[APPLICATION OF THREE-DIMENSIONAL PRINTING CUSTOMIZED BONE CEMENT MODELS ON REPAIR OF BONE DEFECT OF LIMBS]

To determine the feasibility of fabricating molds using a three-dimensional (3D) printer for producing customized bone cement for repairing bone defect.

Between February 2015 and March 2016, 13 patients with bone defects were treated. There were 9 males and 4 females with an average age of 38.4 years (range, 20-58 years), including 7 cases of chronic osteomyelitis, 3 cases of bone tuberculosis, 2 cases of bone tumor, and 1 case of ischemic necrosis. The defect located at the humerus in 3 cases, at the femur in 4 cases, and at the tibia in 6 cases. The defect ranged from 4.5 to 8.9 cm in length (mean, 6.7 cm). Before operation, Mimics10.01 software was used to design cement prosthesis, 3-matic software to design shaping module which was printed by 3D technology. After removal of the lesion bone during operation, bone cement was filled into the shaping module to prepare bone cement prosthesis for repairing defect.

The measurement result from Image J software showed that the match index of interface between the mirror restored digital and bone interface was 95.1%-97.4% (mean, 96.3%); the match index of interface between bone cement prosthesis and bone interface was 91.2%-94.7% (mean, 93.2%). It was one time success during separation between formed bone cement and shaping module without any shatter or fall off. All incisions healed by first intention. The cases were followed up 5-17 months (mean, 9.4 months). X-ray films and CT scans showed good position of bone cement prosthesis without any fracture; no peripheral fracture occurred.

3D printing customized bone cement shaping module can shorten the operation time, and customized bone cement prothesis has good match with bone interface, so it can avoid further adjustment and accord with the biomechanical rules of surgical site.