The present paper is aimed to study the preparation and application of individual artificial bone of carbon/carbon composites. Using computer tomography images (CT), we acquired a three-dimensional image. Firstly, we described bone contour line outlined with manual and automatic method by the binary volume data. Secondly, we created 3D object surface information by marching cubes. Finally, we converted this information to non-uniform rational B-spine (NURBS) by using geomagic software. Individual artificial bone with carbon/carbon composite was prepared through the CNC Machining Center. We replaced the humeral head of the tested rabbit, and then observed the effects of implantation in neuroimaging and pathological section. Using this method, we found that the bone shape processed and bone shape replaced was consistent. After implantation, the implant and the surrounding bone tissue bound closely, and bone tissue grew well on the surface of the implant. It has laid a sound foundation of the preparation using this method for individual artificial bone of carbon/carbon composite material.
Animals ; Bone Substitutes ; chemistry ; Carbon ; chemistry ; Imaging, Three-Dimensional ; Rabbits ; Software ; Tomography, X-Ray Computed

Objective To compare the efficacy of direct anterior approach ( DAA ) and posterolateral approach (PA) in hip arthroplasty for elderly patients with femoral neck fractures. Methods A retrospective case-control study was conducted to analyze the clinical data of 67 elderly patients with femoral neck fractures admitted to Second People's Hospital of Changzhou City, Affiliated Hospital of Nanjing Medical University from July 2015 to December 2017. There were 25 males and 42 females, aged 60-90 years [(76. 1 ± 7. 6)years]. There were 31 patients with right femoral neck fracture and 36 with left femoral neck fracture, all of whom underwent operations within 72 hours after injury. There were 18 patients with type III and 49 with type IV according to Garden typing. All patients were treated with total hip arthroplasty. Direct anterior approach ( DAA) was performed in 36 patients ( DAA group) and posterior approach ( PA) was performed in 31 patients ( PA group) . The operation time, intraoperative blood loss, postoperative drainage, recessive blood loss, total blood loss, the time when the patients got out of bed, and hospitalization time were compared between the two groups. Visual analogue scale ( VAS) and Harris score were used to evaluate hip joint function one month after operation. The complications of the two groups were recorded. Results All patients were followed up for 3-6 weeks, with an average of one month. The operation time of DAA group was longer than that of PA group [(75. 0 ± 10. 5)minutes vs. (54.0±11.4)minutes] (P<0.01). The DAA group had less intraoperative blood loss [(174.3 ± 60.1)ml vs. (254.8±79.9)ml] (P<0.05), total blood loss [(745.7 ±238.8)ml vs. (977.9 ± 301. 9)ml] (P<0. 05), recessive blood loss [(315. 4 ± 196. 7)ml vs. (457. 7 ± 286. 2)ml] (P<0. 05) than the PA group. There was no significant difference in the postoperative drainage between DAA groupandPAgroup[(246.1 ±110.1)ml vs. (265.3±164.2)ml] (P >0.05). DAA group had shorter durations in terms of the time when patients got out of bed [(23. 7 ± 18. 1)hours vs. (35. 1 ± 22. 5)hours] (P<0. 01) and hospitalization time [(9. 2 ± 1. 5)days vs. (12. 3 ± 2. 0)days] than the PA group (P <0. 05). The VAS scores of the DAA group and PA group at 1 month after surgery [(3. 0 ± 1. 9)points vs. (3. 3 ± 1. 9) points] and the Harris score [(87. 9 ± 6. 5) points vs. (87. 0 ± 6. 1)points ] were not significantly different (P>0. 05). Intraoperative and postoperative complications included femoral periprosthetic fracture in three patients, lateral femoral nerve injury in two patients and severe anemia requiring blood transfusion in two patients in DAA group. In the PA group, there was one patient with deep venous thrombosis of the lower extremity at one month after operation, two patients with posterior dislocation of the hip, four patients with periprosthetic fracture and four patients with severe anemia requiring blood transfusion (P>0. 05). Conclusion For femoral neck fracture in the elderly, compared with PA hip arthroplasty, DAA hip arthroplasty has less bleeding, earlier time to get out of bed and shorter hospital stay, with satisfactory short-term results.