BACKGROUND:The asymmetrical biomechanical environment of adolescent idiopathic scoliosis can lead to further wedge deformation of the vertebral body,which may affect cardiopulmonary function and compress nerves in severe cases.Adolescent idiopathic scoliosis with different degrees of scoliosis should be treated with exercise,bracing,and surgery.However,the mechanical mechanism of selecting an orthopedic approach remains unclear due to the individual variability of patients.OBJECTIVE:To investigate the biomechanical mechanism of different orthopedic modalities for the treatment of adolescent idiopathic scoliosis to provide a basis for clinical selection of treatment modalities based on the spine model of adolescent idiopathic scoliosis patients.METHODS:Based on the CT images of an adolescent idiopathic scoliosis patient,a scoliosis model(C7-L5)was reconstructed in Mimics software in three dimensions,and lateral thrust force was applied at the T8/T9 thorax and vertical distraction force was applied over the C7 vertebra with the magnitude of 20,40,60,80,100,and 120 N.The intervertebral disc stress and vertebral displacement in concave and convex sides,and Cobb angle of the spine were analyzed under two orthopedic modalities.RESULTS AND CONCLUSION:(1)With lateral thrust,there was no significant change in the C7T1-T7T8 intervertebral disc.The concave and convex stress of T7T8-L4L5 segment decreased first and then increased with the increase of lateral thrust force.The correction effect of lateral thrust on the segment near T8T9 was obvious and weakened with the extension of the segment to the cephalic and caudal ends.At 120 N of lateral thrust,the thoracic Cobb angle changed from 53.2° to 32.5° and the lumbar Cobb angle changed from 50.2° to 43.9°.(2)With the vertical distraction,the thoracic intervertebral disc stresses first decreased and then increased,and all the lumbar disc stresses decreased.The C7 displacement was the most obvious,and the correction effect gradually diminished with the segment extended to the caudal end.At a vertical distraction force of 120 N,the thoracic Cobb angle changed from 53.2° to 39.4° and the lumbar Cobb angle changed from 50.2° to 47.6°.(3)It is concluded that both orthopedic modalities provide improvement in the degree of scoliosis,with the thoracic correction being greater than the lumbar correction.Also,the asymmetric stress distribution on the concave and convex sides is improved,which contributes to normal bone growth.A vertical distraction approach is appropriate for larger Cobb angles,and a lateral thrust approach is appropriate for smaller Cobb angles.The results of this study help to understand the mechanism of spinal orthosis and provide a theoretical basis for the choice of orthopedic approach.

BACKGROUND:The asymmetrical biomechanical environment of adolescent idiopathic scoliosis can lead to further wedge deformation of the vertebral body,which may affect cardiopulmonary function and compress nerves in severe cases.Adolescent idiopathic scoliosis with different degrees of scoliosis should be treated with exercise,bracing,and surgery.However,the mechanical mechanism of selecting an orthopedic approach remains unclear due to the individual variability of patients.OBJECTIVE:To investigate the biomechanical mechanism of different orthopedic modalities for the treatment of adolescent idiopathic scoliosis to provide a basis for clinical selection of treatment modalities based on the spine model of adolescent idiopathic scoliosis patients.METHODS:Based on the CT images of an adolescent idiopathic scoliosis patient,a scoliosis model(C7-L5)was reconstructed in Mimics software in three dimensions,and lateral thrust force was applied at the T8/T9 thorax and vertical distraction force was applied over the C7 vertebra with the magnitude of 20,40,60,80,100,and 120 N.The intervertebral disc stress and vertebral displacement in concave and convex sides,and Cobb angle of the spine were analyzed under two orthopedic modalities.RESULTS AND CONCLUSION:(1)With lateral thrust,there was no significant change in the C7T1-T7T8 intervertebral disc.The concave and convex stress of T7T8-L4L5 segment decreased first and then increased with the increase of lateral thrust force.The correction effect of lateral thrust on the segment near T8T9 was obvious and weakened with the extension of the segment to the cephalic and caudal ends.At 120 N of lateral thrust,the thoracic Cobb angle changed from 53.2° to 32.5° and the lumbar Cobb angle changed from 50.2° to 43.9°.(2)With the vertical distraction,the thoracic intervertebral disc stresses first decreased and then increased,and all the lumbar disc stresses decreased.The C7 displacement was the most obvious,and the correction effect gradually diminished with the segment extended to the caudal end.At a vertical distraction force of 120 N,the thoracic Cobb angle changed from 53.2° to 39.4° and the lumbar Cobb angle changed from 50.2° to 47.6°.(3)It is concluded that both orthopedic modalities provide improvement in the degree of scoliosis,with the thoracic correction being greater than the lumbar correction.Also,the asymmetric stress distribution on the concave and convex sides is improved,which contributes to normal bone growth.A vertical distraction approach is appropriate for larger Cobb angles,and a lateral thrust approach is appropriate for smaller Cobb angles.The results of this study help to understand the mechanism of spinal orthosis and provide a theoretical basis for the choice of orthopedic approach.

Objective:To compare the effectiveness of TightRope system and plate-screw internal fixation in the treatment of avulsion fractures of the posterior calcaneal tuberosity of Beavis type Ⅱ.Methods:A retrospective study was conducted to analyze the clinical data of the 42 patients with avulsion fracture of the posterior calcaneal tuberosity of Beavis type Ⅱ who had undergone surgical treatment at Foot-ankle Surgery Center, The Fourth Hospital of Wuhan from January 2019 to January 2024. There were 25 males and 17 females, with an age of (64.4±10.1) years. The left side was affected in 23 cases and the right side in 19 cases. The patients were divided into 2 groups according to their different ways of internal fixation: a TR group of 22 cases subjected to open reduction and internal fixation with TightRope system and a PS group of 20 cases subjected to open reduction and plate-screw internal fixation. The operation time, bone healing time, complications, and American Orthopaedic Foot & Ankle Society (AOFAS) ankle-hindfoot score, MOS item short form health survey (SF-36) score and visual analogue scale (VAS) at 12 months after operation were compared between the 2 groups.Results:There were no significant differences in the preoperative clinical baseline data between the 2 groups, indicating comparability ( P>0.05). All patients were followed up for (19.9±3.1) months. In the TR group, the operation time [(59.3±7.1) min] was significantly shorter than that in the PS Group [(72.1±10.7) min], the incidence of complications [4.5% (1/22)] significantly lower than that in the PS group [35.0% (7/20)], and the AOFAS ankle-hindfoot score [(83.5±8.2) points] and SF-36 scale score [(88.2±5.3) points] were significantly higher than those in the PS Group [(64.4±10.8) points and (78.6±11.2) points] (all P<0.05). There was no significant difference in the bone healing time or VAS pain score at 12 months after operation between the 2 groups ( P<0.05). Conclusions:In the treatment of avulsion fractures of the posterior calcaneal tuberosity of Beavis type Ⅱ, compared with the plate-screw internal fixation, the TightRope system can shorten operation time, improve functional recovery, and reduce complications.

Objective:To compare the effectiveness of TightRope system and plate-screw internal fixation in the treatment of avulsion fractures of the posterior calcaneal tuberosity of Beavis type Ⅱ.Methods:A retrospective study was conducted to analyze the clinical data of the 42 patients with avulsion fracture of the posterior calcaneal tuberosity of Beavis type Ⅱ who had undergone surgical treatment at Foot-ankle Surgery Center, The Fourth Hospital of Wuhan from January 2019 to January 2024. There were 25 males and 17 females, with an age of (64.4±10.1) years. The left side was affected in 23 cases and the right side in 19 cases. The patients were divided into 2 groups according to their different ways of internal fixation: a TR group of 22 cases subjected to open reduction and internal fixation with TightRope system and a PS group of 20 cases subjected to open reduction and plate-screw internal fixation. The operation time, bone healing time, complications, and American Orthopaedic Foot & Ankle Society (AOFAS) ankle-hindfoot score, MOS item short form health survey (SF-36) score and visual analogue scale (VAS) at 12 months after operation were compared between the 2 groups.Results:There were no significant differences in the preoperative clinical baseline data between the 2 groups, indicating comparability ( P>0.05). All patients were followed up for (19.9±3.1) months. In the TR group, the operation time [(59.3±7.1) min] was significantly shorter than that in the PS Group [(72.1±10.7) min], the incidence of complications [4.5% (1/22)] significantly lower than that in the PS group [35.0% (7/20)], and the AOFAS ankle-hindfoot score [(83.5±8.2) points] and SF-36 scale score [(88.2±5.3) points] were significantly higher than those in the PS Group [(64.4±10.8) points and (78.6±11.2) points] (all P<0.05). There was no significant difference in the bone healing time or VAS pain score at 12 months after operation between the 2 groups ( P<0.05). Conclusions:In the treatment of avulsion fractures of the posterior calcaneal tuberosity of Beavis type Ⅱ, compared with the plate-screw internal fixation, the TightRope system can shorten operation time, improve functional recovery, and reduce complications.

BACKGROUND:Ankylosing spondylitis is a chronic inflammatory disease with chronic rheumatic immunity.Soft tissue ossification and fusion and spinal stiffness can cause biomechanical changes. OBJECTIVE:To reconstruct the lumbar-sacral intervertebral disc in ankylosing spondylitis patients with lumbar kyphosis by finite element analysis,and to study the range of motion of each segment of T11-S1 and the biomechanical characteristics of annulus fibrosus and nucleus pulposus. METHODS:The imaging data were obtained from an ankylosing spondylitis patient with lumbar kyphosis.The original CT image data of continuously scanned spine were imported into Mimics 21.0 in DICOM format,and T11-S1 was reconstructed respectively.The established model was imported into 3-Matic software in the format of"Stl"to reconstruct the intervertebral disc,and the fibrous intervertebral disc model was obtained.The improved model was further imported into Hypermesh software,and the vertebra,nucleus pulposus,annulus fibrosus and ligament were mesh-divided.After the material properties were given,the model was imported into ABAQUS software to observe the range of motion of each vertebral body in seven different working conditions of T11-S1,and analyze the biomechanical characteristics of each segment of annulus fibrosus and nucleus pulposus. RESULTS AND CONCLUSION:(1)The range of motion of L1 vertebrae was higher than that of other vertebrae under six different working conditions:extension,forward flexion,rotation(left and right),and lateral flexion(left and right).The maximum range of motion was 2.18° during L1 vertebral flexion,and the minimum range of motion was 0.12° during L5 vertebral extension.(2)The annular fiber flexion at L2-L3 segments was greater than the extension(P<0.05),and the annular fiber flexion at L3-L4 and L4-L5 segments was less than the extension(P<0.05).The left rotation of L1-L2 annular fibers was greater than the right rotation(P<0.05).The left flexion of the annulus was greater than the right flexion in L1-L2,L2-L3,L3-L4,L4-L5 and L5-S1 segments(P<0.05).(3)The nucleus pulposus stresses of T11-L12,L1-L2,L2-L3,L3-L4 and L4-L5 segments in forward flexion were greater than in extension(P<0.05).The left rotation of T12-L1 and L3-L4 segments was smaller than the right rotation(P<0.05),and that of T11-T12,L1-L2,and L2-L3 segments was larger than the right rotation(P<0.05).The left flexion was larger than the right flexion in the T11-S1 segment.(4)It is concluded that in ankylosing spondylitis patients with lumbar kyphosis,the minimum range of motion of the vertebral body is located at the L5 vertebral body in extension.To prevent fractures,it is recommended to avoid exercise in the extension position.During the onset of lumbar kyphosis in patients with ankylosing spondylitis,the maximum stress of the annulus fibrosus and nucleus pulposus is located in the L1-L2 segment,which is fixed and will not alter with the change of body position.The late surgical treatment and correction of deformity should focus on releasing the pressure of the annulus fibrosus and nucleus pulposus in this segment to avoid the rupture of the annulus fibrosus and the injury of the nucleus pulposus.

BACKGROUND:Ankylosing spondylitis is a progressive inflammation of spinal stiffness deformity caused by tissue ossification and fibrosis.The posture of ankylosing spondylitis patients is abnormal and their activities are limited that minor injuries can lead to thoracolumbar fractures.Traditional medical image observation limits doctors'preoperative decision planning and postoperative disease prevention for ankylosing spondylitis treatment. OBJECTIVE:Based on the spinal model of ankylosing spondylitis patients before and after posterior spinal cancellous ossification osteotomy("Y"osteotomy for short),to explore the biomechanical changes of"Y"osteotomy and fixation in the treatment of ankylosing spondylitis. METHODS:Based on the preoperative and postoperative CT images of an ankylosing spondylitis patient who went to the Second Affiliated Hospital of Inner Mongolia Medical University,a three-dimensional spine model(T11-S1)before and after"Y"osteotomy(L3 osteotomy)was reconstructed in Mimics 19.0 software.A 7.5 Nm torque was applied to the top of T11 vertebral body to simulate the movement of the spine under six conditions:flexion,extension,left bending,right bending,left rotation and right rotation.Finally,the range of motion of each vertebral body,the stress of each intervertebral disc,and the stress of the screw rod system were simulated. RESULTS AND CONCLUSION:(1)After"Y"type osteotomy and posterior fixation,the range of motion of all vertebrae in the spine decreased,and the loss rate of upper vertebrae was large(L1:77.95%).(2)The maximum stress of the spinal intervertebral disc before operation occurred at the L1-L2 segment(0.55 MPa),and the maximum stress of the spinal intervertebral disc after operation occurred at the T11-T12 segment(0.50 MPa),and the stress of intervertebral disc below T12 was far less than that before operation.(3)The maximum stress of the screw rod system(166.67 MPa)occurred in the upper and middle segments of the rod body and the root of the pedicle screw.(4)In conclusion,the"Y"type posterior fixation operation enhances the stability of the spine and reduces the range of motion of the spine.The vertebral body decompression of the fixed segment is great and the stress-shielding phenomenon of the lower vertebral body is significant.The stiffness of the rod body and the stress concentration area of the pedicle screw should be strengthened to avoid the fracture of the rod caused by stress fatigue.

BACKGROUND:High ankle sprain is easily missed and leads to ankle dysfunction.Arthroscopy can detect hidden high ankle sprain.Suture-button elastic fixation can restore the biomechanical stability of the distal tibiofibular syndesmosis. OBJECTIVE:To explore the clinical efficacy of Suture-button elastic fixation for high ankle sprain under ankle arthroscopy. METHODS:A retrospective analysis was performed on 40 cases of high ankle sprain patients treated with Suture-button elastic fixation under ankle arthroscopy from August 2019 to August 2021 in the Department of Foot and Ankle Surgery,Wuhan Fourth Hospital.All patients underwent Suture-button elastic fixation.The American Orthopedic Foot and Ankle Society function score,Visual Analog Scale pain score,ankle range of motion,preoperative imaging data,and arthroscopic tibiofibular syndesmosis separation degree were recorded.Meislin criteria were used to evaluate the curative effect and postoperative complications were recorded. RESULTS AND CONCLUSION:(1)40 patients were followed up for 16-48 months after operation.(2)At the last follow-up,American Orthopedic Foot and Ankle Society score was(88.95±6.64 points).Visual Analog Scale score was(1.78±1.23 points).Ankle dorsiflexion range of motion was(33.50±5.79 degrees).Ankle plantarflexion range of motion was(34.50±5.97 degrees).There were statistically significant differences before and after surgery(P<0.05).(3)There was a low positive correlation between the radiographic separation index and the degree of arthroscopic separation(r=0.612,P<0.01).(4)The curative effect was evaluated by Meislin standard,with an excellent and good rate of 95%(38/40).Postoperative ankle joint pain was relieved,and ankle joint activities were significantly improved.(5)During the follow-up period,all patients had no nerve injury or incision infection.In 1 patient,the internal fixation was removed due to skin irritation and squatting sensation after operation.(6)It is concluded that Suture-button elastic fixation for high ankle sprain is effective under ankle arthroscopy in restoring ankle function and maintaining joint stability without the need for secondary removal,and it is worth clinical application.

Objective:To discuss the effect of the small ubiquitin-like modifier-specific protease 1(SENP-1)/hypoxia-inducible factor 1α(HIF-1α)pathway on chronic intermittent hypoxia(CIH)-induced vascular endothelial injury in the rats,and to clarify the related mechanism.Methods:The SD rats were randomly divided into control group and CIH group,and then the rats in each group were further divided into 2,4,and 6-week subgroups,and there were 8 rats in each subgroup.The rats in CIH group were exposed to CIH in a CIH chamber to induce CIH and create the obstructive sleep apnea hypopnea syndrome(OSAHS)models,while the rats in control group were exposed to normoxic conditions.The serum and thoracic aorta tissue of the rats in various groups were collected at each time point.HE staining was used to observe the thoracic aorta vascular injury of the rats in various groups;ELISA method was used to detect the levels of nitric oxide(NO),endothelin-1(ET-1),von Willebrand factor(vWF),and thrombomodulin(TM)in serum of the rats in various groups;Western blotting method was used to detect the expression levels of SENP-1,HIF-1α,and vascular endothelial growth factor A(VEGFA)proteins in thoracic aorta tissue of the rats in various groups.In vitro,the aortic endothelial cells(rAECs)of the rats were cultured and infected with SENP-1 shRNA adenovirus(sh-SENP-1)to construct the cell line with low expression of SENP-1.The CIH was used to induce the vascular endothelial cell injury,and the cells were divided into CIH group,CIH+sh-NC group,and CIH+sh-SENP-1 group;control group was set up separately.CCK-8 method was used to detect the proliferation activities of the cells in various groups;ELISA method was used to detect the activities of lactate dehydrogenase(LDH)in the supernatant and the levels of NO,ET-1,malondialdehyde(MDA),and activities of superoxide dismutase(SOD)in the cells in various groups;flow cytometry was used to detect the apoptotic rates of the cells in various groups;Western blotting method was used to detect the expression levels of SENP-1,HIF-1α,and VEGFA proteins in the cells in various groups.Results:With the extension of CIH induction time,compared with control group,the thoracic aorta endothelium in CIH group gradually became rough and significantly thickened,the level of serum NO of the rats in CIH group was decreased(P＜0.05),and the levels of serum ET-1,vWF,and TM,and the expression levels of SENP-1,HIF-1α,and VEGFA proteins in thoracic aorta tissue were increased(P＜0.05).Compared with control group,the proliferation activity of the cells in CIH group was decreased(P＜0.05),the LDH activity in the supernatant,the levels of ET-1,MDA,and the apoptotic rate in the cells were increased(P＜0.05),while the levels of NO and activity of SOD in the cells were decreased(P＜0.05),and the expression levels of SENP-1,HIF-1α,and VEGFA proteins in the cells were increased(P＜0.05).Compared with CIH group,the proliferation activity of cells in CIH+sh-SENP-1 group was increased(P＜0.05),the activity of LDH in the supernatant,the levels of ET-1,MDA,and the apoptotic rate of the cells were decreased(P＜0.05),while the level of NO and activity of SOD in the cells were increased(P＜0.05),and the expression levels of SENP-1,HIF-1α,and VEGFA proteins were decreased(P＜0.05).Conclusion:The SENP-1/HIF-1α pathway is highly activated in the thoracic aorta injury tissue of the rats induced by CIH.Silencing SENP-1 expression can reduce CIH-induced vascular endothelial cell injury,and its mechanism may be related to downregulating the activation level of SENP-1/HIF-1α pathway.

Objective:To analyze the effectiveness and interobserver agreement of the Parer five-tier, the National Institute of Child Health and Human Development (NICHD) three-tier, and the International Federation of Gynecology and Obstetrics (FIGO) three-tier electronic fetal monitoring (EFM) systems in identification of neonatal acidosis during labor.Methods:This retrospective study was conducted on full-term singleton cephalic deliveries with neonatal acidosis (umbilical artery blood gas pH≤7.1) and normal newborns (umbilical artery blood gas pH≥7.2) in the Nanjing Drum Tower Hospital, Nanjing University Medical School from January to December 2020. EFM tracings during the last 30-60 min before delivery were collected. Four obstetricians independently described the features of randomly sorted and coded EFM tracings. Another obstetrician categorized these tracings using the NICHD three-tier, FIGO three-tier, and Parer five-tier evaluation systems based on the features. All researchers were masked to the clinical characteristics and maternal and neonatal outcomes. The sensitivity and specificity for identifying neonatal acidosis, as well as the interobserver agreement, were analyzed for all three systems. Independent sample t-test, Chi-square (or Fisher's exact test) and Mann-Whitney U tests were used for statistical analysis. Inter-group comparisons of sensitivity and specificity between the three evaluation systems were assessed using McNemar's test. The Kappa statistic was used to analyze interobserver agreement. Results:This study included a total of 3 558 cases. After propensity score matching, there were 44 cases of neonatal acidosis and 78 control cases. There were no significant differences in parity, gestational weeks, modes of delivery, placental abruption, or analgesia rates between the two groups. The rates of instrumental vaginal delivery and neonatal intensive care unit (NICU) admission in the acidosis group were significantly higher than those in the control group [15.8% (7/44) vs. 2.6% (2/78), χ2=8.45, P=0.003; 31.8% (14/44) vs. 12.8% (10/78), χ2=8.45, P=0.004], while the umbilical artery blood pH and mean base excess were lower in the acidosis group than in the control group [7.04±0.07 vs. 7.30±0.05, t=4.98; (－12.40±3.32) vs. (－5.64±1.95) mmol/L, t=13.61; both P<0.001]. (2) Using the NICHD three-tier system, 95.5% (42/44) of the acidosis cases and 89.7% (70/78) of the control cases were classified as having category Ⅱ EFM tracings, indicating potential fetal acid-base imbalance; category Ⅲ EFM tracings were only observed in 4.5% (2/44) of the cases in the acidosis group. With the FIGO three-tier system, 81.8% (36/44) of the acidosis cases were categorized as having "pathological" tracings, and with the Parer five-tier system, 86.4% (38/44) of the acidosis cases were correctly classified into the "orange or red" risk zones that indicated acid-base imbalance. Among the control cases, there were 28.2% (22/78) with EFM tracings of "normal patterns" categorized by the FIGO three-tier system, and 41.0% (32/78) classified into the "green or blue" risk zones by the Parer five-tier system, which indicated good fetal conditions. None of the acidosis cases were misdiagnosed as being normal by the Parer five-tier system. (3) Compared with the NICHD three-tier system, both the FIGO three-tier and the Parer five-tier systems showed increased diagnostic sensitivity [4.5% (1.2%- 14.5%) vs. 81.8% (66.8%-89.4%) and 86.4% (71.8%-92.4%)], but decreased specificity [100.0% (95.3%- 100.0%) vs. 87.2% (78.0%-92.9%) and 84.6% (75.0%-91.0%)]. There was no statistically significant difference in the sensitivity or specificity between the FIGO three-tier and Parer five-tier systems for identifying neonatal acidosis ( P=0.727 and 0.791). (4) When reading the tracings of control cases, the total agreement rate for the NICHD three-tier system by different observers was as high as 94.2%, while the total agreement rates for the FIGO three-tier and Parer five-tier systems were 69.7% and 67.7%, respectively. In the interpretation of EFHR tracings for acidosis cases, the interobserver agreement for the Parer five-tier system was excellent [Kappa (95% CI): 0.87 (0.79-0.95)], while both the NICHD three-tier and FIGO three-tier systems showed good agreement [Kappa (95% CI): 0.77 (0.66-0.88) and 0.72 (0.60-0.84)]. Conclusions:The Parer five-tier and the FIGO three-tier systems have higher sensitivity in identifying neonatal acidosis than the NICHD three-tier system, and the Parer five-tier system achieves a higher negative predictive value and a greater agreement in the interpretation of pathological EFM patterns.