scholarly journals A biomechanical comparison of two screw fixation methods in a Letenneur type I Hoffa fracture

2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Shu-Hsin Yao ◽  
Wei-Ren Su ◽  
Kai-Lan Hsu ◽  
Yueh Chen ◽  
Chih-Kai Hong ◽  
...  
Keyword(s):  
Screw Fixation ◽  
Type I ◽  
Fixation Methods ◽  
Hoffa Fracture ◽  
Biomechanical Comparison

scholarly journals S2 Alar Iliac Screw and S1 Pedicle Screw Fixation for the Treatment of Sacral Fractures : A Finite Element Study

2021 ◽  
Author(s):  
Jianxiong Zheng ◽  
Xiaoreng Feng ◽  
Jie Xiang ◽  
Fei Liu ◽  
Frankie K L Leung ◽  
...  
Keyword(s):  
Finite Element ◽  
Pedicle Screw ◽  
Screw Fixation ◽  
Relative Displacement ◽  
Pedicle Screw Fixation ◽  
Fe Model ◽  
Type I ◽  
Vertical Stiffness ◽  
Fixation Methods ◽  
Sacral Fractures

Abstract Background: Five different sacral fracture fixation methods were compared using finite element (FE) analysis to study their biomechanical characteristics.Methods: Denis type I sacral fractures were created by FE modeling. Five different fixation methods for the posterior pelvic ring were simulated: sacroiliac screw (SIS), lumbopelvic fixation (LPF), transiliac internal fixator (TIFI), S2-alar-iliac (S2AI) screw and S1 pedicle screw fixation (S2AI-S1), and S2AI screw and contralateral S1 pedicle screw fixation (S2AI-CS1). Four different loading methods were implemented in sequence to simulate the force in standing, flexion, right bending, and left twisting, respectively. Vertical stiffness, relative displacement, and change in relative displacement were recorded and analyzed.Results: As predicted by the FE model, the vertical stiffness of the five groups in descending order were S2AI-S1, SIS, S2AI-CS1, LPF, TIFI. In terms of relative displacement, S2AI-S1 and S2AI-CS1 groups displayed a smaller mean relative displacement, although the S2AI-CS1 group exhibited greater displacement in the upper sacrum than the S2AI-S1 group. The SIS group displayed a moderate mean relative displacement, although the displacement of the upper sacrum was smaller than that of the S2AI-CS1 group. The LPF and TIFI groups displayed larger mean relative displacements. In terms of change in relative displacement, the TIFI and LPF groups displayed the greatest fluctuations in their motion, while the SIS, S2AI-S1, and S2AI-CS1 groups displayed smaller fluctuations.Conclusion: Compared with SIS, unilateral LPF and TIFI, S2AI-S1 displayed the greatest biomechanical stability of the FE models and can be used as a new method for the treatment of sacral fractures. When the S1 pedicle screw insertion point on the affected side is damaged, S2AI-CS1 can be used as a good alternative to S2AI-S1.

scholarly journals S2-alar-iliac screw and S1 pedicle screw fixation for the treatment of non-osteoporotic sacral fractures: a finite element study

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Jianxiong Zheng ◽  
Xiaoreng Feng ◽  
Jie Xiang ◽  
Fei Liu ◽  
Frankie K. L. Leung ◽  
...  
Keyword(s):  
Finite Element ◽  
Pedicle Screw ◽  
Screw Fixation ◽  
Relative Displacement ◽  
Pedicle Screw Fixation ◽  
Sacral Fracture ◽  
Type I ◽  
Vertical Stiffness ◽  
Fixation Methods ◽  
Sacral Fractures

Abstract Background Five different sacral fracture fixation methods were compared using finite element (FE) analysis to study their biomechanical characteristics. Methods Denis type I sacral fractures were created by FE modeling. Five different fixation methods for the posterior pelvic ring were simulated: sacroiliac screw (SIS), lumbopelvic fixation (LPF), transiliac internal fixator (TIFI), S2-alar-iliac (S2AI) screw and S1 pedicle screw fixation (S2AI-S1) and S2AI screw and contralateral S1 pedicle screw fixation (S2AI-CS1). Four different loading methods were implemented in sequence to simulate the force in standing, flexion, right bending and left twisting, respectively. Vertical stiffness, relative displacement and change in relative displacement were recorded and analyzed. Results As predicted by the FE model, the vertical stiffness of the five groups in descending order was S2AI-S1, SIS, S2AI-CS1, LPF and TIFI. In terms of relative displacement, groups S2AI-S1 and S2AI-CS1 displayed a lower mean relative displacement, although group S2AI-CS1 exhibited greater displacement in the upper sacrum than group S2AI-S1. Group SIS displayed a moderate mean relative displacement, although the displacement of the upper sacrum was smaller than the corresponding displacement in group S2AI-CS1, while groups LPF and TIFI displayed larger mean relative displacements. Finally, in terms of change in relative displacement, groups TIFI and LPF displayed the greatest fluctuations in their motion, while groups SIS, S2AI-S1 and S2AI-CS1 displayed smaller fluctuations. Conclusion Compared with SIS, unilateral LPF and TIFI, group S2AI-S1 displayed the greatest biomechanical stability of the Denis type I sacral fracture FE models. When the S1 pedicle screw insertion point on the affected side is damaged, S2AI-CS1 can be used as an appropriate alternative to S2AI-S1.

An Uncommon Trauma: Hoffa's Fracture Associated with Tibial Avulsion Fracture of the Posterior Cruciate Ligament

2021 ◽  
Author(s):  
Bertan Cengiz ◽  
Sinan Karaoglu
Keyword(s):  
Posterior Cruciate Ligament ◽  
Avulsion Fracture ◽  
Cruciate Ligament ◽  
Easy Access ◽  
Lateral Condyle ◽  
Type I ◽  
Hoffa Fracture ◽  
Tibial Avulsion Fracture ◽  
Additional Stability ◽  
Buttress Plate

Abstract BackgroundSince Hoffa fractures are usually the result of high-energy injuries, many additional accompanying injuries have been described. This is the first paper representing the lateral condyle Hoffa fracture accompanying tibial avulsion fracture of the posterior cruciate ligament (PCL).Case PresentationA 42-years-old male presented with swelling and instability in his left knee after falling during parachute landing. He was diagnosed with simultaneous Letenneur Type I lateral condyle Hoffa fracture and tibial avulsion fracture of the PCL. He was operated on with a single posterior incision for both fractures. Multiple cannulated lag screws were used for the fixation of the Hoffa fracture, and a buttress plate was used for additional stability. PCL avulsion fracture was fixed with a cannulated screw with a washer. The patient was allowed for full-weight-bearing and range of motion at the sixth week after the operation. No complications occurred during follow-up.ConclusionCare should be taken in terms of additional injuries that may accompany Hoffa fractures. The posterior approach allows easy access to both fractures with a single incision. Using a buttress plate after the fixation of the Hoffa fracture with multiple lag screws provides additional stability.

Computed Tomography and Biomechanical Comparison between Trans-Articular Screw Fixation and 2 Polymethylmethacrylate Cemented Constructs for Ventral Atlantoaxial Stabilization

2018 ◽  
Vol 31 (05) ◽  
pp. 344-355 ◽  
Author(s):  
Noël Moens ◽  
Luis Gaitero ◽  
Alex zur Linden ◽  
Fiona James ◽  
Gabrielle Monteith ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Screw Fixation ◽  
Biomechanical Properties ◽  
The Past ◽  
Stabilization Methods ◽  
Surgical Options ◽  
Atlantoaxial Stabilization ◽  
Ct Data ◽  
Biomechanical Comparison ◽  
Surgical Guidelines

Objectives Canine ventral atlantoaxial stabilization methods have been constantly evolving over the past few decades. Yet, proper experimental data comparing the feasibility and biomechanical properties of currently available surgical options are lacking. The aims of this study were (1) to describe and compare the safety profiles and biomechanical properties of three ventral atlantoaxial stabilization methods; and (2) to test whether recently reported optimal implant definitions constitute reasonable guidelines. Methods Three types of atlantoaxial stabilization including trans-articular screw fixation (TSF) and two cemented constructs (MI5 and MI6) were performed in 21 Beagle cadavers. Post-surgical computed tomography (CT) images of the constructs and biomechanical data were then generated and statistically analysed. Results The CT data revealed that TSF achieved significantly better apposition than cemented constructs. Out of 91 screws positioned, 4.4% were graded as dangerous and 86.8% as optimal. Optimal positioning was most challenging to obtain for mono-cortical screws. Analysis of biomechanical data suggested that all three techniques could likely achieve similar rates of atlantoaxial fusion when submitted to physiological loads but also that cemented constructs were less prone to failure compared with TSF. Clinical Significance This study provides evidence that all three techniques are technically feasible and biomechanically viable but also that the evaluated surgical guidelines could be improved.

scholarly journals The Fibular Intramedullary Nail Versus Locking Plate and Lag Screw Fixation in the Management of Unstable Elderly Ankle Fractures: A Cadaveric Biomechanical Comparison

2020 ◽  
Vol 34 (11) ◽  
pp. e401-e406
Author(s):  
Thomas H. Carter ◽  
Robert Wallace ◽  
Samuel A. Mackenzie ◽  
William M. Oliver ◽  
Andrew D. Duckworth ◽  
...  
Keyword(s):  
Intramedullary Nail ◽  
Locking Plate ◽  
Screw Fixation ◽  
Ankle Fractures ◽  
Lag Screw ◽  
Biomechanical Comparison
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