Clinical Bottom Line
Maureen Donohoe, PT, DPT, PCS
Alfred I. duPont Hospital for Children, Wilmington, Delaware
Holly Cintas, PT, PhD, PCS
National Institutes of Health, Bethesda, Maryland
“How could I apply this information?”
In a review of the data, ankle strength is associated with skills that have an important effect on activities of daily living such as standing on 1 foot and walking on stairs without a handrail. Riding a bicycle without training wheels is also associated with ankle plantar flexion strength in this study, but only 50% of the children tested found riding a bicycle easy whereas 35% could not perform the task. This task may be self-limiting because of risk of fracture, but it is also considered more recreational than functional, so it may not be a priority for these individuals. When planning for a person who has type I osteogenesis imperfecta (OI), it is important to identify potential strength deficits as well as functional limitations in order to train skills while strengthening.
“What should I be mindful about in applying this information?”
It is important to note that 45% of the OI group subjects had at least 1 fracture in the year before testing whereas none of the control group subjects had documented fractures. Immobilization and decreased activity due to fractures cause disuse atrophy. Although there is a high correlation between ankle strength and higher functional skills such as standing on 1 foot and managing stairs without a rail, these children are at risk for fractures, so adaptations may be necessary to safely perform these skills. Although strengthening may be beneficial, especially for children who have been immobilized and have secondary weakness, it alone will not create skill. It is a complement to gaining skill. For children with OI, strengthening may create a stronger extremity that is complicated by collagen defects impacting on joint stability and potential alignment issues due to long bone fractures.