Objective:This study aims to explore clinical subtypes of Garden typeⅠfemoral neck fractures and develop corresponding reduction strategies based on the characteristics of the fractures.Methods:A retrospective analysis was conducted on the data of 256 patients with Garden type I femoral neck fractures admitted to Tianjin Hospital from January 2015 to January 2018. There were 89 males and 167 females included, with a mean age of 56.5±12.8 years (range, 17-86 years), and with 159 on the left side and 97 on the right side. According to the anteroposterior and lateral X-ray images, the fractures were further classified into two subtypes: 111 cases of Garden type I a (simple abduction without hypsokinesis of the femoral head), characterized by abduction and impaction of the femoral head on anteroposterior images, and no obvious hypsokinesis of the femoral head or only central impaction of the femoral head on lateral images; 145 cases of Garden I b type (femoral head abduction with hypsokinesis), characterized by abduction and impaction of the femoral head on anteroposterior images, and remarkable hypsokinesis on lateral images. The injury mechanism of type I a involved abduction and impaction caused by the violent extension, abduction, and external rotation of the hip joint. Mild flexion and adduction of the hip joint can be used to reduce the abduction and impaction. The injury mechanism of type I b is similar to type Ia in the first stage, but the violence continues to increase and leading to significant hypsokinesis of the femoral head. Reduction was achieved by excessive flexion, adduction, and mild internal rotation, tilting the femoral head backward to facilitate reduction. The surgical strategy were close reduction and cannulated screw fixation (three cannulated screws in an "inverted triangle" arrangement). Postoperatively, anteroposterior and lateral X-rays were taken immediately to assess the quality of reduction, including the Garden index, Lowell "S" curve, and screw placement. During follow-up, fracture healing and complications were recorded, and Harris score was used to evaluate hip joint function at the final follow-up.Results:All patients successfully received operative therapy and were followed up with a mean of 7.1±1.9 years (range, 5-10 years). Garden index showed 91.4%(234/256) achieved anatomical reduction, with an excellent reduction rate of 97.3%(249/256). The excellent rate of the Lowell "S" curve was 97.7%(250/256), and the excellent and good rate for screw insertion was 98.8%(253/256). All patients achieved primary fracture healing without infection, nonunion of fractures, failure of internal fixation, or other complications. Two patitents with Garden I b fractures (0.8%) developed femoral head necrosis due to premature weight-bearing at 9 and 12 months postoperatively, respectively, after fracture healing. However, with strict hip preservation treatment, their symptoms resolved without further progression of necrosis or need for reoperation. At the final follow-up, the mean Harris score was 93.9±4.5 points (range, 81-100 points), with an excellent and good rate of 98.8%(253/256).Conclusions:Garden I femoral neck fractures can be categorized into two subtypes based on their characteristics and injury mechanisms. Adopting corresponding reduction methods according to subtypes can achieve anatomical reduction and favorable early to mid-stage therapeutic outcomes (primary fracture healing and low incidence of femoral head necrosis).

Objective:This study aims to explore clinical subtypes of Garden typeⅠfemoral neck fractures and develop corresponding reduction strategies based on the characteristics of the fractures.Methods:A retrospective analysis was conducted on the data of 256 patients with Garden type I femoral neck fractures admitted to Tianjin Hospital from January 2015 to January 2018. There were 89 males and 167 females included, with a mean age of 56.5±12.8 years (range, 17-86 years), and with 159 on the left side and 97 on the right side. According to the anteroposterior and lateral X-ray images, the fractures were further classified into two subtypes: 111 cases of Garden type I a (simple abduction without hypsokinesis of the femoral head), characterized by abduction and impaction of the femoral head on anteroposterior images, and no obvious hypsokinesis of the femoral head or only central impaction of the femoral head on lateral images; 145 cases of Garden I b type (femoral head abduction with hypsokinesis), characterized by abduction and impaction of the femoral head on anteroposterior images, and remarkable hypsokinesis on lateral images. The injury mechanism of type I a involved abduction and impaction caused by the violent extension, abduction, and external rotation of the hip joint. Mild flexion and adduction of the hip joint can be used to reduce the abduction and impaction. The injury mechanism of type I b is similar to type Ia in the first stage, but the violence continues to increase and leading to significant hypsokinesis of the femoral head. Reduction was achieved by excessive flexion, adduction, and mild internal rotation, tilting the femoral head backward to facilitate reduction. The surgical strategy were close reduction and cannulated screw fixation (three cannulated screws in an "inverted triangle" arrangement). Postoperatively, anteroposterior and lateral X-rays were taken immediately to assess the quality of reduction, including the Garden index, Lowell "S" curve, and screw placement. During follow-up, fracture healing and complications were recorded, and Harris score was used to evaluate hip joint function at the final follow-up.Results:All patients successfully received operative therapy and were followed up with a mean of 7.1±1.9 years (range, 5-10 years). Garden index showed 91.4%(234/256) achieved anatomical reduction, with an excellent reduction rate of 97.3%(249/256). The excellent rate of the Lowell "S" curve was 97.7%(250/256), and the excellent and good rate for screw insertion was 98.8%(253/256). All patients achieved primary fracture healing without infection, nonunion of fractures, failure of internal fixation, or other complications. Two patitents with Garden I b fractures (0.8%) developed femoral head necrosis due to premature weight-bearing at 9 and 12 months postoperatively, respectively, after fracture healing. However, with strict hip preservation treatment, their symptoms resolved without further progression of necrosis or need for reoperation. At the final follow-up, the mean Harris score was 93.9±4.5 points (range, 81-100 points), with an excellent and good rate of 98.8%(253/256).Conclusions:Garden I femoral neck fractures can be categorized into two subtypes based on their characteristics and injury mechanisms. Adopting corresponding reduction methods according to subtypes can achieve anatomical reduction and favorable early to mid-stage therapeutic outcomes (primary fracture healing and low incidence of femoral head necrosis).

Objective:To explore the relationships among the activity level of coagulation factor XII (FXII), coagulation function indexes, polymorphisms of F12 gene loci rs17876030 and rs1801020, as well as their correlations with deep venous thrombosis (DVT) in fracture patients. Methods:A case-cohort control study was conducted. 200 fracture patients diagnosed and treated in the Department of Traumatic Orthopedics of Tianjin Hospital from September 2015 to September 2023 were included. They received routine anticoagulant prophylaxis for DVT treatment but still developed DVT during hospitalization (thrombus group). 100 fracture patients hospitalized during the same period without DVT under the same anticoagulant strategy were matched (non-thrombus group). 100 healthy people who underwent physical examinations in the outpatient department of Tianjin Hospital during the same period were also matched (normal group). Plasma samples of all subjects were collected. Laboratory tests were performed to measure activated partial thromboplastin time (APTT), prothrombin time (PT), thrombin time (TT), fibrinogen (Fg), D-Dimer. The activity level of FXII was detected by the one-stage fixation method, the antigen of FXII was detected by enzyme-linked immunosorbent assay, and the polymorphisms of F12 gene loci rs17876030 and rs1801020 were detected by direct sequencing method. The relationships among various detection indexes and their correlations with DVT were analyzed. Results:There were no statistically significant differences in APTT, PT, and TT among the thrombus group, non-thrombus group, and normal group ( F=0.748, P=0.483; F=0.092, P=0.840; F=0.031, P=0.660). The Fg in the thrombus group was 4.5±2.4 g/L and D-Dimer was 786.2±234.9 mg/L, which were statistically different from 2.9±1.8 g/L and 261.3±165.5 mg/L in the non-thrombus group and 2.2±1.1 g/L and 198.1±96.4 mg/L in the normal group respectively ( F=3.473, P=0.046; F=34.960, P<0.001; P<0.05). The activity of FⅫ in the thrombus group was 78.3%±21.9%, which was statistically different from 97.8%±31.4% in the non-thrombus group and 94.5%±35.7% in the normal group ( F=3.581, P=0.032; P<0.05). The activity of FXII was negatively correlated with APTT ( r=-0.149, P=0.035). In the thrombus group, there were 122 cases (61.0%) with the TT genotype of rs17876030, which was statistically different from 34 cases (34.0%) in the non-thrombus group and 30 cases (30.0%) in the normal group (χ 2=12.630, P=0.002). In the thrombus group, there were 115 cases (57.5%) with the CC genotype of rs1801020, which was statistically different from 25 cases (25.0%) in the non-thrombus group and 16 cases (16.0%) in the normal group (χ 2=26.820, P<0.001). The activity levels of FXII of the TT genotype of rs17876030 in the thrombus group, non-thrombus group, and normal group were lower than those of the CC and CT genotypes, and the differences were statistically significant ( F=27.130, P<0.001; F=18.384, P<0.001; F=12.830, P=0.001; P<0.05). The activity levels of FXII of the CC genotype of rs1801020 in the three groups were lower than those of the TT and CT genotypes, and the differences were statistically significant ( F=38.631, P<0.001; F=23.562, P<0.001; F=25.829, P<0.001; P<0.05). The proportion of the TT genotype of rs17876030 was the highest in the thrombus group, and the activity level of FⅫ in patients with this genotype was lower. The TT genotype of rs17876030 was related to DVT ( r=-0.831, P=0.043). The proportion of the CC genotype of rs1801020 was the highest in the thrombus group, and the activity level of FⅫ in patients with this genotype was lower. The CC genotype of rs1801020 was related to DVT ( r=-0.784, P=0.040). Conclusion:Fg and D-Dimer are related to DVT. The activity level of FXII is negatively correlated with APTT. Prolonged APTT suggests the possibility of FⅫ deficiency, and the decreased activity level of FXII may be related to DVT.

Objective:To explore the relationships among the activity level of coagulation factor XII (FXII), coagulation function indexes, polymorphisms of F12 gene loci rs17876030 and rs1801020, as well as their correlations with deep venous thrombosis (DVT) in fracture patients. Methods:A case-cohort control study was conducted. 200 fracture patients diagnosed and treated in the Department of Traumatic Orthopedics of Tianjin Hospital from September 2015 to September 2023 were included. They received routine anticoagulant prophylaxis for DVT treatment but still developed DVT during hospitalization (thrombus group). 100 fracture patients hospitalized during the same period without DVT under the same anticoagulant strategy were matched (non-thrombus group). 100 healthy people who underwent physical examinations in the outpatient department of Tianjin Hospital during the same period were also matched (normal group). Plasma samples of all subjects were collected. Laboratory tests were performed to measure activated partial thromboplastin time (APTT), prothrombin time (PT), thrombin time (TT), fibrinogen (Fg), D-Dimer. The activity level of FXII was detected by the one-stage fixation method, the antigen of FXII was detected by enzyme-linked immunosorbent assay, and the polymorphisms of F12 gene loci rs17876030 and rs1801020 were detected by direct sequencing method. The relationships among various detection indexes and their correlations with DVT were analyzed. Results:There were no statistically significant differences in APTT, PT, and TT among the thrombus group, non-thrombus group, and normal group ( F=0.748, P=0.483; F=0.092, P=0.840; F=0.031, P=0.660). The Fg in the thrombus group was 4.5±2.4 g/L and D-Dimer was 786.2±234.9 mg/L, which were statistically different from 2.9±1.8 g/L and 261.3±165.5 mg/L in the non-thrombus group and 2.2±1.1 g/L and 198.1±96.4 mg/L in the normal group respectively ( F=3.473, P=0.046; F=34.960, P<0.001; P<0.05). The activity of FⅫ in the thrombus group was 78.3%±21.9%, which was statistically different from 97.8%±31.4% in the non-thrombus group and 94.5%±35.7% in the normal group ( F=3.581, P=0.032; P<0.05). The activity of FXII was negatively correlated with APTT ( r=-0.149, P=0.035). In the thrombus group, there were 122 cases (61.0%) with the TT genotype of rs17876030, which was statistically different from 34 cases (34.0%) in the non-thrombus group and 30 cases (30.0%) in the normal group (χ 2=12.630, P=0.002). In the thrombus group, there were 115 cases (57.5%) with the CC genotype of rs1801020, which was statistically different from 25 cases (25.0%) in the non-thrombus group and 16 cases (16.0%) in the normal group (χ 2=26.820, P<0.001). The activity levels of FXII of the TT genotype of rs17876030 in the thrombus group, non-thrombus group, and normal group were lower than those of the CC and CT genotypes, and the differences were statistically significant ( F=27.130, P<0.001; F=18.384, P<0.001; F=12.830, P=0.001; P<0.05). The activity levels of FXII of the CC genotype of rs1801020 in the three groups were lower than those of the TT and CT genotypes, and the differences were statistically significant ( F=38.631, P<0.001; F=23.562, P<0.001; F=25.829, P<0.001; P<0.05). The proportion of the TT genotype of rs17876030 was the highest in the thrombus group, and the activity level of FⅫ in patients with this genotype was lower. The TT genotype of rs17876030 was related to DVT ( r=-0.831, P=0.043). The proportion of the CC genotype of rs1801020 was the highest in the thrombus group, and the activity level of FⅫ in patients with this genotype was lower. The CC genotype of rs1801020 was related to DVT ( r=-0.784, P=0.040). Conclusion:Fg and D-Dimer are related to DVT. The activity level of FXII is negatively correlated with APTT. Prolonged APTT suggests the possibility of FⅫ deficiency, and the decreased activity level of FXII may be related to DVT.

Objective:To analyze the risk factors of acute kidney injury (AKI) in hip fracture patients with serious underlying diseases and establish a prediction nomogram.Methods:Clinical information of hip fracture patients admitted to the intensive care unit (ICU) of Beth Israel Deaconess Medical Center (BIDMC) was analyzed using the Medical Information Mart for Intensive Care (MIMIC)-IV. Patient comorbidities, disease scores, vital signs and laboratory tests, surgical modalities, invasive procedures, and drug use were recorded. According to the diagnostic criteria of AKI in the Kidney Disease Improving Global Outcome (KDIGO) guideline, the enrolled patients were randomly divided into training set and validation set. Based on logistic regression analysis, least absolute shrinkage and selection operator (LASSO) logistic regression algorithm was used to analyze the risk factors of AKI after admission, and the corresponding prediction model was calculated.Results:A total of 474 patients were enrolled, including 331 in the training set and 143 in the validation set. According to the diagnostic criteria of AKI of KDIGO guidelines, the patients were divided into AKI group (159 cases) and non-AKI group (172 cases). Univariate analysis showed that age ( t=2.61, P=0.009), coronary heart disease (χ 2=2.08, P=0.038), heart failure (χ 2=2.60, P=0.009), hemoglobin ( t=1.89, P=0.059), platelets ( t=1.81, P=0.070), urea nitrogen ( t=2.83, P=0.005), blood creatinine ( t=3.65, P<0.001), blood sodium ( t=2.55, P=0.011), blood glucose ( t=2.52, P=0.012), anion gap ( t=3.44, P=0.001), diastolic blood pressure ( t=2.72, P=0.007), mean arterial pressure ( t=2.16, P=0.031), SOFA score ( t=3.69, P<0.001), simplified acute physiological function score II (SAPSII) score ( t=2.95, P=0.003), as well as furosemide (χ 2=2.03, P=0.042), vancomycin (χ 2=1.70, P=0.089), vasoactive medications (χ 2=3.74, P<0.001) and use of invasive mechanical ventilation (χ 2=4.81, P<0.001) were risk factors associated with the development of AKI in hip fracture patients. Multivariate logistic regression analysis showed that age ( OR=1.03, P<0.001), coronary heart disease ( OR=2.05, P=0.069), hemoglobin ( OR=0.88, P=0.050), blood creatinine ( OR=1.37, P=0.009), blood sodium ( OR=1.07, P=0.026), anion gap ( OR=1.09, P=0.028) and vasoactive medications ( OR=3.83, P=0.018) and the use of invasive mechanical ventilation ( OR=6.56, P<0.001) were independent predictors of the development of AKI in hip fracture patients with serious underlying diseases. The area under the curve of the nomogram prediction model constructed by the above 8 predictors was 0.789, and the calibration curve of the nomogram was close to the ideal diagonal. Decision curve analysis showed that the net benefit of the model was significant. Conclusion:The incidence of AKI is high in hip fracture patients with serious underlying diseases. Age, coronary heart disease, hemoglobin, serum creatinine, serum sodium, anion gap, vasoactive drugs, and invasive mechanical ventilation can predict the occurrence of AKI to a certain extent. Combined with the risk factors, the construction of the corresponding prediction model can predict and manage the diagnosis and treatment of AKI in patients with hip fracture complicated with severe underlying diseases.

Objective:To investigate the early effects of cup in cup technique in reconstructing paprosky III acetabular bone defect in revision hip arthroplasty.Methods:From January 2017 to December 2019, a total of 20 cases (20 hips) with paprosky III acetabular bone defect were reconstructed by Cup-in-Cup technique, including 9 males and 11 females. The age ranged from 45 to 76 years, with an average of 64.6 years. The causes of revision were aseptic loosening of prosthesis in 17 cases and loosening of prosthesis caused by periprosthetic infection in 3 cases. There were 13 hips with acetabular bone defect of paprosky IIIA and 7 hips with paprosky IIIB. The acetabular side was repaired in 13 cases, and the acetabulum and femoral side were repaired in 7 cases at the same time. Harris hip score was used to evaluate hip function during postoperative follow-up. The occurrence of serious complications such as intraoperative vascular and nerve injury, postoperative prosthesis dislocation, periprosthetic infection and fracture were counted. The height and horizontal position of hip rotation center were measured by X-ray film.Results:The operation duration was 110±25 min (range 80-180 min) and intraoperative bleeding was 700±180 ml. All cases were followed up for 12-36 months, with an average of 18 months. At the last follow-up, the Harris hip score of 16 cases was more than 80, with excellen in 2 cases, good in 14 cases and fair in 4 cases. The Harris score was 84.3±7.5, which was significantly higher than that before operation 40.1±16.6 ( t=15.34, P<0.001). The height of hip joint rotation center on the affected side decreased from 34.2± 3.3 mm before operation to 18.6±2.8 mm after operation with significant difference ( t=15.11, P<0.001). The horizontal distance increased from 18.1±5.5 mm before operation to 26.2±7.3 mm after operation with significant difference ( t=-5.95, P<0.001). After operation, the height of hip joint rotation center on the affected side was slightly higher than that on the opposite side, with a significant difference between the affected side 18.6±2.8 mm and the opposite side 12.2±3.3 mm ( t=6.73, P=0.018). The horizontal position was 26.2±7.3 mm, which had no significant difference compared with the contralateral 30.1±5.5 mm ( t=-3.29, P=0.381). There was no vascular and nerve injury, periprosthetic infection or incision related complications. During the following-up, the prosthesis was in satisfied position without prosthesis or screw loosening and fracture. Conclusion:The reconstruction of paprosky III acetabular bone defect with Cup-in-Cup technique in revision hip arthroplasty can obtain satisfied early effects, with achieving relatively normal hip rotation center and initial stability.

Bisphosphonates have become the first-line drugs for the treatment of osteoporosis,which can reduce the risk of brittle fracture by inhibiting osteoclast activity and increasing bone density.Bisphosphonates bring benefits to osteoporosis patients,while some side effects can occur.In recent years,bisphosphonate related femoral atypical fractures (AFF) have been gradually recognized and become the focus of researches.AFF has typical clinical features and X-ray findings:Patients with long-term usage of bisphosphonate drug.AFF were defined as atraumatic or low-trauma fractures located in the subtrochanteric region or femoral shaft.X-ray showed transverse or short oblique fracture of the medial cortex which shaped like a "spike",and the bone cortex at the fracture area becomes thicker because of localized or diffuse periosteal reaction.AFF pathological mechanism is not clear,mainly with long-term use of bisphosphonates which seriously inhibit bone turnover,other theories including the theory of syndrome like collagen abnormal theory,mineral abnormal theory,hypophosphatasia,precise pathological mechanism still needs further study.Although the absolute incidence of AFF is very low,the number of AFF will inevitably increase with the increasing number of aging osteoporosis patients and the widespread application of bisphosphonates,which should be paid more attention to.AFF risk factors included long-term usage history of bisphosphonate,glucocorticoid treatment history,female patients,fracture prodromal symptoms including pain,discomfort or weakness in the thighs or groin and the bowing of the femoral shaft was associated with the location of AFF fracture.At present,the point of view of AFF treatment is:complete fracture of femoral length,reamed intramedullary nail fixation.Even for incomplete fractures,preventive intramedullary nailing should also be considered.The healing time of AFF fracture increases obviously.The most common complications are delayed union and nonunion.The rate of delayed union can be as high as 26％.How to improve the curative effect of this kind of fracture needs further study.In this paper,the latest literature on the clinical features,diagnostic criteria,morbidity,risk factors,pathological mechanisms,treatment and complications of atypical fractures of the femur were reviewed.

Objective To investigate the clinical effects of high restrictive anti-dislocation prosthesis total hip arthroplasty(THA)in treating elderly femoral neck fracture patients with hemiplegia.Methods From June 2015 to January 2017,Fortythree elderly femoral neck fracture patients with hemiplegia were treated with CombiCup THA system.There were 15 males and 28 females with an average age of 71.5±5.6 years (60-84 years).The left side was involved in 20 cases,while the right side in 23 cases.There were 15 cases with Garden Ⅲ type and 28 cases with type Ⅳ.Lower limb muscle strength grade were 20 cases in grade 3,19 cases in grade 4,and 5 cases in grade 5.Sixteen cases walked independently before injury,while 27 of them walked with the aid of crutches.The duration between injuries to operation ranged from 2 days to 5 days.The size of the prosthesis and offset distance were recorded by template technique pre-operation.The appropriate type of prosthesis was selected to restore the offset and to reconstruct the abductor muscle arm,according to the actual measurement in the operation and the preoperative plan.Based on the bone mineral density and medullary cavity morphology,biological or cemented femoral stem prosthesis was selected.The quality of the implant and the length of both lower limbs were evaluated by pelvic X-ray immediately after operation.The patients were followed-up at 2 weeks,1 months,2 months,3 months,6 months,1 and 2 years.Functional exercise guidance and complications were recorded at the follow-up duration.At the last follow-up,the hip function and limb function were evaluated according to the Harris score and Fugl-Meyer motor function assessment respectively.Results Based on pelvic X-ray evaluation after operation,all prosthesis position were favorable with the average angle of acetabular abduction 45.1±2.3 degrees and the length difference of both limbs less than 5 mm (average 2.2±0.8 mm).The follow-up duration ranged from 6 to 24 months with an average of 11.2±3.5 months.There was no complication such as prosthesis dislocation and infection.Deep venous thrombosis in calf occurred in 3 patients at 2 days after operation,who underwent recanalization after thrombolysis.At the last follow-up,the average score of Harris hip function and Fugl-Meyer were 90.2±3.8 (77 to 96) and 97.1±2.5 (83 to 100),respectively.No dislocation,infection,loosening,subsidence and osteolysis phenomenon was found during the follow-up.Conclusion The elderly patients with Garden type Ⅲ or Ⅳ femoral neck fractures accompanied with hemiplegia can be treated with anti-dislocation prosthesis THA.It does have the advantages of low dislocation rate and imoroved hemiolegic limb function.

Objective To investigate the mechanism,injury characteristics,and early interventions of bilateral femoral shaft fracture.Methods Twenty-five cases of bilateral femoral shaft fracture treated between December 2009 and June 2012 were enrolled in the study.Eighteen patients were males and 7 were females with mean age of 31.2 years (range,17-40 years).Nineteen cases were injured due to traffic accidents and 6 due to the hit by heavy objects.There were 47 sides with closed fracture and 3 sides with open fracture.Intramedullary nailing was performed at 32 sides and plate fixation was used at 18 sides.ISS,blood routine,some blood biochemical items,blood or plasma use,and hospitalization days were measured.Results ISS was (14.6 ± 5.2) points.Preoperative readiness time and hospital stay were (10.1 ± 3.7) days and (28.9 ± 8.4) days respectively.After hospitalization,measured values were (3.0 ± 0.4) × l012/L for red blood cells,(86.0 ± 13.5) g/L for hemogIobin,(47.0 ± 10.6) g/L for total protein,(31.4 ± 6.5) g/L for albumin,(124.1 ± 95.1) U/L for aspartate aminotransferase,(114.2 ± 107.1) U/L for alanine aminotransferase,and (1 848.7 ± 1 044.8) U/L for creatine kinase with significant differences from the reference ranges (P ＜ 0.05 or 0.01).Amount of blood transfused for 23 cases was (1 444.4 t 726.5) ml and plasma transfused for 19 cases was (305.6 ± 98.3) ml before operation.Volume of intra-and post-operative blood transfusion was (2 005.7 ± 1 153.1) ml.Conclusions Stabilization of vital signs predominates the early treatment of bilateral femoral shaft fracture.After the condition is stable,intramedulary nailing or plating can be performed concurrently.

Objective To investigate the possibility of establishing a Modic changes (MCs) animal model,and explore the pathogenesis of MCs through imaging,histology and molecular biology experiments.Methods Fifty four New Zealand rabbits (weight 2.5-3.0 kg,half male and half female) were randomly divided into 3 groups:sham group (n=l8),muscle embedment group (n=18) and NP embedment group (n=18).In NP embedment group,the L4-5 and L5-6 discs were exposed by the lumbar anterolateral surgical approach.A 16 G needle was used to puncture the L5-6 vertebral body close to the epiphyseal plate.The depth of the drilling was approximately 3 mm.A 5 ml syringe was then put into the L4-5 intervertebral disc and extracted the NP,which was injected into the drilled hole of the vertebral body.The muscle embedment group and sham group shared the same operating procedures and drilling methods with the NP embedment group.Some pieces of muscle acquired from paraspinal muscles were put into the drilled hole in muscle embedment group,while nothing was put into the drilled hole in sham group.After that,the bleeding stopping,tissue washing and suture were done in all groups.12 weeks,16 weeks and 20 weeks after the surgery,MRI scan was applied to each group.All the specimens were tested by HE staining,real-time fluorescence quantitative PCR and Western blot to observe the expression of inflammatory cytokines.Results After modeling for 12 weeks,16 weeks and 20 weeks,MRI showed low signal changes on T1WI and mixed high signal in the context of low signal changes on T2WI in the NP embedment group.However,the muscle embedment and sham group showed no significant signal changes.Gross observation and HE staining confirmed that there was abnormal tissue proliferation in the imbed site of the NP embedment group.RT-PCR and Western blot showed high expression of IL-4,IL-17 and IFN-γin the NP embedment group,which were positively correlated with the length of the postoperative period.There was no significant difference between the muscle embedment group and sham group.Conclusion The puncturing of vertebral body close to endplate and putting nucleus into it can create an animal model of MCs.Autoimmune factors may play an important role in MCs.