Abstract: Objective:To use 3D printing titanium alloy pelvic prosthesis to reconstruct the pelvis in a patient with metastatic acetabulum tumor, and to explore a novel method in the treatment of acetabulum tumor. Methods: One patient with metastatic acetabulum tumor was selected.The pelvic CT scan was conducted in the patient.Three-dimensional reconstruction of pelvic CT was conducted using Mimics 14.0 Software. The 3D printing stereo lithography apparatus resin pelvic model with 1:1 scale was manufactured. The 3D printing osteotomy guide was designed and manufactured in accordance with the preoperative designed osteotomy scope; 3D printing titanium alloy pelvic prosthesis was designed on the basis of mirror image normal side hemi-pelvis and manufactured by electron beam melting 3D printing technology. After the osteotomy assisted with 3D printing osteotomy guide,pelvic prosthesis was implanted to the designed location. Results: Several follow-ups were reviewed in the patient within postoperative 12 months. The results of X-ray image showed there were no signs of pelvic prosthesis displacement and obvious migration.The SF-36 score(the MOS item shorted from health survey)was 75.35 points at 12 months after operation; MSTS was 11 points at 12 months after operation.The Harris score of affected side hip joint was 52 points at 12 months after operation.The motion function of lower limbs after operation of the patient was restored.The daily actions such as walking and standing could be done by herself with the assistance of crutch. Conclusion: In this study,3D printing pelvic prosthesis achieve the accurate reconstruction of pelvis and ameliorate the postoperative motion function of the patient.

Key words: acetabulum tumor, anatomical reconstruction, osteotomy guide, 3D printing