The findings of this study. Intervention with systemic etanercept monotherapy equivalent to the recommended human dose allows mandibular growth towards an original morphology by significantly improved growth of the total posterior mandibular height (see TPMH variable at small arrow). Systemic etanercept (0.8 mg/kg weekly) administration is superior to IA TMJ etanercept administration at times of inflammatory flares in maintaining mandibular vertical growth. All three groups demonstrated an unfavourable clockwise posterior mandibular rotation pattern, illustrated by an opening of Angle 3 (large arrow). The most pronounced posterior mandibular rotation was observed in the IA saline group in which a closing of Angle 2 also occurred.