orientation, and tone affect weight-bearing in standing devices

Abstract

PURPOSE: With children who are unable to stand or walk independently in the community, therapists commonly use standing devices to assist lower-extremity weight-bearing which is important for bone and muscle health. In addition, positioning in hip abduction may improve hip stability and range of motion. This is the first study to explore the effect of angle of inclination, hip abduction, body orientation, and tone on weight-bearing in pediatric standing devices. METHODS: This descriptive exploratory study used a convenience sample of 15 participants (2 with normal tone, 5 with generalized hypotonia, and 8 with hypertonia) (mean age of 5 years and 10 months, range of 3 years 4 months to 9 years 7 months); 13 of whom used standing devices at home, as well as 2 typically developing siblings (normal tone). Each child stood in 36 positions to measure the amount of weight-bearing through footplates. RESULTS: Weight-bearing was highest with 60 degrees of abduction and no inclination (upright) in supine positioning for children with low and normal tone. Children with high muscle tone bore most weight through their feet with no abduction (feet together) and no inclination (upright) in prone positioning. Overall, supine positioning resulted in more weight-bearing in all positions for children with low and normal tone. Prone positioning resulted in slightly more weight-bearing in all positions for children with high tone. CONCLUSIONS: Weight-bearing was affected by all three of the variables (inclination, abduction, and orientation) for participants with high, normal, and low tone. To determine optimal positioning, all standers should include a system to measure where and how much weight-bearing is occurring in the device.