Sind winkelstabile Plattensysteme mit elastischen Eigenschaften für die Stabilisierung der Oberarmkopffraktur vorteilhaft? / Eine in-vitro biomechanische Untersuchung

2004 ◽  
Vol 49 (12) ◽  
Author(s):  
M. H Hessmann ◽  
W Sternstein ◽  
D Mehler ◽  
J Korner ◽  
A Hofmann ◽  
...  
Keyword(s):  
Proximal Humerus ◽  
Axial Loading ◽  
Biomechanical Properties ◽  
Torsional Stiffness ◽  
Unstable Fracture ◽  
Beneficial Effects ◽  
Increased Risk ◽  
Cutting Out ◽  
Load To Failure

AbstractWinkelstabile Platten werden mit zunehmender Häufigkeit zur Stabilisierung von Oberarmkopfbrüchen verwendet. Rigide Implantate führen bei osteoporotischen Knochenverhältnissen u. U. aber häufiger zum Versagen. Um den Effekt der Implantatelastizität zu beurteilen wurden in einer in-vitro Studie die biomechanischen Eigenschaften eines rigiden und eines elastischen winkelstabilen Plattensystems vergleichend analysiert. An 8 Humeruspaaren wurde eine instabile subkapitale Fraktur simuliert. Die Proben wurden axial- und torsions-belastet. Analysiert wurden die Steifigkeit, das Setzverhalten unter Dauerlast und die Versagensbelastung.Das elastische Plattensystem kennzeichnete sich durch eine geringere Torsionssteifigkeit und eine größere Verformung unter Axial- und Torsionsbelastung. Die Proben versagten früher als beim rigiden Plattenystem.Unter biomechanischen Gesichtspunkten bieten Implantate mit elastischen Eigenschaften am Oberarmkopf somit keine Vorteile. There is a recent interest for the use of angle-fixed plates in the management of proximal humerus fractures. Rigid implants might be associated with an increased risk of cutting-out. In order to analyse the potential beneficial effects of the implant elasticity on fracture fixation, the biomechanical properties of a rigid and an elastic angle-fixed plating system were assessed in an experimental study. An unstable fracture of the surgical neck was created in 8 pairs of human humeri. Specimens were subjected to axial loading and torque. Stiffness, subsidence and load to failure were assessed.The implant with elastic properties was characterized by a lower torsional stiffness and a higher subsidence during axial loading and torque. This implant failed at lower loads than the rigid implant did.Elastic implant properties of angle-fixed plates have shown not to be advantageous for the management of fractures of the proximal humerus.

Diabetes and Heart Failure: Is it Hyperglycemia or Hyperinsulinemia?

2020 ◽  
Vol 18 (2) ◽  
pp. 148-157 ◽  
Author(s):  
Triantafyllos Didangelos ◽  
Konstantinos Kantartzis
Keyword(s):  
Heart Failure ◽  
Insulin Treatment ◽  
Close Association ◽  
Adverse Outcomes ◽  
Negative Effects ◽  
Beneficial Effects ◽  
Appropriate Treatment ◽  
Increased Risk ◽  
Treatment Of Diabetes

The cardiac effects of exogenously administered insulin for the treatment of diabetes (DM) have recently attracted much attention. In particular, it has been questioned whether insulin is the appropriate treatment for patients with type 2 diabetes mellitus and heart failure. While several old and some new studies suggested that insulin treatment has beneficial effects on the heart, recent observational studies indicate associations of insulin treatment with an increased risk of developing or worsening of pre-existing heart failure and higher mortality rates. However, there is actually little evidence that the associations of insulin administration with any adverse outcomes are causal. On the other hand, insulin clearly causes weight gain and may also cause serious episodes of hypoglycemia. Moreover, excess of insulin (hyperinsulinemia), as often seen with the use of injected insulin, seems to predispose to inflammation, hypertension, dyslipidemia, atherosclerosis, heart failure, and arrhythmias. Nevertheless, it should be stressed that most of the data concerning the effects of insulin on cardiac function derive from in vitro studies with isolated animal hearts. Therefore, the relevance of the findings of such studies for humans should be considered with caution. In the present review, we summarize the existing data about the potential positive and negative effects of insulin on the heart and attempt to answer the question whether any adverse effects of insulin or the consequences of hyperglycemia are more important and may provide a better explanation of the close association of DM with heart failure.

scholarly journals Biomechanical testing of trans-humeral all-suture anchors for rotator cuff repair

2018 ◽  
Vol 11 (1_suppl) ◽  
pp. 77-85
Author(s):  
Mikel Aramberri-Gutiérrez ◽  
Amaia Martínez-Menduiña ◽  
Simon Boyle ◽  
Maria Valencia
Keyword(s):  
Rotator Cuff ◽  
Proximal Humerus ◽  
Biomechanical Testing ◽  
Tensile Load ◽  
Biomechanical Properties ◽  
Rotator Cuff Tears ◽  
Suture Anchors ◽  
Load To Failure ◽  
Insertion Sites ◽  
Number Of Cycles

Background Rotator cuff tears are one of the most common causes of shoulder pain. All-suture anchors are increasingly being used in the arthroscopic repair of rotator cuff tears. The purpose of this experimental study is to evaluate the biomechanical properties of all-suture anchors at different insertion sites in the proximal humerus relevant to rotator cuff repairs and the remplissage procedure. Methods Sixteen cadaveric shoulders were used for the study. Four all-suture anchors were inserted in each proximal humerus at common anchor insertion sites on the rotator cuff footprint and a simulated Hill–Sachs defect. Cyclic loading and load-to-failure tests were undertaken. The number of cycles, load to failure and nature of failure were recorded. Results The all-suture anchors placed in the cuff footprint using a transosseous technique displayed superior biomechanical properties. Sutures sited in this way demonstrated a maximum tensile load to failure of 542 N as well as a highest mean load to failure and the maximum number of cycles before anchor failure. In descending order, all-suture anchors placed in the lateral footprint were significantly superior to those located in the medial row and in a simulated Hill–Sachs defect. Discussion Anchors placed in the rotator cuff footprint exceeded the physiological isometric abduction forces for the supraspinatus and infraspinatus. Data obtained from our study suggest that all-suture anchors are strong enough to be used for the repair of rotator cuff tears.

scholarly journals Simultaneous Treatment with Statins and Aspirin Reduces the Risk of Prostate Cancer Detection and Tumorigenic Properties in Prostate Cancer Cell Lines

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
M. Olivan ◽  
M. Rigau ◽  
E. Colás ◽  
M. Garcia ◽  
M. Montes ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Cell Lines ◽  
Lipid Lowering ◽  
Concomitant Treatment ◽  
Simultaneous Treatment ◽  
Invasion And Migration ◽  
Beneficial Effects ◽  
Increased Risk ◽  
And Migration

Nowadays prostate cancer is the most common solid tumor in men from industrialized countries and the second leading cause of death. At the ages when PCa is usually diagnosed, mortality related to cardiovascular morbidity is high; therefore, men at risk for PCa frequently receive chronic lipid-lowering and antiplatelet treatment. The aim of this study was to analyze how chronic treatment with statins, aspirin, and their combination influenced the risk of PCa detection. The tumorigenic properties of these treatments were evaluated by proliferation, colony formation, invasion, and migration assays using different PCa cell lines, in order to assess how these treatments act at molecular level. The results showed that a combination of statins and aspirin enhances the effect of individual treatments and seems to reduce the risk of PCa detection (OR: 0.616 (95% CI: 0.467–0.812),P<0.001). However, if treatments are maintained, aspirin (OR: 1.835 (95% CI: 1.068–3.155),P=0.028) or the combination of both drugs (OR: 3.059 (95% CI: 1.894–4.939),P<0.001) represents an increased risk of HGPCa. As observed at clinical level, these beneficial effectsin vitroare enhanced when both treatments are administered simultaneously, suggesting that chronic, concomitant treatment with statins and aspirin has a protective effect on PCa incidence.

scholarly journals In vitro Biomechanical Study of Pulvertaft Tendon Weaving Technique

2011 ◽  
Vol 15 (2) ◽  
pp. 62-64 ◽  
Author(s):  
Yuen Chi-Pan ◽  
Yen Chi-Hung ◽  
Leung Hon-Bong ◽  
Tse Wing-Lim ◽  
Ho Pak-Cheong ◽  
...  
Keyword(s):  
Peak Load ◽  
Tendon Repair ◽  
Early Mobilization ◽  
Biomechanical Properties ◽  
Biomechanical Study ◽  
Load To Failure ◽  
Active Mobilization ◽  
Passive Mobilization ◽  
Single Suture

Background/Purposes The outcome of tendon repair depends on the strength, which allows early active mobilization to achieve better function without rupture. The aims of this study are to assess quantitatively the biomechanical properties and relationship between the number of tendon weaving and suture method using Pulvertaft technique. Results We found that the load to failure was increased with increasing number of weaves and sutures. From 1-weave to 4-weave single suture samples, the peak load to failure was 9.5 N, 19.7 N, 37.5 N, and 42.6 N, respectively. Based on previous studies, wrist and finger tendons should withstand 1–8N on passive mobilization. Conclusion On active mobilization, finger tendon repair need to provide 34 N for immediate mobilization. Therefore, irrespective of number of sutures, both 3- and 4-weave repairs could allow early mobilization biomechanically.

Comparison of double locking plate constructs with single non-locking plate constructs in single cycle to failure in bending and torsion

2015 ◽  
Vol 28 (04) ◽  
pp. 234-239 ◽  
Author(s):  
K. D. Hutcheson ◽  
S. E. Elder ◽  
J. R. Butler
Keyword(s):  
Locking Plate ◽  
Bending Strength ◽  
Mechanical Performance ◽  
Dynamic Compression ◽  
Biomechanical Properties ◽  
Torsional Stiffness ◽  
Single Cycle ◽  
Torsional Testing ◽  
Bending Loads

SummaryObjective: To evaluate the biomechanical properties of single 3.5 mm broad dynamic compression plate (DCP) and double 3.5 mm String-of-Pearls (SOP) plate constructs in single-cycle bending and torsion. We hypothesized that the double SOP construct would outperform the broad DCP in both bending and torsional testing.Methods: Broad DCP plates and double 3.5 mm SOP plates were secured to a previously validated bone model in an effort to simulate bridging osteosynthesis. Constructs were tested in both four-point bending and torsional testing.Results: The double SOP constructs had significantly greater bending stiffness, bending strength, bending structural stiffness, and torsional stiffness when compared to the broad DCP constructs. The single broad DCP constructs had significantly higher yield torque and yield angles during torsional testing.Clinical relevance: Although the in vitro mechanical performance of the double SOP construct was significantly greater than the single broad DCP constructs under bending loads, the actual differences were small. Various patient, fracture, and implant factors must be considered when choosing an appropriate implant for fracture fixation.

scholarly journals Insulin Therapy and Cancer in Type 2 Diabetes

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Edoardo Mannucci
Keyword(s):  
Type 2 Diabetes ◽  
Insulin Therapy ◽  
Human Insulin ◽  
Epidemiological Studies ◽  
Insulin Analogues ◽  
Negative Effects ◽  
Beneficial Effects ◽  
Increased Risk

Despite the availability of many other agents, insulin is widely used as a treatment for type 2 diabetes. In vitro, insulin stimulates the growth of cancer cells, through the interaction with insulin-like growth factor-1 (IGF-1) receptors and its own receptors. In observational surveys on type 2 diabetes, insulin therapy is associated with an increased incidence of several forms of cancer, although it is difficult to discriminate the effect of confounders from that of insulin itself. Randomized trials do not confirm the increased risk associated with insulin therapy, although they do not allow to rule out some negative effects on specific forms of cancer, at least at higher doses. Among insulin analogues, glargine has a higher affinity for the IGF-1 receptor and a greater mitogenic potency in vitro than human insulin, but it is extensively metabolized in vitro to products with low IGF-1 receptor affinity. Overall, epidemiological studies suggest a possible increase of risk with glargine, with respect to human insulin, only at high doses and for some forms of cancer (i.e., breast). Data from clinical trials do not confirm, but are still insufficient to totally exclude, such increased risk. However, beneficial effects of insulin outweigh potential cancer risks.

The biomechanics of combined lateral and posterior plates for treating proximal humerus fractures with medial column defects

2020 ◽  
Author(s):  
Xuedong Zhang ◽  
YueChao Dou ◽  
Xuefei Wang ◽  
Jianxiong Ma ◽  
Bin Lu ◽  
...  
Keyword(s):  
Locking Plate ◽  
Proximal Humerus ◽  
Three Dimensional ◽  
Biomechanical Properties ◽  
Proximal Humerus Fractures ◽  
Dimensional Finite Element ◽  
Philos Plate ◽  
Humerus Fractures ◽  
Three Dimensional Finite Element

Abstract Background. We investigated the therapeutic effects associated with the combined use of lateral and posterior plates for treating complex proximal humerus fractures. Methods. We used in vitro biomechanical experiments and computer three-dimensional finite element analyses to investigate the biomechanical properties of combined lateral and posterior plates when treating proximal humerus fractures. Eighteen left SAWBONE (Pacific Research Labs) humerus bones were randomly divided among three groups. We established a medial column defect model for surgical neck fractures in each bone specimen and achieved fixation using a proximal humerus locking plate. Each of the three groups used a different fixation method. Group A used a Proximal Humerus Internal Locking System (PHILOS) plate support only. Group B used the PHILOS plate with a posterior locking plate (but without medial column support screws). Group C used the PHILOS plate with both the posterior locking plate and medial column support screws. We subjected three sets of specimens to axial compression, torsion, shear compression, model failure, fatigue testing, and micro-strain analyses. Results and conclusions. In vitro biomechanical analysis and three-dimensional finite element analyses showed that the PHILOS plate, in combination with the posterior locking plate and medial column support screws (Group C), had significantly enhanced biomechanical properties when compared with traditional single plate supports.

The Comparative Strengths of Orthopaedic Staples Versus a 2.7 mm T Plate in the Stabilisation of Distal Radial Osteotomies

1998 ◽  
Vol 11 (02) ◽  
pp. 100-104 ◽  
Author(s):  
R. A. Read ◽  
R. Day ◽  
M. J. Thomson
Keyword(s):  
Cost Effective ◽  
Bending Stiffness ◽  
Bone Plates ◽  
Torsional Stiffness ◽  
Effective Alternative ◽  
Load To Failure ◽  
Cost Effective Alternative

SummaryDistal radial osteotomies were performed in 20 limbs from ten cadaver specimens. Ten bones were stabilised with two × 1.6 mm surgical bone staples and ten were stabilised with a 2.7 mm T platea. The radii were removed and the osteotomies were biomechanically tested in torsion initially, and then to failure in bending. Statistically significant differences were not found between the two types of repair in torsional stiffness, bending stiffness, deflection to failure in bending, or load to failure in bending. Orthopaedic staples are a simple, cost-effective alternative to bone plates for stabilisation of distal radial osteotomies.Bilateral distal radial osteotomies were created in dog cadavers and then repaired with either two bone staples or a 2.7 mm T plate. The limbs were then tested in vitro to compare the relative strengths of the repairs in torsion and bending. Statistically significant differences were not found between the two methods of stabilisation.

scholarly journals Biomechanical, Biochemical, and Cell Biological Evaluation of Different Collagen Scaffolds for Tendon Augmentation

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Carolin Gabler ◽  
Juliane Spohn ◽  
Thomas Tischer ◽  
Rainer Bader
Keyword(s):  
Biomechanical Testing ◽  
Cell Activity ◽  
Collagen Scaffold ◽  
Biomechanical Properties ◽  
Enzymatic Digestion ◽  
Biological Evaluation ◽  
Collagen Scaffolds ◽  
Beneficial Effects ◽  
Bovine Collagen

Tendon augmentation is increasingly clinically relevant due to rising amount of tendon ruptures because of the aging and more demanding population. Therefore, newly developed scaffolds based on bovine epoxide stabilized collagen maintaining the native fibril-like collagen structure were characterized and compared to two commercially available porcine collagen scaffolds. For biomechanical testing (ultimate load, ultimate stress, stiffness, and elastic modulus), bovine collagen scaffolds were hydrated and compared to reference products. Cell viability and proliferation were assessed by seeding human primary fibroblasts on each collagen-based scaffold and cultured over various time periods (3 d, 7 d, and 14 d). Live/dead staining was performed and metabolic cell activity (WST-1 assay) was measured. Biochemical degradability was investigated by enzymatic digestion. The bovine collagen scaffold showed significantly enhanced biomechanical properties. These persisted over different rehydration times. Cell biological tests revealed that the bovine collagen scaffolds support reproducible cell colonization and a significant increase in the number of viable cells during cultivation. The results are comparable with the viability and proliferation rate of cells grown on porcine reference materials. With regard to biochemical degradability, all tested materials showed comparable resistance to enzymatic degradation in vitro. Due to imitating the natural tendon structure the new scaffold material is supposed to provide beneficial effects in future clinical application.

An in vitro mechanical comparison of tibial plateau levelling osteotomy plates

2009 ◽  
Vol 22 (06) ◽  
pp. 467-472 ◽  
Author(s):  
D. Coker ◽  
M. Payton ◽  
M. Rochat ◽  
J. Bordelon
Keyword(s):  
Tibial Plateau ◽  
Compressive Loading ◽  
Axial Loading ◽  
Cyclic Fatigue ◽  
Fatigue Properties ◽  
Materials Testing ◽  
Low Profile ◽  
Plate Design ◽  
Load To Failure

SummaryAn in vitro mechanical study was performed to compare the fatigue properties and the loads to failure of four plate designs that are used to stabilise the tibial plateau levelling osteotomy (TPLO). Seventy-two gapped osteotomy models were created using 3.5 mm versions of the following plates: a standard TPLO plate, a low profile TPLO plate, a locking TPLO plate (LocP), and a broad locking TPLO plate (bLocP). The 18 constructs for each plate design were sub-divided into three identical groups of six. Six constructs were mounted in a materials testing device and subjected to cyclic compressive loading until failure was observed or one-million cycles were achieved. Additionally, six constructs of each plate design were tested in compressive axial loading and six others in four-point bending in a load-to-failure manner. To provide residual strength comparisons, the six constructs undergoing cyclic fatigue compression testing were also tested in axial compressive loading. There were not any significant differences in stiffness between plates tested in axial compressive loading. However, mean loads at failure were higher for the LocP and bLocP constructs. The bLocP had a significantly higher mean stiffness and mean load at failure compared to the other constructs tested in fourpoint bending.

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