Biomechanical Study Using the Finite Element Method of Internal Fixation in Pauwels Type III Vertical Femoral Neck Fractures

Noda, Masaharu; Saegusa, Yasuhiro; Takahashi, M; Tezuka, Daichi; Adachi, K.; Naoi, Kazuya

doi:10.5812/atr.23167

Cited by 23 publications

(25 citation statements)

References 13 publications

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“…In a study by Knobe et al,12) the average failure load of the rotationally stable screw-anchor (RoSA) system was 5,100 ± 750 N, whereas that for the 135° four-hole DHS was 3,000 ± 675 N and that for the 135° four-hole DHS-blade was 3,900 ± 75 N ( p = 0.002). Noda et al8) measured the stress applied to the medical femoral neck according to Pauwels type when vertical loading was applied. The highest stress was observed in type III.…”

Section: Resultsmentioning

confidence: 99%

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Biomechanical Evaluation of Internal Fixation of Pauwels Type III Femoral Neck Fractures: A Systematic Review of Various Fixation Methods

et al. 2019

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Background The purpose of this systematic review was to investigate various fixation methods or implants used in the treatment of Pauwels type III femoral neck fractures. Methods PubMed Central, OVID Medline, Cochrane Collaboration Library, Web of Science, Embase, and AHRQ databases were searched to identify relevant studies published until August 2017 with English language restriction. Studies were selected on the basis of the following inclusion criteria: biomechanical study of Pauwels type III femoral neck fractures and the use of dynamic hip screw (DHS) or multiple screw fixation or other devices for fixation of the fracture. Results A total of 15 studies were included in the systematic review. Eight studies were conducted using cadavers, six studies using sawbones, and one using a finite element model. During the mechanical testing, each study measured mechanical stiffness, failure to cyclic loading, failure to vertical loading of each fixation device. DHS was included in 11 studies, multiple screw fixation in 10 studies, and other devices in six studies. Baitner et al. and Samsami et al. reported that the mechanical stiffness of DHS was superior to three inverted triangular screw fixation. Hawks et al. and Gumustas et al. reported that using a transverse calcar screw can withstand vertical loading better than three inverted triangular screw fixation. In addition, there were some studies where instruments such as Intertan nail, locking plate or other devices showed excellent biomechanical properties. Conclusions There are a variety of methods and instruments for fixation of the Pauwels type III fractures. However, it is difficult to conclude that any method is more desirable because there are advantages and disadvantages to each method. Therefore, we should pay attention to the implant choice and consider adequate weight bearing affecting the stiffness of the implant.

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Section: Resultsmentioning

confidence: 99%

“…Therefore, stable fixation of a Pauwels type III femoral neck fracture with an angle greater than 70° is often difficult to achieve 13). To overcome this difficulty, various implants including the dynamic hip screw (DHS) and blade type DHS (DHS-blade) have been used for fixation of this type of fracture 45678910111213)…”

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confidence: 99%

Biomechanical Evaluation of Internal Fixation of Pauwels Type III Femoral Neck Fractures: A Systematic Review of Various Fixation Methods

et al. 2019

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“…We only adopted the one-legged stance configuration to examine the behavior of the proximal femur because our focus was to validate the model and make it possible to analyze the model with small implants. Recent studies using FEA prediction of the proximal femur with small implants have provided much important knowledge [ 18 – 23 ]; however, the validation was insufficient. Third, we did not compare mechanical fracture sites with FEA-predicted fracture sites because most mechanical fracture sites were not obvious macroscopically or with CT imaging.…”

Section: Discussionmentioning

confidence: 99%

“…Recently, a large number of studies using FEA of the proximal femur have been reported as a postoperative evaluation with small implants like screws, plates, and the femoral stem [ 18 – 23 ]. In future, these studies may be useful for preoperative planning to select the most suitable implant or fixation methods.…”

Section: Introductionmentioning

confidence: 99%

Prediction of fracture load and stiffness of the proximal femur by CT-based specimen specific finite element analysis: cadaveric validation study

Miura

Nakamura

Matsuura

et al. 2017

BMC Musculoskelet Disord

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BackgroundFinite element analysis (FEA) of the proximal femur has been previously validated with large mesh size, but these were insufficient to simulate the model with small implants in recent studies. This study aimed to validate the proximal femoral computed tomography (CT)-based specimen-specific FEA model with smaller mesh size using fresh frozen cadavers.MethodsTwenty proximal femora from 10 cadavers (mean age, 87.1 years) were examined. CT was performed on all specimens with a calibration phantom. Nonlinear FEA prediction with stance configuration was performed using Mechanical Finder (mesh,1.5 mm tetrahedral elements; shell thickness, 0.2 mm; Poisson’s coefficient, 0.3), in comparison with mechanical testing. Force was applied at a fixed vertical displacement rate, and the magnitude of the applied load and displacement were continuously recorded. The fracture load and stiffness were calculated from force–displacement curve, and the correlation between mechanical testing and FEA prediction was examined.ResultsA pilot study with one femur revealed that the equations proposed by Keller for vertebra were the most reproducible for calculating Young’s modulus and the yield stress of elements of the proximal femur. There was a good linear correlation between fracture loads of mechanical testing and FEA prediction (R2 = 0.6187) and between the stiffness of mechanical testing and FEA prediction (R2 = 0.5499). There was a good linear correlation between fracture load and stiffness (R2 = 0.6345) in mechanical testing and an excellent correlation between these (R2 = 0.9240) in FEA prediction.ConclusionsCT-based specimen-specific FEA model of the proximal femur with small element size was validated using fresh frozen cadavers. The equations proposed by Keller for vertebra were found to be the most reproducible for the proximal femur in elderly people.

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“…Hence, a valid computerized fracture model using a finite element method (FEM) might allow the investigation of the influence of critical mechanical factors on the stability of femoral neck fracture fixations. 17 This study aimed to investigate the mechanical stability obtained in femoral neck fracture fixation during the bone healing process for three different implants: cannulated screws (CSs), dynamic hip screw with de-rotational screw (DHS + DS) and proximal femoral locking plate (PFLP), using FEM. In order to compare the mechanical stability during different phases of the healing process, the progress of fracture consolidation was simulated by progressively increasing the friction coefficients between fracture fragments.…”

Section: Introductionmentioning

confidence: 99%

Stability of femoral neck fracture fixation: A finite element analysis

Samsami

Augat

Rouhi

2019

Proc Inst Mech Eng H

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Femoral neck fractures represent a relatively uncommon injury in the non-elderly population often resulting from high-energy trauma. Clinical outcome in these patients can be improved by optimizing surgical procedures and selecting appropriate fixation methods. The aim of this study was to develop a numerical fracture model to investigate the influence of critical mechanical factors on the stability of fixation methods for femoral neck fractures. The mechanical stability of fracture fixation was assessed through employing finite element models and simulating progressive consolidation of the fracture for a vertical femoral neck fracture (i.e. Pauwels type III in which the angle between the fracture line and the horizontal plane is greater than 70°). Mechanical performance was compared among three different fixation methods (cannulated screws, dynamic hip screw with de-rotational screw, and proximal femoral locking plate). Axial femoral head displacement varied from 2.3 mm for cannulated screws to 1.12 mm for proximal femoral locking plate, although dynamic hip screw with de-rotational screw indicated a value of 0.94 mm. Considering a consolidated fracture and full weight-bearing load case, average displacements of fracture fragments were obtained of about 1.5, 3 and 70 µm for dynamic hip screw with de-rotational screw, proximal femoral locking plate and cannulated screws methods, respectively. In terms of interfragmentary movements at the fracture site, outcomes of this study demonstrated that, in agreement with our previous experimental research, the dynamic hip screw with de-rotational screw implant is a more effective choice than cannulated screws and proximal femoral locking plate techniques for vertical femoral neck fractures in young patients. Thus, one may conclude that the use of dynamic hip screw with de-rotational screw, particularly during the early stages of bone healing, could provide suitable mechanical environments that facilitate direct bone formation and shorter healing times.

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Biomechanical Study Using the Finite Element Method of Internal Fixation in Pauwels Type III Vertical Femoral Neck Fractures

Cited by 23 publications

References 13 publications

Biomechanical Evaluation of Internal Fixation of Pauwels Type III Femoral Neck Fractures: A Systematic Review of Various Fixation Methods

Biomechanical Evaluation of Internal Fixation of Pauwels Type III Femoral Neck Fractures: A Systematic Review of Various Fixation Methods

Prediction of fracture load and stiffness of the proximal femur by CT-based specimen specific finite element analysis: cadaveric validation study

Stability of femoral neck fracture fixation: A finite element analysis

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