The application of 3D printed customized porous tantalum acetabular patch for adult DDH hip reconstruction

Objective To explore the feasibility, safety and efficacy of customized porous tantalum acetabular patch made by three-dimensional (3D) printing technique in treating adult developmental dysplasia of the hip (DDH). Methods Eight adult patients with CroweⅠtype DDH (2 men and 6 women, with a mean age of 43.75±7.81 years, range 33-58 years) who were treated with 3D printed customized porous tantalum acetabular patch hip reconstruction from January 2017 to September 2017 were included. The 3D printing technique was used for reconstructing and designing the optimal acetabular patch for the personalized hip joint of each patient. The acetabular patch was subjected to porous processing and finite element analysis until the biomechanical requirements were met. The 3D printing of porous tantalum acetabular patch and post-processing was subsequently performed. The acetabular patch was implanted through the anterior approach of the hip joint. The operative duration, intraoperative blood loss and complications were recorded. All the included patients were followed up at 1.5, 3 and 6 months postoperatively. Pain was assessed using the visual analog scale (VAS), and the hip joint function was evaluated using the Harris score and gait analysis. The patients underwent anterior-posterior radiography and 3D computed tomography of the hip joint aiming to observe the position of the acetabular patch and osteoarthritis progression. Results The mean operative duration was 1.13±0.23 h, and the mean blood loss was 114.17±41.22 ml. All patients were followed up for 6 to 12 months, with an average of 8.2 months. The mean lateral central-edge angle and anterior central-edge angle ranged from 9.83°±5.34° preoperatively to 32.67°±2.53° postoperatively and from 3.83°±2.79° preoperatively to 21.67°±1.87° postoperatively, respectively. The rate of acetabular coverage increased from 57.33%±7.97% preoperatively to 87.33%±4.56% postoperatively. The VAS and Harris scores ranged from 2.92±0.79 preoperatively to 0.83±0.72 postoperatively and from 69.67±4.62 preoperatively to 84.25±4.14 postoperatively with statistically significant difference, respectively. The results of gait analysis showed that the step speed, stride, the range of motion of hip and knee were better than that preoperatively. The images suggested a close contact between the tantalum acetabular patch and the iliac bone without loosening and progress of osteoarthritis in hip joint. Conclusion 3D printed customized porous tantalum acetabular patch could reconstruct the defect of acetabular, increase the coverage, and delay the progress of osteoarthritis of the hip joint. This method could reduce the difficulty of hip reconstruction, and the patients could obtain better joint function at the early stage. Key words: Bone diseases, development; Imaging, three-dimensional; Tantalum; Porosity