Corrective osteotomy using customized hydroxyapatite implants prepared by preoperative computer simulation

Abstract

Opening wedge corrective osteotomy usually requires a bone graft. However, it is difficult to shape the graft into an appropriate configuration. To resolve this problem, we developed an original computer program system that calculates the size and shape of a bone graft and cuts a hydroxyapatite block into the desired shape. Five patients with forearm deformity were included in this study. The amount of deformity and the three-dimensional (3D) shape of the bone graft to be inserted into the osteotomy site were calculated and designed by comparing bilateral 3D bone models. For the bone graft, a block of hydroxyapatite was cut based on the preoperative simulation. In addition, a customized osteotomy template was designed and manufactured before surgery, based on preoperative simulations and used during the actual operation. Corrective osteotomy based on simulations was achieved in all cases. The average angular deformities on anteroposterior and lateral radiographs were decreased from 16.8 degrees to 1.2 degrees and from 16.6 degrees to 0.6 degrees, respectively, after surgery. All patients had bone fusion within 5 months. Customized hydroxyapatite implants are helpful for accurate correction and good functional results.