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Objective To investigate the effect of medial collateral ligament (MCL) repair and coronoid process fracture fixation on stability of the Terrible Triad of the elbow. Methods CT and MRI scan images of elbow joints from one healthy 28-year-old male volunteer were used to establish three elbow models. Model A: normal model. Model B: repair of coronoid process fractures, without MCL repair. Model C: repair of MCL, without repair of ulnar coronoid processes. Longitudinal loads were applied on the three models to analyze the displacement and stress distributions of the elbow joint under different working conditions and compare the stability of the elbow joint. Results The displacement and stress distributions of the three models were similar. The maximum displacement and maximum stress of the articular surface were located at the ulna pulley notch, while the minimum displacement was located at the coronoid process and its medial side. The minimum stress was located at the lower lateral side of the coronoid process. There were no statistical differences in the maximum displacement and stress among the three models (P>0.05). Conclusions When the lateral column is stable, the effect of repairing the MCL and fixing the fracture block of ulnar coronoid process is similar.
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BACKGROUND:Repair programs of posterolateral tibial plateau fracture included posterior plate screws, lateral plate screw and anterior and posterior lag screw fixation. To choose which fixation methods depends on clinical experiences of physicians. Study results are mainly clinical reports, and lack of mechanical evidence. OBJECTIVE:To compare biomechanical changes in three fixed manners (lateral plate screw group, posterior plate screw group and anterior and posterior lag screw group) in the repair of posterolateral fracture of tibial plateau from the angle of biomechanics. METHODS:A total of tibial specimens of six adult male antisepsis corpses (12 samples) were used for measuring bone mineral density of metaphysis. 1/2 posterolateral tibial plateau fracture model was established by electric pendulum saw. The model was randomly divided into three groups:lateral plate screw group, posterior plate screw group and anterior and posterior lag screw group. Finite element method and biomechanics were used to test axial displacement value and the maximal displacement distribution area under the axial loads of 250, 500, and 1 000 N. RESULTS AND CONCLUSION:There was no significant difference in average bone density in three groups of metaphysis (P>0.05). The minimum axial displacement of the fracture fragments was in the anterior and posterior lag screw group (0.013 521 mm), fol owed by posterior plate screw group (0.016 991 mm), and the maximum was visible in the lateral plate screw group (0.138 200 mm) under 250 N load. Displacement value was similar to the 250 N under 500 and 1 000 N. According to the results of biomechanics, displacement values of anterior and posterior lag screw was obviously less than the lateral plate screw group and posterior plate screw group (P0.05). The maximal displacement distribution area was proximal tibiofibular joint border zone in two methods. These data indicated that the biomechanical stability was most advantageous in the anterior and posterior lag screw group, and poorest in the lateral plate screw group. In the clinic, anterior and posterior lag screw fixation can be used as a first choice for repair of posterolateral tibial plateau fracture.
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BACKGROUND:Studies on tibial plateau fractures had gradualy focused on “360° stereochemical structure” from medial and lateral “double track structure” nowadays. Scholars pay great attention on the stability and reposition of posterior plateau and functional recovery after reduction. The choice of fixation material of posterior plateau was controversial. OBJECTIVE:To discuss the biomechanical characteristics of posterolateral fracture of tibial plateau using three types of internal fixation. METHODS:Using three-dimensional finite element analysis, we simulated 1/2 and 1/4 posterolateral tibial plateau fractures. Three types of internal fixation were used: two anterior 6.5 mm lag screws, lateral 4.5 mm L-shape plate, and posterior 3.5 mm T-shape plate. 500 N was loaded at the center of the tibial plateau verticaly, and biomechanical status of three types of fixation was compared. RESULTS AND CONCLUSION: In 1/2 fracture model, anterior lag screw group and posterior plate group gained least displacement in al directions, as lateral plate group gained more. In 1/4 model, the advantage in displacement of anterior lag screw group was more apparent, the second was posterior plate group, and the last was lateral plate group. In 1/2 fracture model, the maximum stress of anterior lag screw was 36.523 MPa, which of lateral plate group was 153.372 MPa and posterior plate group was 115.922 MPa. The maximum stress left in the separate bone of lag screw group was 4.309 MPa, which of lateral plate group was 4.37 MPa and posterior plate group was 3.124 MPa. In 1/4 fracture model, the maximum stress of anterior lag screw was 36.803 MPa, which of lateral plate group was 153.336 MPa and posterior plate group was 104.234 MPa. The maximum stress left in the separate bone of lag screw group was 1.195 MPa, which of lateral plate group was 0.827 MPa and posterior plate group was 1.196 MPa. Results indicated that anterior lag screw could bear more stress and gained least displacement after loading, and the fixation was more stable. Posterior plate can give more stabilization when the separate bone was bigger (1/2), similar to anterior lag screw. When the separate bone was smaler (1/4), posterior plate model was less stable than anterior lag screw. Lateral plate model, with poor stabilization, was the worst choice in three types of fixation.
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BACKGROUND:Patients with elder hip fracture has more complications, poor affordability and high perioperative risk, so the preoperative ful preparation and evaluation are needed. OBJECTIVE:To predict the accuracy of the prognosis of elderly patients with hip fracture through comparing the difference between American Society of Anesthesiologists score and Daping orthopedics operation risk scoring system for senile patients. METHODS:A retrospective study was performed on 300 cases with elderly hip fracture selected from January 2011 to December 2012 from Department of Orthopedics, Gongli Hospital of Pudong. American Society of Anesthesiology score and Daping orthopedics operation risk scoring system for senile patients were conducted before treatment, and the predictive values of two scoring systems on the incidence of complications and mortality were compared. RESULTS AND CONCLUSION:According to the American Society of Anesthesiology score and Daping orthopedics operation risk scoring system for senile patients, 148 cases and 97 cases had complications respectively. On the contrary, the actual number of complications was 89. The former predicted value was significantly higher than the actual value, and there was no significant difference between the latter forecast value and the actual value. The numbers of death predicted by American Society of Anesthesiology score and Daping orthopedics operation risk scoring system for senile patients were 27 cases and six cases, but the actual number of death was three cases, indicating that former predicted value was significantly higher than the actual value, and there was no significant difference between the latter predicted value and the actual value. The American Society of Anesthesiology score has a certain errors in predicting the postoperative complications and mortality of patients with elderly hip fractures, but it is simple and useful in clinic. The Daping orthopedics operation risk scoring system for senile patients can accurately evaluate elderly hip fracture operation risk, and can predict the postoperative complications and mortality more objective when compared with the American Society of Anesthesiology score.
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Objective To compare the clinical results of minimally invasive percutancous plate os-teosynthesis (MIPPO) and open reduction with internal fixation (ORIF) for treatment of distal tibial fractures. Methods From October 2006 to June 2007, 94 cases of closed distal tibial fracture with intact articular surface were treated by internal fixation with plates. Of them, 42 were treated with ORIF and 52 with MIPPO. We retrospectively analyzed their union time, malunion and complications. Results The average follow-up was 14.5 (8 to 24) months. In the ORIF group, 35 cases got union, 3 cases delayed union and 4 cases nonunion. The average time for union was 3.83 (3 to 8) months. There were no cases of malunion and 2 cases of superficial infection in this group. In the MIPPO group, 47 cases obtained union, 5 cases delayed union and none nonunion. The average time for union was 3.66(2 to 8) months. No significant differences were found between the 2 groups in total union time or in the union time for Type AI, Type A2 and Type B fractures respectively. The union time for Type A3 fracture was longer in the MIPPO group than in the ORIF group, but the union time for Type C fracture in the MIPPO group was shorter than in the ORIF group. In the MIPPO group, external rotation occurred in 2 cases and posterior angnlation displacement in 3, and 8 cases com-plained of discomfort around the ankle which was relieved after removal of the plate. Conclusions Gen-erally speaking, there is no significant difference between ORIF and MIPPO in union time for distal tibial fractures. ORIF may be superior to MIPPO in treatment of Type A3 fracture, but inferior to MIPPO in treatment of Type C fracture. A high rate of delayed union may be expected in patients who have been treated with MIPPO and have had anteroposterior angnlation.