Abstract: Objective  To establish automated bony structure modeling, osteotomy planning, and patient-specific instrument guides design for the precise osteotomy for congenital radioulnar synostosis (CRUS). Methods  The computed tomography (CT) scan of bilateral forearms was performed on 17 patients with unilateral affected forearm. Bony structure modeling was performed using feature point recognition algorithms, and computer-aided design. The patient-specific osteotomy and osteosynthesis guides were designed based on the osteotomy plan, and the simulated surgery operation was performed on the resin model made using 3D printing and according to the digital model. Results  Patient specific instrument guides can be used to perform CRUS osteotomy surgery, and the results of the resin model surgery are consistent with the expected outcome. The interval between the osteotomy guide plate and the bone, the thickness of the osteotomy guide plate, the thickness of the osteosynthesis guide plate handle and the width of osteotomy groove are 3, 4, 9, 0.8 mm respectively. Such osteotomy/osteosynthesis guide plate can perform better and more accurately the corresponding operation. Conclusions  The patient specific instrument guides automatically generated by the assist of digital technology can help surgeon to complete the osteotomy of CRUS.

Key words: digital orthopedics, congenital deformity, osteotomy, patient-specific instrument guide