Application of 3D printing fracture models in treatment of intertrochanteric fracture

Abstract

Objective To report the application of 3D printing fracture models to assist the treatment of femoral intertrochanteric fracture using proximal femoral nail anti-rotation(PFNA)fixation. Methods From August 2014 to February 2015, 27 unstable intertrochanteric fractures were treated using PFNA. Of them, 12 used a 3D printing fracture model to assist the surgery and 15 did not. CT scanning was performed for the patients in 3D printing model group. Their anatomical data of . Dicom form were reconstructed into the . STL form data through M3D software. The 3D printing model was constructed using fused deposition modeling(FDM)technique. The length and diameter of the main screw and blade were measured based on the 3D printing prototyping before surgical planning. The 2 groups were compared in terms of operation time, intraoperative blood loss, postoperative drainage volume, hospital stay and Harris hip score at the final follow-up. Results No significant differences were found in the 3D printing model between surgical planning and actual operation in the respects of diameter of main PFNA screw(9. 42 ±0. 64 mm versus 9. 58 ±0. 16 mm), length of main PFNA screw(177. 50 ± 12. 90 mm versus 178. 33 ±20. 34 mm), or length of blade(84. 58 ±5. 94 mm versus 85. 42 ± 5. 57 mm)( P> 0. 05). The 27 patients obtained an average follow-up of 12. 4 months(from 10 to 16 months). The operation time(47. 8 ±5. 1 min), intraoperative blood loss(101.6±3.9 mL)and postoperative drainage volume(47. 3 ±5.9 mL)in the 3D printing model group were significantly less than those in the conventional group(61. 1 ±7. 5 min, 122. 3 ±9. 8 mL and 58. 6 ±6. 3 mL, respectively)(P 0. 05). Both groups obtained fine fracture union. No varus deformation of the hip joint or failure of implants was observed during the follow-up period. Conclusion 3D printing technique can manufacture an accurate model of intertrochanteric fracture, which may play an important role in improving efficiency and accuracy of reduction and PFNA fixation. Key words: Hip fractures; Fracture fixation, intramedullary; Bone nails; 3D printing