Grafts of autogenous coronoid process to reconstruct the mandibular condyle in children with unilateral ankylosis of the temporomandibular joint: long-term effects on mandibular growth

Injury to the mandibular condyle in children usually leads to malocclusion and disharmony of facial growth. Our aim was to study the facial growth after reconstruction of the mandibular condyle using autogenous coronoid process grafts in children with unilateral ankylosis of the temporomandibular joint (TMJ). We followed up 10 growing patients with unilateral bony ankylosis of the TMJ who had been admitted to the West China Hospital of Stomatology, Sichuan University (Chengdu, China) between 1 January 2008 and 31 December 2012. There were three boys and seven girls, age range 5–12 years at the time of operation. In each case, patients were treated by gap arthroplasty, reconstruction of the condyle with an ipsilateral coronoid process, and interposition of the pedicled temporalis fascial flap during one operation. The mean (range) postoperative follow up was 4.73 (3–6) years. Postoperative panoramic radiographs were taken, and the growth of the mandibular height and length on the affected side was measured and compared with the healthy side. All patients had an uneventful, normal recovery. The mean (range) maximal mouth opening at the end of follow up was 35.6 (32–41) mm. Both the height of the ramus and the length of the mandible continued to grow after successful treatment of the ankylosis (using autogenous coronoid process grafts for reconstruction of the condyle) but the deficit in growth was not completely made up. The final height of the ramus on the affected side (at the end of follow up) had increased by 25% (p=0.012) and the final length of the mandible on the affected side by 26% (p=0.010) compared with immediately after operation. For comparison of the rate of growth, the increased height of the ramus of the affected side was 47% lower (p=0.003), while the increased length of the mandible on the affected side was 27% shorter (p=0.008) compared with the healthy side. The mandible on the affected side continued to grow after successful treatment of the ankylosis, but the growth deficit was not made up completely. The rate of growth of the affected mandible seemed to be less than on the undisturbed side even after treatment of the ankylosis.