Treatment of nonunion after femoral neck fracture with valgus intertrochanteric osteotomy: a case report with 18-year follow-up

We herein report the long-term effect of valgus intertrochanteric osteotomy for nonunion after femoral neck fracture. In this report, we describe our experience using valgus intertrochanteric osteotomy to treat nonunion after femoral neck fracture in a 20-year-old woman. The patient was discharged from the hospital 10 days after the operation, the internal fixation device was removed 1 year after the operation, and the patient was then followed up for 18 years. Valgus intertrochanteric osteotomy can effectively treat nonunion after adductive femoral neck fracture.

Primary Total Hip Arthroplasty versus Open Reduction and Internal Fixation in Displaced Fracture of Femoral Neck in Adults

Background: Femoral neck fracture as a prevalent skeletal injury accounts for 7% of orthopedic hospital admission. The aim of the present study is to evaluate the functional outcome of patients with femoral neck fracture treated with total hip arthroplasty (THA) and compare them with those undergoing fixation treatment. Methods: In this study, we reviewed patients in the age range of 45-60 years old with femoral neck fracture during 2007-2017. The subjects were assigned to either THA or fixation group. The primary outcome was hip function, evaluated with the Harris Hip Scale (HHS). Secondary outcomes included pain, local infection, avascular necrosis (AVN), thromboembolic event, loosening of the prosthetic and internal fixation device, prosthetic dislocation, non-union, and delayed-union. Results: In this study, 34 patients with displaced fracture of femoral neck were treated with acute THA and 38 patients were treated with fixation. The HHS was higher in the THA group compared to the fixation group (P < 0.050). The results of the present study indicated no significant difference in early postoperative complications over the first month between the two groups, but frequency of complications such as non-union, AVN, pain and loosening of the internal fixation device in the fixation group were significantly higher than the THA group after six months (P < 0.050). Conclusion: Over a period of six months, THA provided better hip function and significantly fewer postoperative complications compared to fixation.

Predicting the Failure Risk of Internal Fixation Devices in Chinese Patients Undergoing Spinal Internal Fixation Surgery: Development and Assessment of a New Predictive Nomogram

The current study is aimed at developing and validating a nomogram of the risk of failure of internal fixation devices in Chinese patients undergoing spinal internal fixation. We collected data from a total of 1139 patients admitted for spinal internal fixation surgery at the First Affiliated Hospital of Guangxi Medical University from May 2012 to February 2019. Of these, 1050 patients were included in the spinal internal fixation group and 89 patients in the spinal internal fixation device failure group. Patients were divided into training and validation tests. The risk assessment of the failure of the spinal internal fixation device used 14 characteristics. In the training test, the feature selection of the failure model of the spinal internal fixation device was optimized using the least absolute shrinkage and selection operator (LASSO) regression model. Based on the characteristics selected in the LASSO regression model, multivariate logistic regression analysis was used for constructing the model. Identification, calibration, and clinical usefulness of predictive models were assessed using C-index, calibration curve, and decision curve analysis. A validation test was used to validate the constructed model. In the training test, the risk prediction nomogram included gender, age, presence or absence of scoliosis, and unilateral or bilateral fixation. The model demonstrated moderate predictive power with a C-index of 0.722 (95% confidence interval: 0.644–0.800) and the area under the curve (AUC) of 0.722. Decision curve analysis depicted that the failure risk nomogram was clinically useful when the probability threshold for internal fixation device failure was 3%. The C-index of the validation test was 0.761. This novel nomogram of failure risk for spinal instrumentation includes gender, age, presence or absence of scoliosis, and unilateral or bilateral fixation. It can be used for evaluating the risk of instrumentation failure in patients undergoing spinal instrumentation surgery.

Evaluation of S2 alar and traditional S1 pedicle fixation for severe lumbar spondylolisthesis in different bone mineral densities: a finite element analysis

Purpose: Little is known about the biomechanical performance of L5-S2 alar internal fixation constructs after posterior lumbar interbody fusion. This study aimed to compare the biomechanical effect of L5-S1 internal fixation and L5-S2 alar internal fixation on severe lumbar spondylolisthesis. Methods: A normal male volunteer without a history of spinal disease was selected, lumbar CT data was collected. An intact L5-S2 three-dimensional finite element model was created by Mimics and Geomagic.Two kinds of fixation methods were reconstructed including (1) the L5-S1 screw fixation model and (2) the L5-S2 alar fixation model. The inverse repair was performed using Geomagic software, the internal fixation device was drawn using Creo software, and the model parameters were set and analyzed using ANSYS Workbench software. Results: The validity of the intact model shows that the ROM of the model is similar to that of a reported cadaveric study. The average stress of the L5-S2 alar internal fixation device was 86.9-111% higher(P＜0.001) than that of the L5-S1 fixation device when the bone of the S1 screw path reached the yield threshold. The maximal stress of the S1 screw in the L5-S2 alar fixation was significantly lower (P＜0.001) than it in the L5-S1 fixation when the stress exceeds the S1 bone yield threshold. When the S1 screw path bone yielded, the maximal deformation value of the S1 screw path was similar in both models (P>0.05), while the average deformation value of the S1 screw path in L5-S2 alar fixation was significantly higher (P＜0.01) than it in L5-S1 fixation. Conclusion: Extending fixation to the S2 wing can significantly improve internal fixation device stability and reduce the risk of intraoperative and postoperative fractures while avoiding injury to the sacroiliac joint, reducing the difficulty of surgery and the risk of injury to surrounding tissues. It is a reasonable plan for the treatment of moderate and severe lumbar spondylolisthesis with osteoporosis.

Evaluation of S2 Alar and Traditional S1 Pedicle Fixation for Severe Lumbar Spondylolisthesis in Different Bone Mineral Densities: A Finite Element Analysis

Background: Lumbar spondylolisthesis is a common disease in older populations. The surgical treatment of spondylolisthesis has a history of more than 50 years, with L5-S1 screws widely used in clinical practice to reduce slippage and fusion. However, some patients with severe lumbar spondylolisthesis and osteoporosis could have complications, such as internal fixation rupture, S1 screw loosening, and incomplete slippage reduction. To better treat this kind of patient, sacral screw fixation is gradually becoming more common. Little is known about the biomechanical performance of L5-S2 alar internal fixation constructs after posterior lumbar interbody fusion. This study aimed to compare L5-S1 reduction and fixation methods and explore whether extending the fixation to include the S2 alar can significantly improve the stability of the internal fixation device. METHODS: Two kinds of validated finite element models of the L5-S1 segment were reconstructed via computed tomography images, including (1) the L5-S1 screw fixation model and (2) the L5-S2 alar fixation model. The inverse repair was performed using Geomagic software, the internal fixation device was drawn using Creo software, and the model parameters were set and analyzed using ANSYS Workbench software. Results: The average load of the L5-S2 alar internal fixation device was 86.9-111% higher than that of the L5-S1 fixation device when the internal bone of the S1 screw canal yielded. In the L5-S1 fixation model, the stress was concentrated in the tail of the S1 screw, and in the L5-S2 alar fixation model, the stress was concentrated in the titanium rod. In the L5-S2 alar fixation method, the internal deformation of the S1 screw track was scattered and uniform, while in the L5-S1 fixation method, local bone destruction in the front and back ends of the screw track was prone to occur due to the stress concentration. Conclusion: Extending fixation to the S2 wing can significantly improve internal fixation device stability and reduce the risk of intraoperative and postoperative fractures while avoiding injury to the sacroiliac joint, reducing the difficulty of surgery and the risk of injury to surrounding tissues. It is a reasonable plan for the treatment of moderate and severe lumbar spondylolisthesis with osteoporosis.

Morphometric Analysis of Lateral Masses of Axis Vertebrae in North Indians

Background and Objective. The lateral masses of axis have good cancellous bone quality beneath the articular surface of facets that make this area a good site for the insertion of an internal fixation device. Methods. 60 dry axis vertebrae were obtained for anatomic evaluation focused on pedicle, superior and inferior articular facets, and foramen transversarium. Based upon linear and angular parameters the mean, range, and standard deviation were calculated. Results. The mean length, width, and height of the pedicle were 21.61 ± 2.37 mm, 8.82 ± 2.43 mm, and 5.63 ± 2.06 mm. The mean pedicle superior angle and median angle were 23.3 and 32.2 degrees. The mean superior articular facet length, width, and external and internal height were 16.34 ± 1.56 mm, 14.35 ± 1.75 mm, 8.98 ± 1.36 mm, and 4.23 ± 0.81 mm. Depth of vertebral artery was 4.72 ± 0.83 mm. Mean inferior articular facet length and width were 11.13 ± 1.43 mm and 7.89 ± 1.30 mm. The mean foramen transversarium length and width were 5.11 ± 0.91 mm and 5.06 ± 1.23 mm. Conclusions. The study may provide information for the surgeons to determine the safe site of entry and trajectory for the screw implantation and also to avoid injuries to vital structures while operating around axis.