Objective To compare the biomechanical differences among the five internal fixation modes in treatment of Day type Ⅱ crescent fracture dislocation of pelvis (CFDP), and find an internal fixation mode which was the most consistent with mechanical principles. Methods Based on the pelvic CT data of a healthy adult male volunteer, a Day type Ⅱ CFDP finite element model was established by using Mimics 17.0, ANSYS 12.0-ICEM, Abaqus 2020, and SolidWorks 2012 softwares. After verifying the validity of the finite element model by comparing the anatomical parameters with the three-dimensional reconstruction model and the mechanical validity verification, the fracture and dislocated joint of models were fixed with S1 sacroiliac screw combined with 1 LC-Ⅱ screw (S1+LC-Ⅱ group), S1 sacroiliac screw combined with 2 LC-Ⅱ screws (S1+2LC-Ⅱ group), S1 sacroiliac screw combined with 2 posterior iliac screws (S1+2PIS group), S1 and S2 sacroiliac screws combined with 1 LC-Ⅱ screw (S1+S2+LC-Ⅱ group), S2-alar-iliac (S2AI) screw combined with 1 LC-Ⅱ screw (S2AI+LC-Ⅱ group), respectively. After each internal fixation model was loaded with a force of 600 N in the standing position, the maximum displacement of the crescent fracture fragments, the maximum stress of the internal fixation (the maximum stress of the screw at the ilium fracture and the maximum stress of the screw at the sacroiliac joint), sacroiliac joint displacement, and bone stress distribution around internal fixation were observed in 5 groups. Results The finite element model in this study has been verified to be effective. After loading 600 N stress, there was a certain displacement of the crescent fracture of pelvis in each internal fixation model, among which the S1+LC-Ⅱ group was the largest, the S1+2LC-Ⅱ group and the S1+2PIS group were the smallest. The maximum stress of the internal fixation mainly concentrated at the sacroiliac joint and the fracture line of crescent fracture. The maximum stress of the screw at the sacroiliac joint was the largest in the S1+LC-Ⅱ group and the smallest in the S2AI+LC-Ⅱ group. The maximum stress of the screw at the ilium fracture was the largest in the S1+2PIS group and the smallest in the S1+2LC-Ⅱ group. The displacement of the sacroiliac joint was the largest in the S1+LC-Ⅱ group and the smallest in the S1+S2+LC-Ⅱ group. In each internal fixation model, the maximum stress around the sacroiliac screws concentrated on the contact surface between the screw and the cortical bone, the maximum stress around the screws at the iliac bone concentrated on the cancellous bone of the fracture line, and the maximum stress around the S2AI screw concentrated on the cancellous bone on the iliac side. The maximum bone stress around the screws at the sacroiliac joint was the largest in the S1+LC-Ⅱ group and the smallest in the S2AI+LC-Ⅱ group. The maximum bone stress around the screws at the ilium was the largest in the S1+2PIS group and the smallest in the S1+LC-Ⅱ group. Conclusion For the treatment of Day type Ⅱ CFDP, it is recommended to choose S1 sacroiliac screw combined with 1 LC-Ⅱ screw for internal fixation, which can achieve a firm fixation effect without increasing the number of screws.
OBJECTIVE: To explore a method of reconstruction of hip joint function after deformed healing of the upper 1/3 of fractured femur as a complication of old fracture dislocation of hip joint. METHODS: A patient with loss of function in hip joint and fusion of knee joint was treated with lock for femur intra-medullary fixation in April 1997. RESULTS: Before operation, the diseased hip joint lost its most functions and the entire lower extremity was disabled because the knee joint had been fused. One year after operation, the follow-up examination revealed that the patient could walk by crutches without discomfort, his daily life and work recovered to normal. CONCLUSION: It is effective to treat a patient suffering old fracture-dislocation of hip joint complicated with deformed healing of the upper 1/3 of fractured femur by means of individualized artificial joint replacement and a prosthesis body with lock for femur intra-medullary fixation, and it is helpful for the development of a new clinical idea to reconstruct functions in the management of some particular cases.
Objective To compare the therapeutic effect of transforaminal lumbar interbody fusion (TLIF) and posterior lateral fusion (PLF) in treatment of thoracolumbar spine fracture and dislocation. Methods From January 2005 to July 2007, 35 patients (22 males, 13 females, aged 17-53 years old) with thoracolumbar spine fracture and dislocation (T11-L3) received posterior open reduction and pedicle nail-stick system internal fixation. Among which, 14 patients underwent TLIF(group TLIF), and the rest 21 patients underwent PLF (group PLF). According to AO classification, group TLIF had 3 cases of A3, 7 cases of B and 4 cases of C, while group PLF had 4 cases of A3, 10 cases of B and 7 cases of C. Based on American Spinal Injury Association (ASIA) Scoring Standard formulated in 2000, the motor score of group TLIF and group PLF was (50.6 ± 3.6) and (50.8 ± 4.2) points, respectively; and the sensory score was (170.5 ± 42.7) and (153.8 ± 23.7) points, respectively. No significant difference was noted between 2 groups in general information (P gt; 0.05). Results The operation time of group TLIF and group PLF was (316 ± 32) minutes and (254 ± 27) minutes, and the blood loss of group TLIF and group PLF was (487 ± 184) mL and (373 ± 72) mL, indicating there were significant differences between 2 groups (P lt; 0.05). Wounds of all patients were healed by first intention and there was no death, aggravation of neurological function impairment and compl ication of internal fixation instrument loosening and breaking. All 35 cases were followed up for 9-23 months with an average of 14.6 months. Postoperatively, the thoracolumbar bone fusion rate of group TLIF and group PLF was 100% and 85.7%, respectively, indicating there was a significant difference (P lt; 0.05). At 3 months after operation, the motor score of group TLIF and group PLF was increased by (10.4 ± 10.0) and (9.4 ± 9.3) points, respectively; and the sensory score was upgraded by (26.5 ± 22.8) and (28.8 ± 28.4) points, respectively, showing there were no significant difference (P gt; 0.05). At immediate moment, 3, 6 and 12 months after operation, the spine height restoration of group TLIF was (5.4 ± 2.1), (5.4 ± 1.9), (5.4 ± 1.4) and (5.3 ± 1.3) mm, respectively; while it was (5.3 ± 2.6), (5.3 ± 2.2), (4.8 ± 3.1) and (4.2 ± 3.6) mm for group PLF. Meanwhile, the Cobbangle recovery of group TLIF was (14.5 ± 3.5), (14.5 ± 3.6), (14.4 ± 3.4) and (14.4 ± 3.6)º, respectively; while it was (14.3 ± 2.7), (14.2 ± 3.1), (12.2 ± 2.8) and (11.7 ± 3.3)º for group PLF. Concerning the spine height restoration and the Cobb angle recovery, no significant difference was observed between 2 groups at immediate moment and 3 months after operation (P gt; 0.05), but significant differences were noted at 6 and 12 months after operation (P lt; 0.05). Conclusion For the treatment othoracolumbar spine fracture and dislocation, TLIF is superior to PLF in bony fusion and restoration of spine column height.
Objective To explore the effectiveness of Colorado 2TM system in the stabil ity reconstruction of sacroil iac joint fracture and dislocation in Tile C pelvic fracture. Methods Between February 2009 and January 2011，8 cases of Tile C pelvic fracture were treated with Colorado 2TM system. There were 3 males and 5 females with an average age of 34.4years (range，22-52 years). Fractures were caused by traffic accident in 3 cases, by fall ing from height in 3 cases，and by crash of heavy object in 2 cases. According to Tile classification, 5 cases were classified as C1-2, 2 cases as C1-3，and 1 case as C2. The time between injury and operation was 5-10 days (mean, 7 days). After skeletal traction reduction, Colorado 2TM system was used to fix sacroil iac joint, and reconstruction plate or external fixation was selectively adopted. Results The postoperative X-ray films showed that the reduction of vertical and rotatory dislocation was satisfactory, posterior pelvic ring achieved effective stabil ity. All the incisions healed by first intention, and no blood vessel or nerve injury occurred. Eight patients were followed up 6-24 months (mean, 12 months). No loosening or breakage of internal fixation was observed and no re-dislocation of sacroil iac joint occurred. The bone heal ing time was 6-12 months (mean, 9 months). According to Majeed’s functional criterion, the results were excellent in 5 cases, good in 2 cases, and fair in 1 case at last follow-up. Conclusion Colorado 2TM system could provide immediate stabil ity of pelvic posterior ring and good maintenance of reduction effect, which is an effective method in the therapy of sacroil iac joint fracture and dislocation in Tile C pelvic fracture.
Objective To evaluate the deviation between actual and simulated screw placement after cervical pedicle screw placement assisted by 3D printed navigation template, and analyze the correlation between screw placement deviation and navigation pipe length. Methods A total of 40 patients undergoing cervical 1-7 pedicle screw insertion assisted by 3D printed navigation template in Zigong Fourth People’s Hospital between February 2018 and August 2020 were included in this prospective study. These patients were divided into 3 groups randomly, including 12 patients with a 5-mm pipe length (5 mm group), 13 patients with a 10-mm pipe length (10 mm group), and 15 patients with a 15-mm pipe length (15 mm group). Three-dimensional modeling was performed on preoperative cervical CT images of these patients and simulated pedicle screw was placed. Individualized pedicle screw navigation templates were designed according to the position and direction of simulated pedicle screws, and 3D printing was performed on the cervical model and navigation templates. Preoperative 3D printed model and navigation templates were used to simulate the surgical process to confirm the safety of screws. During the operation, pedicle screw placement was performed according to the preoperative design and simulated surgical process. The postoperative CT images were registered with the preoperative CT images in 3D model. The safety of screw placement was evaluated by the postoperative screw placement Grade, and the accuracy of screw placement was evaluated by measuring the deviation of screw placement point and the deviation of screw placement direction in horizontal plane (inclination angle) and sagittal plane (head inclination angle). The influence of different navigation pipe lengths on the safety and accuracy of screw placement was analyzed. Results A total of 164 pedicle screws were inserted with navigation template assistance, including 48 screws (38 in Grade 0 and 10 in Grade 1) in the 5 mm group, 52 screws in the 10 mm group (all in Grade 0), and 64 screws (52 in Grade 0 and 12 in Grade 1) in the 15 mm group, and the difference in the grade among the three groups was statistically significant (P<0.05). When the navigation pipe length was 5, 10, and 15 mm, respectively, the screw entry point deviation was (1.87±0.63), (1.44±0.63), and (1.66±0.54) mm, respectively, the inclination angle deviation was (2.72±0.25), (0.90±0.21), and (1.84±0.35)°, respectively, and the head inclination angle deviation was (8.63±1.83), (7.15±1.38), and (8.24±1.52)°, respectively. The deviations in the 10 mm group were all significantly less than those in the other two groups (P<0.05). Conclusions In the cervical pedicle screw placement assisted by navigation template, all the screws were Grade 0 or Grade 1, with high safety. The mean deviation of the screw entry point is within 2 mm, with high accuracy. When the length of navigation pipe is 10 mm, the safety and accuracy of screw placement can be fully guaranteed.
ObjectiveTo report a new type of anatomical locking plate for sternocalvicular joint, and investigate its effectiveness in treatment of sternoclavicular joint fracture and dislocation.MethodsA new type of anatomical locking plate for sternoclavicular joint was developed, which accorded with the anatomical features and biomechanical characteristics of Chinese sternoclavicular joint. By adopting the method of clinical randomized controlled study, 32 patients with the sternoclavicular joint fracture and dislocation who met the selection criteria between June 2008 and May 2015 were randomly divided into groups A and B (n=16), and the patients were treated with new anatomic locking plate and distal radial T locking plate internal fixation, respectively. There was no significant difference between 2 groups in gender, age, injured side, body mass index, cause of injury, type of injury, the time from injury to operation, and preoperative Rockwood grading score (P>0.05). The operation time, intraoperative blood loss, incision length, hospitalization time, and postoperative complications in 2 groups were recorded, and the effectiveness was evaluated by Rockwood grading score.ResultsThe operations of 2 groups completed successfully. The operation time, intraoperative blood loss, and hospitalization time in group A were significantly less than those in group B (P<0.05), but there was no significant difference in the incision length between 2 groups (t=0.672, P=0.507). All the patients were followed up 18-30 months (mean, 24 months). In group A, there were 1 case of sternoclavicular joint pain and 2 cases of wound infection; in group B, there were 1 case of sternoclavicular joint pain, 1 case of internal fixation loosening, and 1 case of sternoclavicular joint re-dislocation; there was no significant difference in complication incidence between 2 groups (P=1.000). The Rockwood grading scores at each time point after operation in 2 groups were significantly higher than those before operation. At 1 month after operation, the Rockwood grading score in group A was significantly higher than that in group B (t=2.270, P=0.031); but there was no significant difference in the Rockwood grading scores between the 2 groups at 6 months and at last follow-up (P>0.05). At last follow-up, according to the Rockwood scoring standard, the results of group A were excellent in 13 cases, good in 2 cases, poor in 1 case, the excellent and good rate was 93.75%; the results of group B were excellent in 11 cases, good in 4 cases, poor in 1 case, and the excellent and good rate was 93.75%; there was no significant difference between 2 groups (Z=–0.748, P=0.455).ConclusionThe new type of anatomic locking plate accords with the Chinese anatomical characteristics. It has the advantages of easy operative procedure, less surgical trauma, shorter operation time, less intraoperative blood loss, shorter hospitalization time, and it can achieve better results in the treatment of sternoclavicular joint fracture and dislocation.