Abstract: Objective To evaluate the safety of 3D printed titanium alloy trabecular reconstruction rod, bone grafts and its clinical efficacy. Methods Sixty patients with osteonecrosis of femoral head (ONFH) stage Ⅱ (ACRO Ⅱ) were randomly divided into experimental group (titanium rod group) and control group (tantalum rod group). Patients were followed up at 6,12 and 24 months after the operation. Harris score and visual analogue scale (VAS) were used to evaluate the postoperative function. Changes of X-ray were observed before and after operation. The imaging evaluation was analyzed after 24 months.Results The Harris score was decreased in titanium rod group compared with that of tantalum rod group at six-month.There were no significant differences in Harris scores for other time points between two groups. Repeated measures analysis of variance showed that there was a significant difference in time effect. The X-ray staging results changed gradually before and after operation in two groups, stage Ⅲ and stage Ⅳ gradually increased with time. There was progress in ONFH after operation in two groups. No infection or rejection was found in the two groups. There were higher improvement rates of stage ⅡA and stage ⅡB. There were no significant differences in improvement rate and hip preservation rate between two groups.The transparent lines disappeared in the positive and lateral X-ray films 6 months after the operation. No new transparent lines were found. The bone enhancement was not found in two groups of patients during follow-up period. No stress occlusion and bone trabecular bone enhancement were observed in two groups. Conclusion Titanium rods are satisfactory for the treatment of femoral head necrosis in the early stage of ACRO Ⅱ, which is not recommended for the treatment of relatively large ACRO Ⅱ C stage of necrotic area.

Key words: femur head necrosis, hip fractures, metal trabeculae, titanium rods, tantalum rods, 3D printing