The control group (n = 32) had a mean age of 10.5 years (min 5 years, max 16 years/18 males, 14 females). Primary GR was defined as a GR without having any kind of previous surgery regarding the lower extremity, selective dorsal rhizotomy and/or interventions like botulinum toxin injection, shock wave therapy or serial casting during the last 6 months (Fig. 1).