title: Reply to the letter by J. L. Heemskerk, et al.
authors.affiliation: Pediactric Orthopedic Department, Grenoble Alpes University Hospital, BP 217, 38043 Grenoble cedex 09, France. Electronic address: aurelien.courvoisier@gmail.com.
authors.forename: A
authors.initials: A
authors.lastname: Courvoisier