ObjectiveTo investigate the biomechanical properties of artificial ligament in the treatment of injuries to distal tibiofibular syndesmosis so as to provide a scientific basis for clinical application. MethodsSixteen fresh ankle specimens were harvested from 8 normal fresh-frozen cadavers. The initial tests were performed on 16 intact specimens (group A) and then the distal tibiofibular syndesmosis injury models were made (group B); the distal tibiofibular syndesmosis was fixed with artificial ligament in 8 specimens (group C) and with cannulated lag screw in the other 8 specimens (group D). The pros and cons of different fixation methods were analyzed by displacement, stress shielding effect, the strength and stiffness of ankle joints, the contact area of tibiotalar articular surface and the contact stress. ResultsUnder the physiological loading or combined with external rotation moment, the displacement of group C was significantly lower than that of groups B and D (P < 0.05), but no significant difference was found between groups A and C (P > 0.05); and there were significant differences among groups A, B, and D (P < 0.05). The rates of stress shielding in the tibia and fibula of group C were significantly lower than those of group D (t=-71.288, P=0.000;t=-97.283, P=0.000). The stress strength in tibia of group C was significantly higher than that of groups A and D (P < 0.05), but no significant difference was found between groups A and D (P > 0.05). Group C had the highest stress strength in fibula, followed by group A, group D had the lowest; differences were significant among 3 groups (P < 0.05). There was no significant difference in shear strength among groups A, C, and D (P > 0.05). The axial stiffness in tibia of group D was significantly lower than that of groups A and C (P < 0.05), but no significant difference was found between groups A and C (P > 0.05). The axial stiffness in fibula of group C was significantly higher than that of groups A and D (P < 0.05), but no significant difference was found between groups A and D (P > 0.05). Group C had the highest shear stiffness in tibia and fibula, followed by group D, group A had the lowest; differences were significant among 3 groups (P < 0.05). In groups A, C, and D, the contact area of tibiotalar articular surface gradually reduced, and the contact stress gradually increased, and differences were significant among 3 groups (P < 0.05). ConclusionFixation of distal tibiofibular syndesmosis injury with artificial ligament can better meet the physiological functions of the distal tibiofibular syndesmosis and has lower stress shielding, better stress distribution. Hopefully, it can reduce the complications of the distal tibiofibular syndesmosis injuries and become a better treatment choice.
ObjectiveTo explore the pathological role of high mobility group box chromosomal protein 1 (HMGB1) in osteoarthritis (OA) by comparing the difference of HMGB1 in the synoviocytes between OA and normal knees. MethodsSynoviocyte lines from OA and normal knees were collected and cultured. Immunohistochemistry and Western blot were applied to identify the difference of HMGB1 between the OA and normal synoviocyte lines. The eukaryotic expression vector containing human Pgenesil-1/HMGB1 small interfering RNA (siRNA) were constructed and identified. The synoviocyte lines were transfected with the eukaryotic expression vector of Pgenesil-1/HMGB1 siRNA (Pgenesil-1/HMGB1 siRNA group) and with Pgenesil-1 plasmid (Pgenesil-1 group) and were not transfected as a control (untransfected group). Western blot was applied to identify the difference of HMGB1 among groups, and the levels of interleukin 1β (IL-1β) and tumor necrosis factor α (TNF-α) protein synthesis in the supernatants were measured by ELISA. ResultsPrimary knee synoviocytes cultured in vitro were fibroblast-like cells with longspindle shape. The immunohistochemistry and immunofluorescence results showed positive staining for HMGB1 in cytoplasm and weak positive staining in the nucleus in the OA synoviocyte line, but positive staining for HMGB1 in the nucleus and weak positive staining in the cytoplasm in the synoviocyte line of normal knee. The level of HMGB1 in the OA synoviocytes (0.687±0.025) was significantly higher than that of normal synoviocytes (0.172±0.030) (t=32.159, P=0.000) by Western blot. The recombinant plasmid Pgenesil-1/HMGB1 siRNA was successfully constructed. The expression of HMGB1 protein in Pgenesil-1/HMGB1 siRNA group (0.134±0.048) was significantly lower than that of Pgenesil-1 group (0.581±0.032) and untransfected group (0.514±0.069) (P<0.05). ELISA results showed that IL-1β and TNF-α in supernatants of Pgenesil-1/HMGB1 siRNA group were significantly lower than those of Pgenesil-1 group and untransfected group (P<0.05). ConclusionThe up-regulated expression and expressed location (from nucleus to cytoplasm) of HMGB1 in the synoviocyte are closely related to OA. The siRNA targeting inhibition of HMGB1 gene expression can obviously inhibit IL-1β and TNF-α in supernatants of the OA synoviocyte line and delayed the inflammation of OA.
ObjectiveTo investigate the clinical outcome of Ponte osteotomy for old osteoporotic multi-segment vertebral fracture combined with thoracolumbar kyphosis in elderly. MethodsBetween April 2007 and December 2012, 11 elderly patients with thoracolumbar kyphosis caused by old osteoporotic multi-segment vertebral fracture received Ponte osteotomy. There were 4 males and 7 females, with an average age of 69 years (range, 62-76 years) and with an average disease duration of 4 years (range, 10 months to 7 years). A total of 51 vertebrae was involved in fracture, including T5 in 1, T8 in 1, T9 in 1, T10 in 5, T11 in 8, T12 in 11, L1 in 11, L2 in 10, and L3 in 3. Based on Frankel classification, there were 9 cases of grade E and 2 cases of grade D. The Cobb angle of thoracolumbar kyphosis and the distance of sagital plane between C7 plump line and the posterior superior corner of S1 (sagittal vertical axis distance, SVA) were measured at pre-operation, at 2 weeks after operation, and last follow-up. The effectiveness of the treatment was appraised by visual analogue scale (VAS). ResultsAll the operations were successfully completed. Cerebrospinal fluid leakage occurred in 3 cases, and was cured after symptomatic treatment. Eleven patients were followed up 22 months on average (range, 7-38 months). Back pain symptoms, the appearance, and the trunk balance were significantly improved after operation. Postoperatively neurological symptoms were not aggravated. In 2 cases of grade D, 1 case recovered to grade E, and 1 case had no improvement. Osseous fusion was observed at 6.7 months on average (range, 5-9 months) in 10 patients except 1 patient who had no complete fusion at 7 months after operation. There was no infection, failure of internal fixation, or other complications. At 2 weeks after operation and last follow-up, the VAS score, Cobb angle, and SVA were significantly improved when compared with preoperative ones (P<0.05), but no significant difference was found between at 2 weeks and last follow-up (P>0.05). The correction rate of Cobb angle was 70.6%±2.2% at 2 weeks after operation and was 66.7%±1.3% at last follow-up, showing no significant difference (t=25.20, P=0.13). ConclusionPonte osteotomy is effective for old osteoporotic multi-segment vertebral fracture combined with thoracolumbar kyphosis in elderly. It can obtain satisfactory sagittal balance.