scholarly journals Lateral migration resistance of screw is essential in evaluating bone screw stability of plate fixation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Xiaoreng Feng ◽  
Weichen Qi ◽  
Teng Zhang ◽  
Christian Fang ◽  
Hongfeng Liang ◽  
...  
Keyword(s):  
Dynamic Compression ◽  
Plate Fixation ◽  
Bone Screws ◽  
Superior Performance ◽  
Lateral Migration ◽  
Pullout Strength ◽  
Torsional Loading ◽  
Migration Resistance ◽  
Fixation Stability ◽  
The Stability

AbstractConventional evaluation of the stability of bone screws focuses on pullout strength, while neglecting lateral migration resistance. We measured pullout strength and lateral migration resistance of bone screws and determined how these characteristics relate to screw stability of locking plate (LP) and dynamic compression plate (DCP) fixation. Pullout strength and lateral migration resistance of individual bone screws with buttress, square, and triangular thread designs were evaluated in polyurethane foam blocks. The screw types with superior performance in each of these characteristics were selected. LP and DCP fixations were constructed using the selected screws and tested under cyclic craniocaudal and torsional loadings. Subsequently, the association between individual screws’ biomechanical characteristics and fixation stability when applied to plates was established. Screws with triangular threads had superior pullout strength, while screws with square threads demonstrated the highest lateral migration resistance; they were selected for LP and DCP fixations. LPs with square-threaded screws required a larger force and more cycles to trigger the same amount of displacement under both craniocaudal and torsional loadings. Screws with triangular and square threads showed no difference in DCP fixation stability under craniocaudal loading. However, under torsional loading, DCP fixation with triangular-threaded screws demonstrated superior fixation stability. Lateral migration resistance is the primary contributor to locking screw fixation stability when applied to an LP in resisting both craniocaudal and torsional loading. For compression screws applied to a DCP, lateral migration resistance and pullout strength work together to resist craniocaudal loading, while pullout strength is the primary contributor to the ability to resist torsional loading.

Biomechanical Testing of Locking and Nonlocking Plates in the Canine Scapula

2012 ◽  
Vol 48 (6) ◽  
pp. 372-378 ◽  
Author(s):  
Anthony E. Acquaviva ◽  
Emily I. Miller ◽  
David J. Eisenmann ◽  
Rick T. Stone ◽  
Karl H. Kraus
Keyword(s):  
Dynamic Compression ◽  
Plate Fixation ◽  
Biomechanical Testing ◽  
Osteoporotic Bone ◽  
Locking Plates ◽  
Pullout Strength ◽  
Modes Of Failure ◽  
Conventional Plate ◽  
String Of Pearls ◽  
Type Of Fracture

Locking plates have been shown to offer improved fixation in fractures involving either osteoporotic bone or bone with lesser screw pullout strength, such as thin and flat bones. Fractures of the scapular body are one type of fracture where the screw pullout strength using conventional plate fixation may not be sufficient to overcome physiologic forces. The purpose of this study was to compare the pullout strengths of locking plates to conventional nonlocking plates in the canine scapula. A 2.7 mm string of pearls plate (SOP) and a 2.7 mm limited contact dynamic compression plate (LC-DCP) were applied with similar divergent screws to the supraspinatus fossa of the scapula. Forces perpendicular to the plates were applied and both the loads at failure and modes of failure were recorded. No differences were noted in loads at failure between the two plating systems. Although the modes of failure were not significantly different, the SOP constructs tended to fail more often by bone slicing and coring, whereas the LC-DCP constructs failed primarily by screw stripping. Neither of the plate systems used in this study demonstrated a distinct mechanical advantage. The application and limitations of locking plate systems in various clinical situations require further study.

Atypical Femoral Fracture in McCune-Albright Syndrome

2020 ◽  
Vol 7 (3) ◽  
pp. 147-152
Author(s):  
Salman Ghaffari ◽  
◽  
Mehran Razavipour ◽  
Parastoo Mohammad Amini ◽  
◽  
...  
Keyword(s):  
Femoral Fracture ◽  
Dynamic Compression ◽  
Plate Fixation ◽  
Medullary Canal ◽  
Mccune Albright Syndrome ◽  
Café Au Lait Spots ◽  
History Of ◽  
Albright Syndrome ◽  
Mccune Albright

McCune-Albright Syndrome (MAS) is characterized by endocrinopathies, café-au-lait spots, and fibrous dysplasia. Bisphosphonates are the most prescribed treatment for reducing the pain but their long-term use has been associated with atypical fractures of cortical bones like femur in patients. We present a 23-year-old girl diagnosed with MAS. She had an atypical mid-shaft left femoral fracture that happened during simple walking. She also had a history of long-term use of alendronate. Because of the narrow medullary canal, we used 14 holes hybrid locking plate for the lateral aspect of the thigh to fix the fracture and 5 holes dynamic compression plate (instead of the intramedullary nail) in the anterior surface to double fix it, reducing the probability of device failure. With double plate fixation and discontinuation of alendronate, the complete union was achieved five months after surgery

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 A biomechanical comparison of 3.5 locking compression plate fixation to 3.5 limited contact dynamic compression plate fixation in a canine cadaveric distal humeral metaphyseal gap model

2009 ◽  
Vol 22 (04) ◽  
pp. 1-8 ◽  
Author(s):  
O. Lanz ◽  
R. McLaughlin ◽  
S. Elder ◽  
S. Werre ◽  
D. Filipowicz
Keyword(s):  
Axial Compression ◽  
Dynamic Testing ◽  
Dynamic Compression ◽  
Plate Fixation ◽  
Locking Compression Plate ◽  
Locking Plates ◽  
Gap Model ◽  
Static Compression ◽  
Dynamic Compression Plate ◽  
Compression Plate

Summary3.5 locking compression plate (LCP) fixation was compared to 3.5 limited contact dynamic compression plate (LC-DCP) fixation in a canine cadaveric, distal humeral metaphyseal gap model. Thirty paired humeri from adult, large breed dogs were separated into equal groups based on testing: static compression, cyclic compression, and cyclic torsion. Humeral constructs stabilized with LCP were significantly stiffer than those plated with LCDCP when loaded in static axial compression (P = 0.0004). When cyclically loaded in axial compression, the LCP constructs were significantly less stiff than the LC-DCP constructs (P = 0.0029). Constructs plated with LCP were significantly less resistant to torsion over 500 cycles than those plated with LC-DCP (P<0.0001). The increased stiffness of LCP constructs in monotonic loading compared to constructs stabilised with non-locking plates may be attributed to the stability afforded by the plate-screw interface of locking plates. The LCP constructs demonstrated less stiffness in dynamic testing in this model, likely due to plate-bone offset secondary to non-anatomic contouring and occasional incomplete seating of the locking screws when using the torque-limiting screw driver. Resolution of these aspects of LCP application may help improve the stiffness of fixation in fractures modeled by the experimental set-up of this investigation.

scholarly journals Modified supracondylar dome osteotomy: our experience in 11 children

2017 ◽  
Vol 3 (4) ◽  
pp. 766
Author(s):  
Abhinav . ◽  
Ajoy Kumar Manav ◽  
Arjun Singh
Keyword(s):  
Posterior Approach ◽  
Plate Fixation ◽  
Excellent Result ◽  
Older Children ◽  
Supracondylar Fractures ◽  
Loss Of Correction ◽  
Dome Osteotomy ◽  
K Wires ◽  
The Stability ◽  
Supracondylar Dome Osteotomy

<p class="abstract"><strong>Background:</strong> <span lang="EN-IN">The present retrospective study was done with 11 children having cubitus varus following supracondylar fractures to access the stability of modified domeosteotomy and its fixation with k-wires in older children.</span></p><p class="abstract"><strong>Methods:</strong> <span lang="EN-IN">11 children, 7 males &amp; 4 females were included in the study. The osteotomy was performed through posterior approach. The triangular wedge rotated inside the notch was inherently stable and also fixed with k-wires. Patients were followed at regular intervals. K wires were removed at 6 weeks and the physiotherapy started</span>.<strong></strong></p><p class="abstract"><strong>Results:</strong> <span lang="EN-IN">The correction obtained under vision was well maintained post operatively in 10 out of 11 cases. In only one case there was back out of k-wires and loss of correction. 5 cases had excellent result followed by 4 good and one fair result. </span></p><p class="abstract"><strong>Conclusions:</strong> <span lang="EN-IN">Modified dome osteotomy performed through posterior approach and fixed with k-wires gives good results. Removal of the k-wires is simple. However, in children above 14 years plate fixation might be better to prevent loss of correction.</span></p>

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