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Objective To study the biomechanical performance of proximal femoral nailing antirotation (PFNA) in the treatment of femoral intertrochanteric fracture involving the lateral wall using finite element analysis and the significance of the lateral wall.Methods A healthy senior volunteer,male,80 years of age,was recruited for this study.The CT data of his proximal femur were used to establish a three-dimensional finite element model of proximal femur by software Mimics17.0 and Geomagic Stusio.After the intertrochanteric fracture of AO-type 31-A1.2 was simulated together with coronal displacement of the lateral wall fracture,it was assembled with PFNA into the three-dimensional finite element model.Finite element analysis was performed on the femoral head,neck,fracture ends,lateral wall,and internal components of the model to observe the stress values of various parts of the model under the same load,with different degrees of fracture reduction (no displacement,anterior displacement of 5％,10％,15％ and 20％,posterior displacement of 5％,10％,15％ and 20％) and with or without the lateral wall.Results The stress values for internal components at the femoral head,neck,fracture ends,main nail with anatomical reduction of fracture ends and integrity of the lateral wall were 0.40 MPa,30.05 MPa,74.35 MPa and 121.68 MPa,respectively.The respective stress values of the above with lateral wall fracture were 0.82 MPa,47.32 MPa,151.92 MPa and 266.88 MPa,increased by about 100％.With every horizontal reduction loss increased by 5％ forward or backward,the stress exerting on the corresponding spots would see a 10％ progressive growth,plus 20％ lateral wall fracture and reduction loss.The stress of the main nail (468.43 MPa) was thrice that (121.68 MPa) of the stress posing on the complete lateral wall with the fracture ends 100％ reduced.Conclusions When PFNA is used in the treatment of femoral intertrochanteric fractures involving the lateral wall,stresses on the internal components may be doubled.Loss of coronal reduction may lead to the most significant increase in stress on the bonding site between the main nail and screw blade.
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Objective To compare the curative effects of Pauwels cannulated screws (PCS) and DHS-blade plus anti-rotation screw +anti-rotation screw(DHSA +AS) in the treatment of Pauwels type Ⅲ femoral neck fractures.Methods From December 2013 to December 2015,46 patients with fresh Pauwels type Ⅲ femoral neck fracture were treated with internal fixation at our department.They were divided into 2 groups according to different fixation methods.In the DHSA + AS group of 25 patients,13 were male and 12 female,with an average age of 49.2 ± 8.2 years,and there were 3 cases of Garden type Ⅱ,4 cases of Garden type Ⅲ and 18 cases of Garden type Ⅳ.In the PCS Group of 21 patients,11 were male and 10 female,with an average age of 48.7 ± 6.2 years,and there were 2 cases of Garden type Ⅱ,6 cases of Garden type Ⅲ and 13 cases of Garden type Ⅳ.The 2 groups were compared in terms of operation time,intraoperative blood loss,reduction quality,hospital stay,union time,postoperative complications and Harris hip score.Results DHSA + AS group needed significantly longer operation time (54.0 ± 7.3 minutes) and incurred significantly more intraoperative blood loss (102.3 ± 10.5 mL) than PCS group (46.3 ± 5.4 minutes & 77.4 ±9.1 mL,respectively) (P ＜ 0.05).There were no significant differences between the 2 groups in reduction quality,hospital stay,or union time (P ＞ 0.05).DHSA + AS group and PCS group obtained an average follow-up of 14.1 ± 1.6 months and 13.7 ± 1.2 months,respectively.For DHSA + AS group and PCS group,the rate of postoperative complications was respectively 12.0％ (3/25) versus 4.8％ (1/91),and the Harris hip score at the last follow-up respectively 83.6 ± 5.4 versus 85.1 ± 5.5,showing no significant differences between the 2 groups (P ＞ 0.05).Conclusions DHSA + AS and PCS are both suitable internal fixation options for patients with Pauwels type Ⅲ femoral neck fracture when reduction is fine.Compared with DHSA + AS,PCS may need less operation time and incur less intraoperative blood loss.
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Objective To investigate the surgical strategies for management of unstable fractures of intertrochanteric lateral wall.Methods From July 2012 to June 2014,50 patients with unstable fractures of intertrochanteric lateral wall received osteosynthesis with proximal femoral nail anti-rotation.They were 37 men and 13 women,with an average age of 65.6 years (range,from 42 to 87 years).According to our morphology classification,25 patients belonged to type Ⅰ (comminuted fracture of lateral wall),4 to type Ⅱ (split fracture of lateral wall with loss of medial support),21 to type Ⅲ (comminuted fracture of lateral wall and subtrochanteric part with loss of medial support).The fractures were managed differently according to our classification.Type Ⅰ were treated by intramedullary fixation with compression screws to reconstruct the lateral wall,type Ⅱ by intramedullary fixation after reconstruction of the lateral wall lby cables,and type Ⅲ by intramedullary fixation after optimal reduction of the coronal plane and neck-shaft angle because the lateral wall could not be reconstructed.Results The 50 patients obtained an average follow-up of 17 months (range,from 5 to 24 months).No deep infection or wound dehiscence happened.Deep vein thrombosis occurred in 2 patients.No nonunion,cutout of the sliding screw,or coxa vara occurred.The operation time,blood loss,time of weight loading after operation and time of union increased with our increased classification.One patient died from a heart disease 5 months after operation.Functional outcome of the other 49 patient was assessed by Harris hip score one year after operation.Forty patients were excellent,6 good and 3 fair,giving an excellent to good rate of 93.9％.Conclusion Unstable fractures of intertrochanteric lateral wall should be treated using different surgical strategies based on the morphology classification system.
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Objective To evaluate effect of construction with dual plates via olecranon osteotomy approach in treatment of type C distal humeral fractures.Methods The study involved 19 patients with type C distal humeral fractures treated by olecranon osteotomy and double plate fixation between July 2008 and April 2010,including 11 males and 8 females at a mean age of 49.2 years (range,27-71 years).Fractures were causes by traffic accidents in 10 patients,tumble in seven and fall from height in two.According to Association for Osteosynthesis/Orthopaedic Trauma Association (AO/OTA) classification,there were nine patients with type C2 and 10 with type C3 fractures.Besides,two patients were complicated by ulnar nerve injuries and one by radial nerve injury.Results Primary wound healing was achieved in all patients after operation.All patients were followed up for average 15.9 months (range,12-20 months).X-ray films revealed that both fracture and olecranon osteotomy sites were healed in average 12 weeks (range,8-18 weeks).No fixation failure,myositis ossificans,malunion,delayed union or disunion occurred during the follow-up.Average Mayo elbow performance score (MEPS) was 94.8 points (range,75-100 points) at the last follow-up,which showed excellent results in 14 patients,good in three,and fair in two,with excellence rate of 90％.Conclusions Double plate fixation via olecranon osteotomy gains advantages of solid fixation and early functional exercise in treatment of comminuted intercondylar fractures of humerus.Moreover,postoperative outcome is satisfactory.
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Objective To evaluate the safety, feasibility and efficacy of CT-guided percutaneous hollow screw fixation in the treatment of patients with sacroiliac complex injury. Methods Forty-five patients (at age range of 15-58 years) with sacroiliac complex injuries including 20 males and 25 females were enrolled in this study. There were 28 traffic injuries and 17 fall injuries. Fourteen patients with sacral fractures ( 15 patients with Dennis type Ⅰ fractures and nine with Dennis type Ⅱ fractures), 12 with sacroiliac joint dislocation, six with sacral fracture combined with sacroiliac joint dislocation and nine with sacroiliac joint complex injury. All patients were treated by CT-guided percutaneous hollow screw fixation. The functional exercise was performed early after operation. Results Seventy-two hollow screws were installed in 45 patients, with the operation time for 21-68 minutes ( average 37 minutes) and the operative blood loss for 30-75 ml. Of all, 38 patients were followed up for 6-26 months. According to the Majeed functional criteria, the score of the patients was 72-96 points (average 90. 3 points ), which showed that the results were excellent in 33 patients and good in two, with excellence rate of 92%. No iatrogenic nerve injury, incision infection or screw fracture were detected. Conclusion CT-guided percutaneous hollow screw fixation takes advantages of precise direction, stable fixation and safe operation and hence is one of safe and effective methods for treatment of sacroiliac complex injury.
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BACKGROUND: As a pain-related peptide, substance P is closely related with sustained pain in low back and lower extremities caused by lumbar spinal stenosis. However, the expression of substance P in the rat with cauda equina compression rat is not reported.OBJECTIVE: To investigate the content of substance P in spinal cord of rat with lumbar spinal stenosis at different stages.DESIGN: A randomized and controlled experimental study.SETTING: The Orthopedic Department of the First Affiliated Hospital of China Medical University.MATERIALS: The trial was conducted in the Experimental Animal Center of China Medical University within the period from February 2003 to December 2004. Thirty mature male SD rats were randomly and averagely assigned into five groups. One group served as control and in the other four experimental groups the content of substance P of the rats were examined in the 2nd, 4th, 8th and 12th respect week respectively.METHODS: The model of lumbar spinal stenosis was established by compressing cauda equina in rats. The spinal cords were harvested in the 2nd,4th, 8th and 12th respect week respectively for immunohistochemical determination of the expression of substance P (SP) in the posterior horn.MAIN OUTCOME MEASURES: The expression of substance P in the posterior horn at different times. Deeply-stained neurons in the 2nd week group. The mean positive neuron group varied within a certain range and were less than that of the 2nd week group. But they were all more than that of the controls[(5.08 ±0.41),(4.02±0.35), (2.58±0.33), (3.45±0.22) vs(0.85±0.23), t=6.85,5.90,3.49,6.85,P ＜0.05 or P ＜0.01].CONCLUSION: The expression of substance P increases when the cauda equina is compressed. Whether this is because the harmful stimuli increases SP expression and the latter in turn protects spinal cord by reducing the edema of spinal cord warrants more studies.
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Objective To investigate the correlation between surgical outcomes and body mass index (BMI) in patients with lumbar disc herniation. Methods 448 patients who underwent operative treatment for lumbar disc herniation were followed-up consecutively. The height and body weight of each patient was measured and recorded preoperatively. The BMI was calculated by the following formula, BMI=weight/height2 (kg/m2). The patients were asigned into three groups (normal group, BMI 28) based on the BMI. A questionnaire evaluation form was designed according to the 60 indexes put forward by North American Spine Association and the authors' clinical experiences. The post-operative signs and symptoms, living and working ability of the patients were evaluated by the questionnaire. Results Among the total 448 patients, none was lost for follow-up and all the patients were followed-up for average 2.48 (2.08-5.16) years. The improvement rate of the normal group was significantly higher than that of the obese group(P 0.05). The post-operative working ability of the patients in the normal group recovered more quickly than that of the patients in obese group (P 0.05). The remission rate, the post-operative pain and numbness between the male and the female were significantly different(P
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Objective: To investigate the proliferation and apoptosis of human osteosarcoma cell line U-2OS after sur-vivin gene was knocked down by siRNA synthesized in vitro. Methods: U-2OS cells were divided into 3 groups: Group A (blank control) , group B ( transfected with non-specific siRNA) and group C( transfected with survivin-specific siRNA). The morphological changes of U-2OS cells were observed with fluorescent microscope. The expression of survivin mRNA and protein were detected by reverse transcription polymerase chain reaction ( RT-PCR) and Western blotting. The anti-proliferative effects were assessed by MTT and the rate of apoptosis was examined by flow cytometry in 3 groups. The results of the 3 groups were analyzed and compared. Results: Survivin specific siRNA significantly down-regulated mRNA and protein expression of survivin. Expression of survivin protein in group C was significantly lower than those in group A and B( P