Mandibular Distraction in a Patient With Type II Collagenopathy.

Kniest dysplasia is an extremely rare form of type II collagenopathy associated with cleft palate, micrognathia, shortened trunk, arms and legs, and club foot. The authors present a case of an infant with this disorder who also had micrognathia and respiratory distress for which mandibular distraction was performed. Although abnormal collagen and impaired endochondral ossification is noted with Kniest dysplasia, adequate bone formation was observed across the distraction gap. Nonetheless, despite stable mandibular advancement, failure to consider concomitant restrictive lung disease resulted in tracheostomy dependence. The authors demonstrate that while successful bone regeneration can be achieved through distraction of intramembranous facial bones, discretion must still be employed in patients with collagenopathies.