scholarly journals Conventional versus helical blade screw insertion following the removal of the femoral head screw: a biomechanical evaluation using trochanteric gamma 3 locking nail versus PFN antirotation

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Hong Man Cho ◽  
Kwang Min Park ◽  
Tae Gon Jung ◽  
Ji Yeon Park ◽  
Young Lee
Keyword(s):  
Experimental Models ◽  
Biomechanical Study ◽  
Original Model ◽  
Screw Insertion ◽  
Rotational Strength ◽  
Helical Blade ◽  
Locking Nail ◽  
Biomechanical Evaluation ◽  
Hip Screw ◽  
Rotational Strengths

Abstract Objective When a hip screw needs to be changed, choosing between the conventional (C-type) and helical blade (H-type) types is difficult. In this biomechanical study, we compared these two screw types relative to the type of the initial screw used. Methods C- or H-type screws were inserted (leading screw) in three types of polyurethane bone models (Sawbone, Pacific Research Laboratories, Inc., Washington, USA: 130 × 180 × 40 mm) of different bone mineral densities (pounds per cubic feet [PCF] 5, 80 kg/m3; PCF 10, 160 kg/m3; and PCF 15, 240 kg/m3), and then successively or alternately inserted (following screw) after the leading screw removal. An original model (original C and H) of a leading screw without removal was created as a control. The strengths of resistance to pullout (PO) and rotational stress were measured. For each experimental condition, there were 30 experimental models. Results The original C screw was superior in PO strength, and the original H-type screw was superior in rotational strength. When the C- or H-type screw was the leading screw, using the C-type screw again as the following screw (C1-C2, H1-C2) showed the greatest resistance to PO, and using the H-type screw as the following screw (C1-H2, H1-H2) showed superior resistance to rotational strength. However, the rotational strength of the C2 screw decreased by more than 50% compared with that of the original C screw. Moreover, the PO and rotational strengths of the H2 screw decreased to less than 30% overall compared with those of the original H screw. Conclusion The H-type screw should be used for second-time screw insertion procedures in cases where it is difficult to choose between PO and rotational strengths.

Helical blade versus sliding hip screw for treatment of unstable intertrochanteric hip fractures: A biomechanical evaluation

Injury ◽  
2006 ◽  
Vol 37 (10) ◽  
pp. 984-989 ◽  
Author(s):  
Eric Strauss ◽  
Joshua Frank ◽  
Jason Lee ◽  
Frederick J. Kummer ◽  
Nirmal Tejwani
Keyword(s):  
Hip Fractures ◽  
Sliding Hip Screw ◽  
Helical Blade ◽  
Biomechanical Evaluation ◽  
Hip Screw

scholarly journals A Biomechanical Study Comparing Helical Blade with Screw Design for Sliding Hip Fixations of Unstable Intertrochanteric Fractures

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Qiang Luo ◽  
Grace Yuen ◽  
Tak-Wing Lau ◽  
Kelvin Yeung ◽  
Frankie Leung
Keyword(s):  
Intertrochanteric Fracture ◽  
Biomechanical Properties ◽  
Biomechanical Study ◽  
Mechanical Compression ◽  
Rotational Displacement ◽  
Screw Design ◽  
Cutting Out ◽  
Helical Blade ◽  
Hip Screw ◽  
Posterior Position

Dynamic hip screw (DHS) is a well-established conventional implant for treating intertrochanteric fracture. However, revision surgery sometimes still occurs due to the cutting out of implants. A helical blade instead of threaded screw (DHS blade) was designed to improve the fixation power of the osteoporotic intertrochanteric fracture. In this study, the biomechanical properties of DHS blade compared to the conventional DHS were evaluated using an unstable AO/OTA 31-A2 intertrochanteric fracture model. Fifty synthetic proximal femoral bone models with such configuration were fixed with DHS and DHS blade in five different positions: centre-centre (CC), superior-centre (SC), inferior-center (IC), centre-anterior (CA), and centre-posterior (CP). All models had undergone mechanical compression test, and the vertical and rotational displacements were recorded. The results showed that DHS blade had less vertical or rotational displacement than the conventional DHS in CC, CA, and IC positions. The greatest vertical and rotational displacements were found at CP position in both groups. Overall speaking, DHS blade was superior in resisting vertical or rotational displacement in comparison to conventional DHS, and the centre-posterior position had the poorest performance in both groups.

A Biomechanical Evaluation of Three Forms of Internal Fixation Used in Ankle Arthrodesis

1994 ◽  
Vol 15 (6) ◽  
pp. 297-300 ◽  
Author(s):  
Michael P. Dohm ◽  
James B. Benjamin ◽  
Jeffrey Harrison ◽  
John A. Szivek
Keyword(s):  
Internal Fixation ◽  
Plate Fixation ◽  
Ankle Arthrodesis ◽  
Biomechanical Study ◽  
The Other ◽  
Fixation Failure ◽  
Plate Group ◽  
Biomechanical Evaluation ◽  
The Stability ◽  
Fibular Strut

A biomechanical study was undertaken to evaluate the relative stability of three types of internal fixation used for ankle arthrodesis. Crossed screw fixation, RAF fibular strut fixation, and T-plate fixation were tested in 30 cadaver ankles using an MTS machine. T-plate fixation consistantly provided the stiffest construct when compared with the other types of fixation. Failure occurred by distraction of bony surfaces, posterior to the plane of fixation, in the crossed screw and RAF groups. In contrast, failure in the T-plate group occurred through compression of bone anterior to the midcoronal plane of the tibia. Although the stability of fixation is only one factor in determining the success or failure of ankle arthrodesis, the results of this study would support T-plate fixation over the other forms tested.

scholarly journals Preoperative and Postoperative Oxygen Saturation in the Elderly following Spinal or General Anaesthesia—An Audit of Current Practice

1994 ◽  
Vol 22 (2) ◽  
pp. 150-154 ◽  
Author(s):  
A. G. Brown ◽  
A. R. Visram ◽  
R. D. M. Jones ◽  
M. G. Irwin ◽  
J. Bacon-Shone
Keyword(s):  
Elderly Patients ◽  
Oxygen Saturation ◽  
Signal Amplitude ◽  
The Elderly ◽  
Analysis Data ◽  
General Anaesthetic ◽  
Fractured Neck Of Femur ◽  
Neck Of Femur ◽  
Screw Insertion ◽  
Hip Screw

We have compared the incidence of preoperative and postoperative oxygen desaturation in 20 elderly patients undergoing dynamic hip screw insertion for fractured neck of femur, allocated randomly to two groups to receive subarachnoid anaesthesia (SA, n = 10) or a general anaesthetic (GA, n = 10). Oximetry data were recorded during the preoperative night and the first 48 hours after surgery using Satmaster.™ Data associated with zero amplitude signal were automatically invalidated by the software and decreases in SpO2 which were preceded by contemporaneous changes in signal amplitude which conformed to a previously described template were assumed to be artefactual and were discarded from final data analysis. Data demonstrated a wide interpatient variability. However, those patients who desaturated preoperatively continued to do so in the postoperative period. The differences between the preoperative and postoperative oximetry profiles were examined for each patient and demonstrated a significantly longer time spent with SpO2 <90% in the GA group compared with the SA group, in all the recorded time periods, except on the day of surgery. The SA group showed an improvement in oxygen saturation postoperatively when compared to the preoperative night, spending less time with an SpO2 <85%. We conclude that the subarachnoid anaesthetic technique was associated with a lower incidence of postoperative oximetry desaturation when compared with general anaesthetic for these elderly patients undergoing repair of fractured neck of femur.

Sliding hip screw versus sliding helical blade for intertrochanteric fractures

2015 ◽  
Vol 97-B (3) ◽  
pp. 398-404 ◽  
Author(s):  
C. Fang ◽  
T. W. Lau ◽  
T. M. Wong ◽  
H. L. Lee ◽  
F. Leung
Keyword(s):  
Intertrochanteric Fractures ◽  
Sliding Hip Screw ◽  
Helical Blade ◽  
Hip Screw

Biomechanical Evaluation of Different Designs of Glenospheres in the SMR Reverse Shoulder Prosthesis: Micromotion of the Baseplate and Risk of Loosening

2010 ◽  
Vol 2 (2) ◽  
pp. 94-99 ◽  
Author(s):  
Peter C. Poon ◽  
Justin Chou ◽  
Darryl Young ◽  
Sharif F. Malak ◽  
Iain A. Anderson
Keyword(s):  
Shear Force ◽  
Reverse Shoulder Arthroplasty ◽  
Biomechanical Study ◽  
Shoulder Prosthesis ◽  
Reverse Shoulder Prosthesis ◽  
Scapular Notching ◽  
Uncemented Prosthesis ◽  
Biomechanical Evaluation ◽  
Glenoid Baseplate

Background Early outcomes of reverse shoulder arthroplasty have been encouraging. Scapular notching remains a major concern. In an attempt to reduce this problem, newer glenospheres are available. This biomechanical study performed in vitro, assessed the micromotions of baseplate in different designs of glenospheres and the relative risk of loosening. Methods A dynamic shear force was applied to each type of glenosphere in various angles of abduction. The micromotion of the glenoid baseplate after 1000 cycles of dynamic loading was measured and compared. Results Eccentric glenospheres were shown to have increased micromotion compared to the concentric designs of the same size. The greatest baseplate micromotion (26.83 μm) was well within the accepted limit for osseous in growth into uncemented prosthesis. Discussion We therefore conclude that the magnitude of the increased micromotion is small and is not expected to adversely affect osseous in growth onto the glenoid baseplate.

PEDICLE SCREW CONVERGENCE IMPACT ON THE STABILITY OF TRANSPEDICULAR FIXATION SPINE MODEL IN CYCLIC LOADING: BIOMECHANICAL STUDY

2015 ◽  
Vol 15 (05) ◽  
pp. 1550078
Author(s):  
JOSEF VCELAK ◽  
PETR TICHÝ ◽  
TOMÁŠ BOUDA ◽  
JIŘÍ CHOMIAK ◽  
LADISLAV TÓTH
Keyword(s):  
Cyclic Loading ◽  
Biomechanical Study ◽  
Testing System ◽  
Structural Failure ◽  
Screw Insertion ◽  
Transpedicular Fixation ◽  
Measurement Results ◽  
Spine Model ◽  
The Stability ◽  
Cell Data

The principle of this study is experimental measurement and description of behavior of transpedicular fixation during cyclic loading due to convergence of screw insertion. Investigations were made of three configurations of assemblies of posterior stabliization with converging screws at 0°, 20° and 40°. The experiment was inspired ASTM Standard F1717 and modified to minimize the effect of other parameters. The MTS 858.2 Mini Bionix testing system was used during the experiment, in conjunction with the Interface 1010ACK load cell. Data processing and analysis were carried out by Matlab R 20102b, MathWorks. The probed assemblies were cyclically loaded until structural failure occurred, always at the screwbone (or PUR block) interface, i.e., the "windshield wiper" effect. The measurement results show that while the rigidity of the assembly increases with increased convergence of transpedicular screws, they also indicate an increased initial rate of assembly damage accumulation, together with assembly failure during a reduced number of cyclic loading cycles. The mechanical behavioral study of transpedicular fixation is limited by the conditions of simplification of interpretation of complex movements and spinal pathophysiology in the attempt to minimize the effect of other parameters and exaggerated measurements.

Sign in / Sign up

Export Citation Format

Share Document