Outcomes
malocclusion, U1-SN, Pog’-G’, overjet, condyle
SECONDARY
The primary outcome was condylar height measured by MRI (1.5-Tesla imager, Signa; General Electric, Milwaukee, WI, USA). Sagittal images with closed- and open-mouth positions and coronal images of the condyle were acquired for evaluation of disc position, condylar bone status and height [
The condylar height measured by three-circle method in MRIThe secondary outcome was the degree of skeletal Class II malocclusion measured by lateral cephalometric films, including the following variables: ∠SNA, ∠SNB, ∠ANB, incisor overjet, Wits appraisal, Y-Axis angle, Pog’-G’ (Pog’, pogonion of soft tissue; G’, a plane perpendicular to Frankfort horizontal plane through glabella), Sn-G’ (Sn, subnasale), U1-SN and, U1-L1. Shanghai Ninth People’s Hospital standard cephalometric analysis was used under Dolphin 11.5 software (Dolphin Imaging, Chatsworth, CA, USA) for measurement before operation and at 12-month follow-up (Fig. 
Cephalometric measurement. To guarantee the accuracy, MRIs and cephalometric radiographs were blindly evaluated by 2 clinicians (J.S & H.Z) twice at a 2-week interval. The average value of the 2 clinicians was calculated for comparison. If a statistical difference by a paired 