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BACKGROUND: With the development of nanotechnology, silk fibroin/nano-hydroxyapatite composite materials used for tissue repair have been reported; however, there are few reports on its use in spinal stability.OBJECTIVE: To explore the feasibility of silk fibroin/nano-hydroxyapatite composite materials for the initial segmental stability of the reconstructed spine.METHODS: Thirty-six New Zealand rabbits were randomly divided into three groups, and the L4/5 nucleus pulposus was removed in all the animals. Autologous bone group was implanted with autologous bone, experimental group implanted intervertebrally with silk fibroin/nano-hydroxyapatite composite material, and control group implanted with hydroxyapatite.At 12 weeks after implantation, lumbar interbody fusion was observed using X-ray, the spinal stability of the fusion segments was measured by biomechanical test, and histologically, bone graft fusion and material degradation at the surgical site were observed.RESULTS AND CONCLUSION: (1) X-ray observation: In the autologous bone group, the experimental group and the control group, there were respectively 11, 7, 2 rabbits meeting the standard of fusion. (2) Biomechanical test: The spinal activity during flexion-extension was significantly lower in the experimental group than the autogenous bone group and control group (P < 0.05). (3) Histological observation: Bony union was found at the junction between the iliac bone and surrounding tissues in the autologous bone group, and a large number of bone cells and fibroblasts were found around the new bone, while woven bone was found inside. The material was partially degraded in the experimental group,fibrous tissues were visible in the surrounding tissue, new woven bone was found inside, and pit cells and bone cells were scattered. Blood vessel growth around the material was visible in the control group, and a large number of macrophages were found inside the material. To conclude, the silk fibroin/nano-hydroxyapatite composite material has good biocompatibility and mechanical properties, which could rebuild the initial segmental stability in the rabbit spine in the short time.
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Objective To observe the clinical efficacy of loop plate elastic fixation for treatment of distal radioulnar joint dislocation.Methods From December 2014 to November 2016,11 patients with distal radioulnar joint dislocation were treated by loop plate elastic fixation.They were 7 males and 5 females,aged from 23 to 56 years (average,37.5 years).The dislocations were volar in 2 cases,dorsal in 7,transversal in 2 and longitudinal in one.Of them,6 were complicated with ulnar fracture,2 with radial fracture and one with radioulnar fracture.All the fractures were closed.Functional outcomes of the wrist were assessed by the Gartland-Werley scoring system,range of motion and grip strength at the last follow-up.Results The 12 patients were followed up from 6 to 18 months (average,12 months).Reduction of the distal radioulnar joint dislocation was confirmed in all by the anteroposterior and lateral X-ray films after operation.All the concomitant fractures were healed after 2 to 5 months (average,3 months).No re-dislocation of the distal radioulnar joint occurred.According to the Garland-Werley scoring at the last follow-up,the functional outcomes of the wrist were excellent in 10 patients,good in one and fair in one.There were no significant differences between the healthy and affected wrists in active range of flextion or extension,radial or unlnar deviation,pronation or supination,or grip strength (P ＞ 0.05).No infection,skin necrosis,internal fixation failure,dislocation recurrence or traumatic arthritis was observed during follow-up.The loop plate had to be removed in one case because of soft-tissue irritation.Conclusion Loop plate elastic fixation for distal radioulnar joint dislocation may provide firm fixation as well as preserve physiological micro-motion of the joint,leading to fine functional recovery of the wrist and satisfactory short-term outcomes.