Impaction bone-grafting increases the holding power of cancellous screws in the femoral head : A pull-out study in human cadaver hips

Lenzner, Aleks; Kaur, Ikwinder Preet; Haviko, Tiit; Sõgel,; J, Gapejeva; Ereline, Jaan

doi:10.3109/17453679909000952

Cited by 7 publications

(5 citation statements)

References 10 publications

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“…For the human cadaveric femurs at present examined, tests yielded high linear correlation coefficients of sBMD and T-score with pull-out force (R 2 5 0.89 and 0.93 respectively), shear stress (R 2 5 0.89 and 0.93 respectively), and energy (R 2 5 0.79 and 0.82 respectively). This finding corroborates the more modest correlations of previous studies of cancellous bone screws extracted from the human cancellous bone of the femoral head (R 2 5 0.31) and the calcaneus (R 2 5 0.59) [28,33]. This may suggest that clinical bone scans of patients prior to any surgical fracture repair involving cancellous bone (such as the treatment of subcapital, cervical, or basicervical femoral neck fractures) may be predictive in the quality of screw purchase achieved and, hence, the overall success of the procedure.…”

Section: Implications For Clinical Practicesupporting

confidence: 91%

“…The cancellous screw average shear stress values for current 4GCF solid (2.84 ¡ 0.20 MPa), 4GCF cellular (4.31 ¡ 0.41 MPa), human femurs (4.66 ¡ 4.22 MPa), and finite element model (2.29 and 4.70 MPa) showed excellent overlap with the overall range from previous studies in which cancellous screws of 6.5 mm diameter were extracted from human cancellous bone. For the femoral head, average shear stresses have been reported to be 0.75 MPa [29], 3.99 ¡ 2.13 MPa [28], and 4.41 MPa [29]. For the distal femoral plateau, results achieved were 1.17 ¡ 1.34 MPa [30].…”

Section: Comparison With Previous Literaturementioning

confidence: 99%

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Cancellous bone screw purchase: A comparison of synthetic femurs, human femurs, and finite element analysis

Zdero

Olsen

Bougherara

et al. 2008

Proc Inst Mech Eng H

106

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Biomechanical assessments of orthopaedic fracture fixation constructs are increasingly using commercially available analogues such as the fourth-generation composite femur (4GCF). The aim of this study was to compare cancellous screw purchase directly between these surrogates and human femurs, which has not been done previously. Synthetic and human femurs each had one orthopaedic cancellous screw (major diameter, 6.5 mm) inserted along the femoral neck axis and into the spongy bone of the femoral head to a depth of 30 mm. Screws were removed to obtain pull-out force, shear stress, and energy values. The three experimental study groups (n = 6 femurs each) were the 4GCF with a 'solid' cancellous matrix, the 4GCF with a 'cellular' cancellous matrix, and human femurs. Moreover, a finite element model was developed on the basis of the material properties and anatomical geometry of the two synthetic femurs in order to assess cancellous screw purchase. The results for force, shear stress, and energy respectively were as follows: 4GCF solid femurs, 926.47 +/- 66.76 N, 2.84 +/- 0.20 MPa, and 0.57 +/- 0.04 J; 4GCF cellular femurs, 1409.64 +/- 133.36 N, 4.31 +/- 0.41 MPa, and 0.99 +/- 0.13 J; human femurs, 1523.29 +/- 1380.15N, 4.66 +/- 4.22 MPa, and 2.78 +/- 3.61J. No statistical differences were noted when comparing the three experimental groups for pull-out force (p = 0.413), shear stress (p = 0.412), or energy (p = 0.185). The 4GCF with either a 'solid' or 'cellular' cancellous matrix is a good biomechanical analogue to the human femur at the screw thread-bone interface. This is the first study to perform a three-way investigation of cancellous screw purchase using 4GCFs, human femurs, and finite element analysis.

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Section: Implications For Clinical Practicesupporting

confidence: 91%

Section: Comparison With Previous Literaturementioning

confidence: 99%

Cancellous bone screw purchase: A comparison of synthetic femurs, human femurs, and finite element analysis

Zdero

Olsen

Bougherara

et al. 2008

Proc Inst Mech Eng H

106

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“…The mean density for the osteoporotic bone simulation was 0.192 g/cm 3 (force of compression 3.33 Mpa) as indicated by the manufacturer and correlated to a calculated age of 94 years [40]. Lenzner [37] reported bone densities between 0.190 g/cm 3 and 0.394 g/cm 3 (mean 0.272 g/cm 3 ) in his studies and correlated the bone density with the ability of the hip screw to maintain fracture stability in human femoral heads using QCT-assisted analyses.…”

Section: Discussionmentioning

confidence: 99%

Biopolymer augmentation of the lag screw in the treatment of femoral neck fractures - a biomechanical in-vitro study

et al. 2010

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The cut-out of the sliding screw is one of the most common complications in the treatment of intertrochanteric fractures. The reasons for the cut-out are: a suboptimal position of the hip-screw in the femoral head, the type of fracture and poor bone quality. The aim of this study was to reproduce the cut-out event biomechanically and to evaluate the possible prevention of this event by the use of a biopolymer augmentation of the hip screw.Concerning the density and compression force of osteoporotic femoral bone polyurethane foam according to the terms of the Association for Standard Testing Material (ASTMF 1839-97) was used as test material. The polyurethane foam Lumoltan 200 with a compression force of 3.3 Mpa and a density of 0.192 g/cm3 was used to reproduce the osteoporotic bone of the femoral fragment (density 12 lbm/ft3). A cylinder of 50 mm of length and 50 mm of width was produced by a rotary splint raising procedure with planar contact.The axial load of the system was performed by a hydraulic force cylinder of a universal test machine type Zwick 1455, Ulm, Germany. The CCD-angle of the used TGN-System was preset at 130 degrees.The migration pattern of the hip screw in the polyurethane foam was measured and expressed as a curve of the distance in millimeter [mm] against the applied load in Newton [N] up to the cut-out point. During the tests the implants reached a critical changing point from stable to unstable with an increased load progression of steps of 50 Newton. This unstable point was characterized by an increased migration speed in millimeters and higher descending gradient in the migration curve. This peak of the migration curve served as an indicator for the change of the hip screw position in the simulated bone material. The applied load in the non-augmented implant showed that in this group for a density degree of 12 (0,192 g/cm3) the mean force at the failure point was 1431 Newton (± 52 Newton). In the augmented implant we found that the mean force at the failure point was 1987 Newton (± 84 Newton). This difference was statistically significant.In conclusion, the bone density is a significant factor for the stability of the hip screw implant. The osteosynthesis with screws in material with low density increases the chance for cut-out. A biopolymer augmented hip screw could significantly improve the stability of the fixation. The use of augmentation with a fast hardening bone replacement material containing polymer-ceramic changes the point of failure under axial load in the osteoporotic bone model and could significantly improve the failure point. Our study results indicate, that a decrease of failure in terms of cut-out can be achieved with polymer augmentation of hip screws in osteoporotic bones.

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“…To some extent, it is arched, so as to be convex in front. The distal portion is fairly cuboid in the form and is larger in comparison with the proximal portion [52]. The long shaft of the femur, i.e.…”

Section: Human Femurmentioning

confidence: 97%

Biomechanical development and analysis of a new carbon-fiber/flax/epoxy plate for repairing femur fractures

Bagheri¹

2022

Preprint

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Femur fracture at the tip of a total hip replacement (THR), commonly known as Vancouver B1 fracture, is mainly treated using rigid metallic bone plates, which may result in "stress shielding" leading to bone resorption and implant loosening. To minimize "stress shielding", a novel carbon fiber (CF)/Flax/Epoxy composite plate with a “sandwich structure” has been developed and characterized mechanically, biologically and biomechanically compared to a standard clinical metal plate. The CF/Flax/Epoxy composite material showed no cytotoxicity with no negative influence on the expression level of bone formation genes at all incubation time. The results of mechanical tests revealed a considerably high ultimate strength in tension (399.8 MPa), flexion (510.6 MPa) and fatigue loading (200-220 MPa). The composite plate showed higher elastic modulus in bending tests (57.4 GPa) compared to tension tests (41.7 GPa). The dynamic modulus (E*) was found to stay almost constant versus the number of cycles, which can be related to the contribution of both flax/epoxy and CF/epoxy laminae to the stiffness of the composite. The results of biomechanical assessment of the plate showed that the bone beneath the CF/Flax/Epoxy plate was the only area that had a significantly higher average surface stress (fractured = 2.10 ± 0.66 MPa; healed = 1.89±0.39 MPa) compared to bone beneath the metal plate (fractured = 1.shielding” effect. The CF/Flax/Epoxy plated femur had comparable axial stiffness (fractured = 645 ± 67 N/mm; healed = 1731 ± 109 N/mm) to the metal plated femur (fractured = 658 ± 69 N/mm; healed = 1751 ± 39 N/mm) (p=1.00). These results confirm that the new CF/Flax/Epoxy material could be a potential candidate for bone fracture plate applications as it shows good biocompatibility and considerably higher strength in tension, flexion and fatigue than actual clinical load level experienced by femur during daily normal activities. Moreover, it can simultaneously provide similar mechanical stiffness and lower “stress shielding” (i.e. higher bone stress) compared to commercially-used metal bone plates.18 ± 0.93 MPa; healed = 0.71 ± 0.24 MPa) (p<0.05), cause less “stress

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Impaction bone-grafting increases the holding power of cancellous screws in the femoral head : A pull-out study in human cadaver hips

Cited by 7 publications

References 10 publications

Cancellous bone screw purchase: A comparison of synthetic femurs, human femurs, and finite element analysis

Cancellous bone screw purchase: A comparison of synthetic femurs, human femurs, and finite element analysis

Biopolymer augmentation of the lag screw in the treatment of femoral neck fractures - a biomechanical in-vitro study

Biomechanical development and analysis of a new carbon-fiber/flax/epoxy plate for repairing femur fractures

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