Tibial lenghtening through callus distraction in a patient with Schmid-type metaphyseal chondrodysplasia with a novel COL10A1-mutation

Abstract

We report on a patient with Schmid-type metaphyseal chondrodysplasia (MCDS) carrying a novel COL10A1 mutation who underwent bilateral tibial lengthening at the age of 16.5 years using the technique described by Ilizarov. The disease-causing mutation Phe554Leu (g. 1660 T>C) represents the most amino terminal mutation within the NC1-domain of collagen type X described in MCDS so far. Failure of consolidation of the anterior distraction callus required secondary conversion to intramedullary nailing 344 days after primary surgery. Length gained was 5 cm (17.2% of tibial length), and healing index was 160 days/cm (46.5 days/percentage). This is the first case of callus distraction reported in a patient carrying a defined collagen X missense mutation. The associated defect in endochondral ossification may represent a central factor leading to the failure of callus consolidation.