Dynamic AFOs facilitate compliance, outcomes in children with cerebral palsy

Brace wear time, not torque, is key.

Dynamic orthoses offer an effective alternative to static devices for management of tip-toe gait and knee flexion contracture in children with cerebral palsy (CP), particularly because the dynamic devices are associated with greater compliance, according to separate studies from Sweden and France.

Cascade DAFO photo

By Jordana Bieze Foster, Lower Extremity Review March 2013

In 10 children with CP, researchers from the Medical University of Vienna found that wearing a dynamic ankle foot orthosis (AFO) 23 hours a day was associated with significant correction of tip-toe walking after three months. The AFO, which features a ring-shaped foot support, was designed to address intra-articular rotational misalignment at the ankle, according to Christian Grasl, Dipl Ing, a researcher in the Center for Medical Physics and Biomedical Engineering at the Medical University of Vienna, who presented his group’s findings at the ISPO World Congress in Hyderabad.

Just one of the 10 children continued to walk with a primary forefoot strike after the three months of AFO wear. Mean ankle dorsiflexion and foot progression angle for the group improved, with no loss of ankle power.

Similar effects could probably be achieved with a less aggressive regimen, Grasl said, but the Vienna researchers actually believe the 23-hour number makes intuitive sense to children and parents.

“It may be that 17 or 18 hours is enough, but it’s just easier to say 23 hours, which leaves about one hour for bathing and cleaning the device,” he said.

In a second study from the Regional Institute for Physical Medicine and Rehabilitation in Nancy, France, researchers found that dynamic knee ankle foot orthoses (KAFOs) designed to provide a low-load prolonged stretch were more effective than static KAFOs for managing knee flexion contracture in children with CP.

Thirty children with knee flexion contracture of at least 10° were randomized to receive dynamic or static KAFOs. After eight months of night use, knee flexion contracture had been reduced by a mean of 12.5° with the dynamic KAFO compared to just 3.5° with the static KAFO. Device tolerance was good or very good in 72.5% of patients in the dynamic group but just 31.8% of the static group.

“The key for success is the wearing time of the brace, not the level of torque. The practitioner must explain this to the family,” said Isabelle Heymann, a researcher at the Regional Institute for Physical Medicine and Rehabilitation, who presented her group’s findings in Hyderabad.

A third study from the University of Gothenburg in Sweden found that gait abnormalities related to leg length discrepancies (LLD) in children with CP can be addressed by adding an extra sole to the shoe of the shorter limb.

In eight children with a mean LLD of 1.73 cm, researchers added a split sole of 55-shore ethylene vinyl acetate (EVA) to the shoe of the shorter limb and compared spatiotemporal gait variables for that condition with two others, barefoot and unadjusted shoes only.

The extra-sole condition was the only one of the three in which percent of time in stance phase did not differ significantly between limbs, according to Roland Zugner RPT MSc, a doctoral student in the department of orthopedics at the University of Gothenburg, who presented the results in Hyderabad.

Source Lower Extremity Review

References

Outcome of 23H bracing for tip-toe walking children with cerebral palsy, Grasl C, Kranzl A, Csepan R. Presented at International Society of Prosthetics and Orthotics 2013 World Congress, Hyderabad, India, February 2013.

Superior efficacy of low-load prolonged stretch dynamic orthosis in cerebral palsy, Heymann I. Presented at International Society of Prosthetics and Orthotics 2013 World Congress, Hyderabad, India, February 2013.

Gait pattern in children with CP and leg length discrepancy, effects of an extra sole, Zugner R, Stefansdottir I, Nystrom-Eek M. Presented at International Society of Prosthetics and Orthotics 2013 World Congress, Hyderabad, India, February 2013.