The Spring 2011 issue of Pediatric Physical Therapy published an interesting study on the use of supramalleolar orthoses and how they affect upper extremity use. Seventeen children with Down Syndrome were divided into two groups of treadmill training - one group of children wore supramalleolar orthoses and the other group did not. Both groups of children were followed every other month to video tape the use of the upper extremities during table top play. The children were followed from when they could pull to stand until independent walking. The results indicated that wearing supramalleolar orthoses did not affect hand support while standing.
Reference: Looper, Julia PT, PhD; Ulrich, Dale PhD Does Orthotic Use Affect Upper Extremity Support During Upright Play in Infants With Down Syndrome? Pediatric Physical Therapy: Spring 2011 - Volume 23 - Issue 1 - p 70–77 doi: 10.1097/PEP.0b013e318208cdea