Locking compression pediatric hip plate placement assisted by individualized navigation templates for pediatric hip diseases

Abstract

Objective To explore the feasibility and accuracy of a navigation template for placing screws in locking compression pediatric hip plate (LCP-PHP) based on digital design and three-dimensional (3D) printing technology. Methods From January 2012 to December 2014, the preoperative images of computed tomography (CT) were collected for 8 children of femoral neck fracture (n=4) and development dysplasia of hip (n=4). Individual proximal femur model was established by 3D printer. Reduction of fracture and cannulated screw of femoral neck or placement of LCP-PHP were simulated by computer. The screw through femoral neck was designed by software and printed to match proximal femur After reduction, it was placed into navigation template. After the preoperative feasibility of 3D modeling was confirmed, guide pins and screws were inserted with the intraoperative assistance of navigation template. Results During operation, navigation template with individualized design matched the bony markers of proximal femur. And 2-3 screws were accurately inserted into femoral neck for stabilizing the end of fracture. The results were basically the same between postoperative radiography and preoperative design. The implantation of screw took an average of 27.50 min. Radiology was used intraoperatively for an average of 6.0 times and wounds healed within one stage. Postoperative radiography showed excellent outcomes. Osteotomy of proximal femur was appropriate and posterior hip joint improved. Entry point, orientation and screw length were all consistent with virtual schemes and there was no screw wear-out. During a follow-up period of 6-12 months, femoral neck fracture and proximal femur osteotomy healed and the functions of hip joint were excellent (n=4) and fair (n=4) according to the Ratliff criteria. Conclusions Accurate placement of individualized navigation template of LCP-PHP may be achieved by 3D printing. This technology reduces iatrogenic damage of femoral neck epiphysis and blood supply, saves operative duration, minimizes intra-operative hemorrhage and decreases intraoperative patient-operator radiation exposure. It is worthy of wider popularization. Key words: Fracture of femoral neck; Dislocation of hip joint; Three-dimensional printing technology