[1] Univ British Columbia, Dept Orthopaed, Vancouver, BC, Canada
[2] Univ British Columbia, Dept Phys Therapy, Vancouver, BC, Canada
[3] BC Childrens Hosp, Dept Orthopaed Surg, Vancouver, BC, Canada
[4] BC Childrens Hosp, Dept Physiotherapy, Vancouver, BC, Canada
[5] Uppsala Univ, Dept Surg Sci, Sect Orthopaed, Uppsala, Sweden
[6] Nicklaus Childrens Hosp, Orthoped Sports Med & Spine Inst, Miami, FL USA
[7] Washington Univ, Sch Med, Dept Orthopaed Surg, St Louis, MO USA
[8] Scottish Rite Children, Dallas, TX USA
[9] Univ Texas Dallas, Southwestern Med Ctr, Dallas, TX USA