ABSTRACT
BACKGROUND:The traditional fixation method for femoral neck fractures is three hollow screws inverted triangle fixation,and the optimal fixation method for femoral neck fractures that have not achieved anatomical reduction is inconclusive. OBJECTIVE:To compare the biomechanical properties of cannulated screws internal fixation for sub-capitated femoral neck fracture with different reduction qualities based on finite element analysis. METHODS:The three-dimensional digital model was reconstructed using CT data of the proximal femur from a healthy male volunteer.The femur was modeled to sub-capitated femoral neck fractures.Fracture models were divided into anatomical reduction group,coxa vara group,and coxa valgus group.All fracture model groups were transferred using the standard group,screw depression group,and screw elevation group.A vertical downward stress of 1 400 N was applied to the femoral head at the top of the acetabulum.The displacement and stress distribution of the femur and internal fixator under different fixation methods were observed,and the maximum stress and displacement of the femur and fixator were compared. RESULTS AND CONCLUSION:(1)For anatomical reduction femoral neck fracture,the peak stress of fixation in the standard group,screw depression group and screw elevation group was 41.35,31.27 and 43.32 MPa,respectively.The maximum peak stress of the femur was found on the screw elevation group(28.58 MPa),and the standard group had the maximum peak displacement.(2)During hip varus,the stresses in the three subgroups were relatively dispersed and even.The peak stress of the femur in the standard group was the smallest,but the peak displacement was the largest.The stability of fixation might be poor.The peak displacement of the femur in the screw depression group was the smallest.(3)In the hip valgus,obvious screw stress concentration appeared in the screw depression group,and the peak displacement was the largest among the three subgroups,and an in-out-in phenomenon appeared.The peak stress of the screws in the screw elevation group was the largest among the three subgroups,but the peak displacement was the smallest.(4)It is concluded that for sub-capitated femoral neck fractures that are completely anatomically reduced,it is recommended to use standard inverted triangular nails for fixation.When the hip varus and hip valgus occur within the allowable range of the reduction standard,it is recommended to use the inverted triangle screw to fix it by rotating the corresponding angle in the same direction as the hip varus or valgus.
ABSTRACT
OBJECTIVE: To evaluate the effectiveness of the modified posterolateral counter-curved incision with double intermuscular approach for the treatment of posterolateral tibial plateau fractures. METHODS: A retrospective analysis was made on the clinical data of 32 patients with posterolateral tibial plateau fractures between September 2012 and October 2014. There were 22 males and 10 females, aged 19 to 55 years (mean, 40.5 years). The causes of injury included traffic accident in 17 cases, falling from height in 9 cases, and falling in 6 cases. They had fresh closed fracture; injury to hospitalization time was 3 hours to 5 days (mean, 2 days). According to Schatzker tibial plateau fracture classification criteria, 20 cases were rated as type II, and 12 cases as type III. All patients underwent a modified posterolateral counter-curved incision with double intermuscular approach to expose tibial posterolateral condyle and anterolateral condyle. After a good visual control of fracture reduction, the anterolateral and posterolateral fractures were fixed with two-dimensional buttress plate respectively. RESULTS: The incisions healed at stage I, with no major neurovascular injury. According to radiological assessment of the DeCoster score, the results were excellent in 21 cases, and fair in 11 cases. All of the 32 patients were followed up 18 to 30 months (mean, 20.5 months). The X-ray films showed that all patients obtained good fracture union, and the mean time of fracture union was 12.3 weeks (range, 10-16 weeks). No fixation failure or no obvious loss of articular surface reduction was observed during follow-up. The range of motion of the affected knees was 2-135° (mean, 120°). The mean American Hospital for Special Surgery (HSS) score was 90.05 (range, 83-96) at 18 months after operation. CONCLUSIONS: The modified posterolateral counter-curved incision with double intermuscular approach could fully expose posterolateral tibia plateau, and good fracture reduction and reliable fixation can be obtained under direct vision.
