Displacement Of Internal Fixation Research Articles

Finite element analysis of proximal femur bionic nail for treating intertrochanteric fractures in osteoporotic bone

This study compared the biomechanical characteristics of proximal femur bionic nail (PFBN) and proximal femoral nail antirotation (PFNA) in treating osteoporotic femoral intertrochanteric fractures using finite element analysis. Under similar bone density, the PFBN outperforms the PFNA in maximum femoral displacement, internal fixation displacement, stress distribution in the femoral head and internal fixation components, and femoral neck varus angle. As the bone density decreases, the PFBN’s biomechanical advantages over PFNA become more pronounced. This finding suggests that the PFBN is superior for treating osteoporotic intertrochanteric femoral fractures.

Wright's Technique with the Addition of Visualized Axial Cortical Windows in Odontoid Fractures.

This study sought to investigate and evaluate a modified axial translaminar screw fixation for treating odontoid fractures. We performed a retrospective study at Wenzhou Medical University Affiliated Second Hospital between March 2016 and June 2018. We retrospectively collected and analyzed the medical records of 23 cases with odontoid fractures. All patients were identified as type II odontoid fractures without neurological deficiency and serious diseases following the classification of Anderson. The average age, gender ratio, and body mass index (BMI) were 54.3 ± 11.1 years, 12 men to 11 women, and 22.6 ± 2.4 kg/m2, respectively. Patients in this study accepted screw fixation using our modified axial translaminar screw fixation combined with atlas pedicle or lateral mass screw fixation. Within the technique, a small cortical “window” was dug in the middle of the axial contralateral lamina, such that the screws in the lamina were visualized to prevent incorrectly implanting the posterior spinal canal through the visualized “window.” A total of 46 bone screws were accurately inserted into the axial lamina without using fluoroscopy. The length of all translaminar screws ranged between 26 and 30 mm, while the diameter was 3.5 mm. During the follow‐up survey, the visual analog scale (VAS) and neck disability index (NDI) were measured. We provide a simple modification of Wright's elegant technique with the addition of “visualized windows” at the middle of the axial lamina. In all patients, screws were inserted accurately without bony breach and the screw angle was 56.1 ± 3.0°. Mean operative time was 102 ± 28 min with an average blood loss of 50 ± 25 mL. Postoperative hemoglobin and mean length of hospital stay were 12.0 ± 1.4 g/dL and 10.4 ± 3.4 days, respectively. The average follow‐up time of all cases was 14.7 months and no internal fixation displacement, loosening, or breakage was found. All patients with odontoid fractures reported being satisfied with the treatment during the recheck period and good clinical outcomes were observed. At 1, 6, and 12 months, NDI and VAS showed that the symptoms of neck pain and limitations of functional disability improved significantly during follow‐up. Our results suggest that the modified translaminar screw fixation technique can efficiently treat Anderson type II odontoid fracture, followed by the benefits of less soft tissue dissection, simple operation, no fluoroscopy, and accurate placement of screws.

How to choose the suitable FNS specification in young patients with femoral neck fracture: A finite element analysis

BackgroundConsensus regarding the optimal approach for the treatment of femoral neck fractures remains lacking. A new internal fixation femoral neck system (FNS) was developed and used in clinical practice. We aimed to investigate the biomechanical outcomes of different types of FNS in the treatment of unstable femoral neck fractures. MethodIn this study, we constructed three different types of unstable femoral neck fractures of Pauwels classification with angles of 50°, 60°, and 70°. We set up four test groups, namely, the one-hole plated FNS group, two-hole plated FNS group, inverted cannulated screw group and triangle cannulated screw group. Under 2100 N axial loads, displacements and the von Mises stress of the femur and internal fixation components were measured for each fracture group. ResultsWhen the Pauwels angle was 50°or 60°, the one-hole locking plated FNS was as superior as the two-hole plated FNS in terms of femur and internal fixation displacement, and the inverted cannulated screw had slightly better stability than the triangular cannulated screw. However, when the angle increases to 70°, the two-hole locking plate has the minimum displacement, followed by the triangular cannulated screw and inverted cannulated screw, which is the worst displacement for the single-hole locking plate. Regardless of the angle, the two sets of FNS have higher internal fixation stress than the two sets of cannulated screws, which is approximately 1.6-3.0 times that of the cannulated screw group. ConclusionFrom the perspective of biomechanics, we suggest that when the angle of the fracture line is less than 60°, both single-hole locking plated or double-hole locking plated FNS can be used to treat unstable femoral neck fractures. However, when the angle of the fracture line is greater than 70°, we recommend using a double-hole locking plated FNS. This result needs further verification in further clinical studies.

Study on the safety and clinical efficacy of osteotomy after halo pelvic traction in severe scoliosis accompanied with split cord malformation

Objective: To investigate the safety and clinical efficacy of osteotomy after halo pelvic traction in severe scoliosis accompanied with split cord malformation. Methods: The clinical data of 14 patients with severe scoliosis accompanied with split cord malformation admitted to the Department of Spinal Surgery, Guizhou Orthopedic Hospital from August 2015 to August 2019 were retrospectively analyzed.There were 6 males and 8 females, aged (19.8±5.0) years (range:13 to 34 years). All patients received spinal orthopedic surgery after halo pelvic traction for 3 to 7 weeks.The data of traction time, height, Cobb angle in the main curved coronal plane and sagittal plane, lung function and nutritional status of the patient were collected before and after the treatment. Paired t test was used to compare the evaluation indexes. Results: The traction time of the 14 patients was (35.2±8.3)days (range:20 to 49 days), and the height of them increased from (156.7±7.6)cm (range:141 to 166 cm) before traction to (167.0±6.4)cm (range:154 to 177 cm) after traction（t=-10.49，P<0.01）. The Cobb angle on the main curved coronal plane decreased from (117.4±17.2) ° (range: 91°to 176°) before traction to (56.4±8.1) ° (range:44°to 68°) after traction（t=13.90，P<0.01）. The sagittal Cobb angle decreased from (92.5±11.6) ° (range:62°to 132°) before traction to (41.7±7.7) °(range:29°to 51°) after traction（t=12.11，P<0.01）. No complications such as loosening of nailing and infection occurred during traction, and no decrease of nerve function occurred. Nine patients underwent single segment acromial transpedicle osteotomy and five underwent double segment adjacent asymmetric shortening osteotomy. None of the patients underwent longitudinal fracture resection. The lung function and nutritional status were improved after traction and surgery(all P<0.01). Postoperative follow-up was (22.5±9.1)months (range:12 to 36 months). At the last follow-up, the coronal Cobb angle was (56.3±7.1) °, and the sagittal Cobb angle was (37.7±6.5) °, showing no statistically significant difference from the angle after traction(t=0.16,P=0.88; t=2.28,P=0.32). There was no loss of orthopedic angle. None of the patients had internal fixation displacement, loosening or fracture. Conclusion: The treatment of severe scoliosis with accompanied with split cord malformation by halo pelvic traction is safe and effective, which is worthy of further confirmation by large sample study.

Bridging system for severe comminuted femoral fracture

To explore the clinical effect of bridging system in the treatment of severe comminuted femoral fracture. From March 2016 to October 2018, 50 patients with severe comminuted femoral fracture including 35 males and 15 females, aged 48 to 72(54.6±8.7) years, were admitted. All cases were comminuted fractures of the femoral shaft, 16 with proximal femur fractures and 7 with distal femur fractures. All cases were all unilateral fractures, 23 on the left and 27 on the right. The time from injury to operation was 5 to 60 (26.7±13.3) hours. The cause of injury was traffic accident, 12 cases with high fall, 35 cases fell and 3 cases fell accidentally. The patients were treated with bridge combined internal fixation system, and the operative effect and fracture healing were analyzed. The operation was successful in all patients. There was no change to other fixed operation. The operation time was (75.8±12.3) min, the amount of bleeding was(356.4±64.8) ml, and there was no serious postoperative complications such as infection, internal fixation displacement, re fracture and nonunion. After 6 to 36 months follow-up, the fracture healing was evaluated by Warden's score. With the extension of observation time, Warden's score gradually increased, and the time of bone healing was(5.5±0.9) months. Harris score and HSS score were used to evaluate the function of hip and knee joint respectively. With the extension of time, Harris score and HSS score increased gradually. Six months after operation, Harris score was 83.5±11.2, HSS score was 79.7±10.5. During the follow-up period, there were no serious complications such as internal fixation displacement, re-fracture, nonunion of fracture and deep vein thrombosis of lower extremity. The bridge combined internalfixation system has better safety and effectiveness in the treatment of severe comminuted femoral fracture. As long as the requirements of local anatomy and biomechanics are strictly mastered and the operation risks are fully evaluated in combination with imaging, the better fixation effect can be achieved. The operation has less trauma, fewer complications and simple operation, which is believed to have a wider application potential. Due to the limited sample size and follow-up time, no clinical control was set up, the results of the study still need to be further verified by prospective trials.

Treatment of Denis type B thoracolumbar burst fractures by anterior single segmental decompression and instrumentation through Endoring self-support retractor-assisted minimally invasive small incision approach

Objective To evaluate the clinical efficacy of anterior single segmental decompression and instrumentation through Endoring self-support retractor-assisted minimally invasive small incision approach in the treatment of Denis type B thoracolumbar burst fractures. Methods A retrospective case series study was made on 26 cases (14 males and 12 females, mean age of 48.5 years) of Denis type B thoracolumbar burst fractures treated by anterior single segmental decompression and instrumentation through Endoring self-support retractor-assisted minimally invasive small incision approach from January 2007 to June 2009. Age was 18-68 years (mean, 48.5 years). The fractured vertebrae included T1 in three cases, L1 in 18 and L2 in five. The neurological status was Grade C in eight cases, Grade D in 12 cases and Grade E in six cases according to American Spinal Injury Association (ASIA) classification. The operation duration, blood loss and incision length were recorded. The neurological function, lower back pain were evaluated by visual analogue score (VAS), correction of kyphosis and restoration of the fractured vertebral body height followed and documented at 3, 6 and 9 months and annually after surgery. The healing of the graft was assessed using Brantigan method based on 3-dimensional computed tomography at final follow-up. Results All patients were successfully managed with this approach. The operation duration was (214.6±30.5)min, and the intraoperative blood loss was (389.7±57.1)ml. The length of incision was (8.5±1.3)cm. All patients were followed up for (6.3±0.4)years. At final follow-up, the neurological functions of all patients with incomplete neurological deficit were improved for at least one grade. The VAS of lower back pain was improved from preoperative (7.8±1.6)points to (2.1±0.8)points at final follow-up (P<0.05). The height of the intervertebral body was restored from preoperative (29.8±5.3)mm to(35.2±2.4)mm at final follow-up (P<0.05). The kyphosis was corrected from preoperative (20.4±11.7)° to (11.3±5.5)° at final follow-up (P<0.05). Bone fusion was achieved in all patients, with no looseness, breakage or displacement of internal fixation at follow-up. Conclusions Anterior single segmental decompression and instrumentation through Endoring self-support retractor-assisted minimally invasive small incision approach can reduce the surgical trauma, achieve complete spinal canal decompression, adjust kyphosis, fix segment, obtain high rate of bone graft fusion and hence is a safe and effective method with minimal invasion for Denis type B thoracolumbar burst fractures. Key words: Spinal fractures; Thoracic vertebrae; Lumbar vertebrae; Fracture fixation, internal

Anterior cervical hybrid surgical treatment for multilevel cervical spondylotic myelopathy

To evaluate the clinical results of anterior cervical discectomy and reconstruction with a self-locking cage and internal fixation with short segmental plate for multilevel cervical spondylotic myelopathy. From January 2012 to June 2015, a total of 106 patients received anterior cervical discectomy and reconstruction with a self-locking cage and internal fixation with short segmental plate were followed up. There were 71 males and 35 females, aged from 42 to 74 years old with an average of(55.4±5.1) years. Three segments were involved in 82 cases and four segments in 24 cases. Operation time, blood loss, postoperative drainage, and hospitalization time were recorded. Visual analogue scale(VAS) and Japanese Orthopaedic Association Score (JOA) were analyzed before and after operation(including 5 days, 3, 6, 12 months after operation and final follow-up), and the JOA improvement rate was analyzed. The cervical lordosis and ROM were measured before and after operation(including the follow-up point above) by X-rays. The postoperative complications were recorded and analyzed as well. All the operations were successful. The average operative time was (126.2±25.1) min, and the amount of blood loss was (82.1±26.3) ml. All the patients were followed up from 12 to 48 months with an average of (30.4±10.5) months. The VAS score of neck pain and JOA score was significantly better from 6.11±1.54 and 9.22±2.42 preoperatively to 2.14±0.51 and 12.46±1.42 at 5 days post-operation, respectively(P<0.05). The improvement rate of JOA was (56.7±21.6)%, there was no statistically significant difference of VAS, JOA scores and the improvement rate of JOA at each time after operation (P>0.05). Postoperative cervical lordosis at 3 months was significantly improved from preoperative (11.5±6.8)° to (19.6±8.9)°(P<0.05), and it can keep satisfactory stability until final follow-up(P>0.05). Postoperative ROM at 3 months was significantly decreased from the preoperative (37.6±10.4)° to (18.2±5.9)°(P<0.05), but there was no significant change in the process of follow-up (P>0.05). All the complications such as dysphagia (19 cases), axial neck pain(6 cases), cerebral fluid leakage(3 cases), and hoarseness(2 cases), got better after conservative treatment. Three cases had intervertebral space non-fusion until final follow-up(without clinical symptom), but no loosening, breakage, or displacement of internal fixation were found. Anterior cervical discectomy, reconstruction with a self-locking cage and internal fixation with short segmental plate which can reduce intraoperative injury, restore cervical lordosis, improve neurological function and lower postoperative complications, it is an alternative treatment for multilevel cervical spondylotic myelopathy.

Treatment of displaced femoral neck fracture in young adults with close reduction and femoral neck locking plate fixation

To investigate the clinical effects of close reduction and proximal femoral locking plate fixation for the treatment of femoral neck fractures in young adults. From August 2010 to 2014 August, 54 patients with displaced femoral neck fracture were treated with closed reduction and proximal cannulated screw locking plate fixation. There were 34 males and 20 females, aged from 18 to 55 years with an average of 39.8 years. The informations of fracture healing and complications were recorded after operation. According to Harris criteria, the function of hip joint was evaluated. All patients were followed up from 4 to 24 months with an average of 11.3 months. Three cases occurred fracture nonunion, fracture union rate was 94.4%(51/54), union time was from 3 to 6 months with an average of 4.1 months. Among the healed 51 cases, the median of femoral neck shorten was 0.8 mm with the mean of (0.48±0.46) mm. No complications such as infection, internal fixation displacement were found during follow up. According to Harris criteria, 40 cases obtained excellent results, 9 good, 2 fair, 3 poor. Close reduction and proximal femoral locking plate fixation is an effective method in treating femoral neck fracture in young adults, it has advantages of avoiding the femoral neck crispation, reliable fixation, high rate of fracture union and good functional recovery.