[Treatment of severe distal humeral bone defects with three-dimensional printing technology].

Objective:To explore the application of three-dimensional (3D) printing technology in precise and individualized surgical treatment of severe distal humeral bone defect. Methods:Five patients with severe distal humeral bone defects were treated with customized 3D printing prostheses between December 2010 and December 2015. There were 4 males and 1 female, with an age of 23-57 years (mean, 35 years); and the length of the bone defect was 5-12 cm (mean, 8 cm). The cause of injury was mechanical injury in 2 cases and strangulation in 3 cases. All of them were the open fracture of Gustilo type Ⅲ. There were 2 cases of radial fracture, 1 case of cubital nerve injury, and 3 cases of radial nerve injury. The time from injury to one-stage operation was 6-18 hours (mean, 10 hours). The operation time, intraoperative blood loss, and intraoperative fluoroscopy were recorded. During follow-up, the anteroposterior and lateral X-ray films of the elbow joints were performed to identify whether there was prosthesis loosening; Mayo Elbow Performance Score (MEPS) and upper extremity Enneking score were used to evaluate limb function. Results:The operation time was 140-190 minutes (mean, 165 minutes). The intraoperative blood loss was 310-490 mL (mean, 415 mL). The intraoperative fluoroscopy was 1-3 times (mean, 1.6 times). Five patients were followed up 14-38 months (mean, 21 months). The wound exudate occurred in 1 case and cured after anti-inflammatory local dressing change; the subcutaneous hematoma occurred in 1 case, and improved after color Doppler ultrasound guided puncture and drainage. The MEPS scores and the Enneking scores were all significantly improved when compared with preoperative ones ( P<0.05). Except MEPS score between 6 and 12 months after operation had no significant difference ( P>0.05), there were significant differences in MEPS scores and Enneking scores between the other time points ( P<0.05). During the follow-up, no prosthetic loosening or joint dislocation occurred. Conclusion:3D printing technology can achieve personalized treatment of severe distal humeral bone defects, obtain relatively good elbow joint function, and has less postoperative complications and satisfactory effectiveness.