Fibular grafting with cannulated hip screw fixation in late femoral neck fracture in young adults

Purpose: A series models of surgical internal fixation for femoral neck fracture of Pauwels II will be constructed by an innovative approach of finite element so as to determine the most stable fixation by comparison of their biomechanical performance. Method: Seventeen specimens of proximal femurs scanned by computed tomography in Digital Imaging and Communications in Medicine (DICOM) format were input onto Mimics rebuilding 3D models; their stereolithography (STL) format dataset were imported into Geomagic Studio (3D Systems, Rock Hill, South Carolina) for simulative osteotomy and non-uniform rational basis spline kartograph; the generated IGS dataset were interacted by UG to fit simulative 3D-solid models; 3 sorts of internal fixators were expressed in 3D model by ProE (PTC, Boston, Connecticut) program virtually. Processed by HyperMesh (Altair, Troy, Michigan), all compartments (fracture model + internal immobilization) were assembled onto 3 systems actually as: Dynamic hip screw (DHS) / Lag screw (LS) / DHS+LS. Eventually, a numerical model of finite elemental analysis was exported to ANSYS for solution. Result: Three models of internal fixations for femoral neck fracture of Pauwels II were established and validated effectively, the stress and displacement of each internal pin were analyzed, the advantages of each surgical therapy for femoral neck fracture of Pauwels II were compared and demonstrated synthetically as: “The contact stress of 3-LS-system was checked to be the least; the interfragmentary displacement of DHS+1-LS assemblages was assessed to be the least.” Conclusion: 3-LS-system is recommended to be a clinical optimization for Pauwels II femoral neck facture, by this therapeutic fixation mechanically, breakage of fixators, or secondary fracture rarely occurs.

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Calcar buttressed screw fixation for femoral neck fracture

International Journal of Research in Orthopaedics ◽

10.18203/issn.2455-4510.intjresorthop20185337 ◽

2018 ◽

Vol 5 (1) ◽

pp. 145

Author(s):

K. K. Arvind Manoj ◽

R. Karthik ◽

A. Vishnu Sankar

Keyword(s):

Femoral Neck ◽

Functional Outcome ◽

Femoral Neck Fracture ◽

Screw Fixation ◽

Femoral Neck Fractures ◽

Fixation Strength ◽

Harris Hip Score ◽

Average Period ◽

Excellent Outcome ◽

Neck Fracture

Background: The incidence of neck of femur fracture among elderly population is increasing day by day. Femoral neck fracture has always been an unsolved fracture as far as treatment and results are concerned. There are different views regarding the optimal method of internal ﬁxation in femoral neck fractures. Biomechanical data from literature suggest that calcar ﬁxation is superior to central screws placement. This study aims to analyse the functional and radiological outcome of femoral neck fractures treated by calcar buttressed screw fixation described by Filipov as biplane double supported screw fixation.Methods: This is a prospective study conducted in our institution from May 2015 to May 2018.The study included 43 patients (31 male, 12 female) with femoral neck fracture. Three 6.5-mm cannulated screws were laid in two medially diverging oblique planes. The distal and the middle screws were supported on the calcar. The distal screw had additional support on the posterior neck cortex. Patients were followed up for average period of 2 years. Functional outcome was evaluated using Harris Hip score.Results: Bone union occurred in 40 patients (93%) with average period of 3-4 months. 51.2% of cases had excellent outcome. 23.2% of cases had good and 16.3% of cases had fair outcome. 9.3% of cases ended with poor outcome. Non union was reported in 3 patients (7%) and AVN in one patient. Various factors like age, Garden and Pauwel fracture types, time of presentation and time of surgery were statistically significant to the final functional outcome in our study.Conclusions: By providing additional calcar buttress compared to conventional method, this technique of screw fixation enhances femoral neck fracture fixation strength and reduces the fixation failure.

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Modified F Configuration in the Treatment of Pauwels Type III Femoral Neck Fracture: a Finite Element Analysis

10.21203/rs.3.rs-135954/v1 ◽

2021 ◽

Author(s):

Shiyuan Lin ◽

Huizi Li ◽

Kai Tong ◽

Zihang Feng ◽

Gang Wang ◽

...

Keyword(s):

Finite Element ◽

Stress Distribution ◽

Femoral Neck ◽

Femoral Neck Fracture ◽

Femoral Neck Fractures ◽

Cannulated Screw ◽

Type Iii ◽

Neck Fracture ◽

Maximum Crack ◽

Hip Screw

Abstract Background: The optimal treatment of Pauwels type III femoral neck fracture in young patients remains a worldwide challenge in orthopedic surgery. Methods: Finite element models of four internal fixations were developed to treat Pauwels type III Femoral neck fracture: a: the traditional inverted triangular cannulated screw model, b: the F-technique cannulated screw model, c: the modified F-technique cannulated screw model using a fully threaded screw instead of a partially threaded distally, d: the dynamic hip screw coupled with anti-rotational screw model. Under the same conditions, finite element analyses were carried out to compare the displacement and von Mises stress distribution of four internal fixations and femurs, the maximum crack distances of the fracture surfaces, Z axis displacements of four models as well as the stress distribution in the subtrochanteric region. Results: The modified F-technique configuration resulted in a more stable fixation as compared to the other three approaches, with respect to the maximum displacement and stress peaks of femur and internal fixations, the maximum crack distances of the fracture surfaces, Z axis displacements of four configurations as well as the stress distribution in the subtrochanteric region.Conclusions: Our results suggested that modified F-technique configuration show a better performance in resisting shearing and rotational forces in treating Pauwels type III femoral neck fractures compared to those using traditional inverted triangular, the F-technique configuration or dynamic hip screw coupled with anti-rotational screw, providing a new choice for the treatment of femoral neck fractures.

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A Novel Device for Accurate Guide wire Placement in Cannulated Screw Fixation of Femoral Neck Fracture:A Pilot Study

10.21203/rs.3.rs-57323/v1 ◽

2020 ◽

Author(s):

bu-fang ren ◽

quan-ping Ma ◽

xin lv

Keyword(s):

Femoral Neck ◽

Femoral Neck Fracture ◽

Screw Fixation ◽

Kirschner Wire ◽

Operation Time ◽

Conventional Technique ◽

Novel Device ◽

Neck Fracture ◽

Guide Device ◽

Experimental Group

Abstract Background: Accurate placement of cannulated screws is the key to stable fixation of the femoral neck fracture. A novel device was developed to improve the accuracy of screw placement.Methods: 20 synthetic femoral bones were divided into conventional technique group and the experimental group. Three Kirschner wire were inserted into the femoral neck fracture by conventional technique or by the simple guide device. The operative time, total drilling times and fluoroscopic frequency were evaluated.Results: By using the guide device, the fluoroscopy and operation time of the experimental group were shorter that of the conventional method. The total drilling times with the simple guide device were significantly lower than the conventional technique group.Conclusions: This device can help trauma surgeons shorten the surgical time and reduce radiation exposure time. The use of this guide device can make screw fixation for femoral neck fracture easier.

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