scholarly journals Biomechanical Strength of Scaphoid Partial Unions

2018 ◽  
Vol 07 (05) ◽  
pp. 399-403 ◽  
Author(s):  
Mark Snoddy ◽  
Donald Lee ◽  
Marc Richard ◽  
Mihir Desai ◽  
Adam Brekke
Keyword(s):  
Failure Mechanism ◽  
Clinical Relevance ◽  
Permanent Deformation ◽  
Maximum Load ◽  
Control Group ◽  
Average Maximum ◽  
Significant Difference ◽  
Load To Failure ◽  
Biomechanical Strength ◽  
Inherent Stability

Background It remains unknown how much force a partially united scaphoid can sustain without refracturing. This is critical in determining when to discontinue immobilization in active individuals. Purpose The purpose of this study was to test the biomechanical strength of simulated partially united scaphoids. We hypothesized that no difference would exist in load-to-failure or failure mechanism in scaphoids with 50% or more bone at the waist versus intact scaphoids. Materials and Methods Forty-one cadaver scaphoids were divided into four groups, three experimental osteotomy groups (25, 50, and 75% of the scaphoid waist) and one control group. Each was subjected to a physiologic cantilever force of 80 to 120 N for 4,000 cycles, followed by load to failure. Permanent deformation during physiologic testing and stiffness, max force, work-to-failure, and failure mechanism during load to failure were recorded. Results All scaphoids survived subfailure conditioning with no significant difference in permanent deformation. Intact scaphoids endured an average maximum load to failure of 334 versus 321, 297, and 342 N for 25, 50, and 75% groups, respectively, with no significant variance. There were no significant differences in stiffness or work to failure between intact, 25, 50, and 75% groups. One specimen from each osteotomy group failed by fracturing through the osteotomy; all others failed near the distal pole loading site. Conclusion All groups behaved similarly under physiologic and load-to-failure testing, suggesting that inherent stability is maintained with at least 25% of the scaphoid waist intact. Clinical Relevance The data provide valuable information regarding partial scaphoid union and supports mobilization once 25% union is achieved.

Biomechanical comparison of two ostectomy configurations for partial mandibulectomy

2017 ◽  
Vol 30 (01) ◽  
pp. 15-19 ◽  
Author(s):  
Brad Matz ◽  
Ramsis Farag ◽  
Harry Boothe ◽  
D. Tillson ◽  
Ralph Henderson ◽  
...  
Keyword(s):  
Stress Concentration ◽  
Clinical Relevance ◽  
Maximum Load ◽  
Mechanical Advantage ◽  
Biomechanical Assessment ◽  
Significant Difference ◽  
Load To Failure ◽  
Distal Aspect ◽  
Biomechanical Comparison ◽  
Alveolar Surface

SummaryObjective: To determine the stiffness and load to failure of two different ostectomy configurations using canine mandibles.Study design: Cadaveric biomechanical assessment.Animals: Paired mandibles (n = 30).Methods: Standardized partial ostectomies were created on the alveolar surface of 30 mandibles. Samples were randomly assigned to right-angled (n = 15) or crescentic ostectomy (n = 15). Excision spanned the mesial aspect of the fourth premolar tooth to the distal aspect of first molar tooth. Mandibles were loaded to failure in three-point ben-ding. The stiffness, displacement at maximum load, and load to failure were measured.Results: There was no significant difference in stiffness (p = 0.59), displacement at maximum load (p = 0.16) and load to failure (p = 0.76) between right-angled or crescentic ostectomy. Right-angled and crescentic ostectomy failed mostly by fracture through an empty alveolus (11/15 and 13/15, respectively).Clinical relevance: No significant differences in load to failure or stiffness between ostectomy techniques were observed. Crescentic ostectomy did not improve the acute load to failure for partial mandibulectomy. The empty alveolus served as a focal stress concentration point eliminating the potential mechanical advantage of a crescentic ostectomy.

Diet-related changes in mechanical properties of rat vertebrae

1992 ◽  
Vol 262 (2) ◽  
pp. R318-R321 ◽  
Author(s):  
G. J. Salem ◽  
R. F. Zernicke ◽  
R. J. Barnard
Keyword(s):  
Mechanical Properties ◽  
Vertebral Body ◽  
Calcium Metabolism ◽  
Bone Mineralization ◽  
Maximum Load ◽  
Control Group ◽  
Buffer Solution ◽  
Cross Sectional ◽  
Lumbar Vertebral Body ◽  
Significant Difference

High fat and sucrose (HFS) diets may induce glucose intolerance, alter calcium metabolism, and lead to deficits in bone mineralization, development, and mechanical properties. To determine the mechanical and structural consequences of a HFS diet on rapidly growing vertebrae, female Sprague-Dawley rats (8 wk) were assigned randomly (2:1) either to a control group (n = 20) fed a low-fat complex-carbohydrate diet or an experimental group (n = 10) fed a HFS diet for 10-12 wk. The sixth lumbar vertebral body (L6) was isolated from the pedicles, morphological measures were taken, and compression was tested at a fast strain rate, while immersed in a warmed (37 degrees C) isotonic physiological buffer solution. No significant difference in body mass existed between HFS and control groups; nevertheless, HFS L6 cross-sectional areas, lengths, and volumes were significantly smaller than controls. The HFS L6 also had significantly lower mechanical properties, including initial maximum load, energy at initial maximum load, and strain energy density at initial maximum load. Diets high in sucrose and fat content have been associated with changes in calcium metabolism, and the results of the current study suggest that in immature vertebrae, a HFS diet may adversely affect vertebral body mechanical integrity and strength.

scholarly journals Comparing Biomechanical Properties, Repair Times, and Value of Common Core Flexor Tendon Repairs

Hand ◽  
2017 ◽  
Vol 13 (3) ◽  
pp. 313-318 ◽  
Author(s):  
Aakash Chauhan ◽  
Patrick Schimoler ◽  
Mark C. Miller ◽  
Alexander Kharlamov ◽  
Gregory A. Merrell ◽  
...  
Keyword(s):  
Flexor Tendon ◽  
Maximum Load ◽  
Biomechanical Properties ◽  
Barbed Suture ◽  
Load To Failure ◽  
Fresh Frozen ◽  
Post Hoc ◽  
Biomechanical Strength ◽  
Determining Factor

Background: The aim of the study was to compare biomechanical strength, repair times, and repair values for zone II core flexor tendon repairs. Methods: A total of 75 fresh-frozen human cadaveric flexor tendons were harvested from the index through small finger and randomized into one of 5 repair groups: 4-stranded cross-stitch cruciate (4-0 polyester and 4-0 braided suture), 4-stranded double Pennington (2-0 knotless barbed suture), 4-stranded Pennington (4-0 double-stranded braided suture), and 6-stranded modified Lim-Tsai (4-0 looped braided suture). Repairs were measured in situ and their repair times were measured. Tendons were linearly loaded to failure and multiple biomechanical values were measured. The repair value was calculated based on operating room costs, repair times, and suture costs. Analysis of variance (ANOVA) and Tukey post hoc statistical analysis were used to compare repair data. Results: The braided cruciate was the strongest repair ( P > .05) but the slowest ( P > .05), and the 4-stranded Pennington using double-stranded suture was the fastest ( P > .05) to perform. The total repair value was the highest for braided cruciate ( P > .05) compared with all other repairs. Barbed suture did not outperform any repairs in any categories. Conclusions: The braided cruciate was the strongest of the tested flexor tendon repairs. The 2-mm gapping and maximum load to failure for this repair approached similar historical strength of other 6- and 8-stranded repairs. In this study, suture cost was negligible in the overall repair cost and should be not a determining factor in choosing a repair.

scholarly journals Biomechanical Effects of Δ9-Tetrahydrocannabinol (THC) and Cannabidiol (CBD), the Major Constituents of Cannabis, on Tendon to Tendon Healing in a Sprague Dawley Rat Achilles Tendon Surgical Repair Model

2020 ◽  
Vol 8 (7_suppl6) ◽  
pp. 2325967120S0039
Author(s):  
Chris Stauch ◽  
Brittany Ammerman ◽  
Michael Aynardi ◽  
Matthew Garner ◽  
Greg Lewis ◽  
...  
Keyword(s):  
Achilles Tendon ◽  
Surgical Repair ◽  
Subcutaneous Administration ◽  
Tendon Healing ◽  
Tensile Load ◽  
Control Group ◽  
Sprague Dawley ◽  
Control Groups ◽  
Significant Difference ◽  
Load To Failure

Objectives: Use of Cannabis is common amongst athletes and the U.S. population at large. Use of Cannabinoid Oil is being increasingly utilized for a number of different pathologies, injuries, and ailments due to anecdotal evidence of its efficacy. Due to the current United States Opioid crisis, Δ9-Tetrahydrocannabinol (THC) and Cannabidiol (CBD), the two major constituents of cannabis, are currently being evaluated as potential safer alternatives to narcotic pain medicines. The effects of recreational and/or therapeutic THC and CBD on musculoskeletal injury and healing however remain largely unknown. Our purpose was to evaluate the biomechanical effects of THC and CBD on tendon to tendon healing in a Sprague Dawley Achilles Tendon injury and surgical repair model. Methods: 33 Sprague Dawley rats were randomly assigned into control (1 ml/kg/day of vehicle containing 5% Cremaphor, 5% ethanol, and 0.9% saline n=12), THC (3 mg/kg/day n = 12), or CBD (3 mg/kg/day n=9) treatment groups. Surgical transection and repair of the Achilles tendon was performed and all rats began subcutaneous administration of their respective drug treatment the day of surgery and for 4 subsequent days, followed by sacrifice. Load to failure and stiffness were calculated from load displacement data during tensile load testing on a MTS machine. One-way ANOVA with heterogeneous variance was utilized for evaluation. Means and 95% confidence intervals were also determined. Results: The CBD group demonstrated the highest mean load to failure of 17.5 N (15.1-19.8 N), with the THC group having the second highest mean load to failure at 17.3 N (15.3-19.2 N), and the control group reporting the lowest at 15.2 N (12.1-18.3 N). No statistical difference was observed between CBD/control (p = 0.25), THC/control (p = 0.29), or CBD/THC groups (p = 0.92, Figure 1A). The THC group reported the highest mean stiffness of 3.9 N/mm (2.7-5.1 N/mm). The CBD and control groups demonstrated mean stiffness values of 3.5 N/mm (2.9-4.1 N/mm) and 3.5 N (2.7-4.3 N/mm), respectively. No statistically significant differences were observed between THC/control (p = 0.51), THC/CBD (p = 0.50), or CBD/control groups (p = 0.96) for stiffness (Figure 1B). Conclusion: Our investigation demonstrates that subcutaneous administration of CBD resulted in the highest mean load to failure while THC administration resulted in the highest mean stiffness of the three groups. This did not result however in a statistically significant difference between groups. In our small animal tendon-to-tendon repair model, use of THC or CBD did not result in decreased biomechanical characteristics, and there was a trend toward improved ultimate strength and stiffness as compared to control. Further evaluation with larger numbers of animals, and evaluating the potential synergistic effects of THC and CBD administered together are warranted. [Figure: see text]

scholarly journals Effect of sodium fluoride in chlorhexidine mouthwashes on force decay and permanent deformation of orthodontic elastomeric chain

2021 ◽  
Vol 33 (1) ◽  
pp. 74
Author(s):  
Erliera Sufarnap ◽  
Kholidina Imanda Harahap ◽  
Terry Terry
Keyword(s):  
Sodium Fluoride ◽  
Artificial Saliva ◽  
Permanent Deformation ◽  
Control Group ◽  
P Value ◽  
Control Group Design ◽  
Force Decay ◽  
Significant Difference ◽  
Group 2 ◽  
Elastomeric Chains

Introduction: Orthodontic elastomeric chain is polyurethane elastomer that is widely used among orthodontists due to its functions. Chlorhexidine (CHX) and sodium fluoride (NaF) are listed in mouthwash composition which could affect the mechanical properties of the elastomeric chain. This study was aimed to analyze the effect of sodium fluoride in chlorhexidine mouthwashes on force decay and permanent deformation of orthodontic elastomeric chains. Methods: This research is an experimental analytic laboratory with pretest-posttest control group design. 150 samples of orthodontic chains were divided into three groups. Group 1: artificial saliva (control group); Group 2: 0,1% chlorhexidine gluconate solution (CHX); Group 3: 0,1% chlorhexidine digluconate with sodium fluoride solution (CHX-NaF). The orthodontic elastomeric chain was stretched and maintained at a standardized distance equivalent to a force of 300 g. The measurement of force decay and permanent deformation were performed with digital force gauge and digital caliper (0.01mm) at intervals of the first, seventh, fourteenth, twenty-first, and twenty-eighth days, respectively. Results: The force decay and permanent deformation of the elastomeric chain compared between three groups (control, CHX mouthwash and CHX+NaF mouthwash) showed did not have any significantly different (p-value>0,05) at the first, seventh, fourteenth, twenty-first, and twenty-eighth days, respectively. Conclusion: Sodium fluoride in chlorhexidine mouthwash showing no significant difference among saliva, CHX mouthwash and CHX+NaF mouthwash on force decay and permanent deformation of elastomeric chain.

Biomechanical Comparison of 2 Common Techniques of Minimally Invasive Hallux Valgus Correction

2020 ◽  
pp. 107110072095902
Author(s):  
Amiethab Aiyer ◽  
Dustin H. Massel ◽  
Noman Siddiqui ◽  
Jorge I. Acevedo
Keyword(s):  
Minimally Invasive ◽  
Hallux Valgus ◽  
Ultimate Load ◽  
Biomechanical Testing ◽  
Osteotomy Site ◽  
Yield Load ◽  
Chevron Osteotomy ◽  
Significant Difference ◽  
Load To Failure ◽  
Biomechanical Strength

Background: Hallux valgus is one of the most common surgically corrected forefoot deformities. Compared to open procedures, minimally invasive (MIS) treatment of hallux valgus has resulted in decreased operative time, reduced complication rates, and greater patient satisfaction. Historically, distal chevron osteotomies are the standard for moderate hallux valgus correction. To our knowledge, no studies have evaluated biomechanical strength of transverse and chevron distal first metatarsal osteotomy (DMO) constructs. The purpose of this study was to evaluate the biomechanical strength of these techniques. Methods: Eighteen cadaveric specimens (9 matched pairs) were randomized to transverse or chevron DMO. Each technique was performed by a separate fellowship-trained orthopedic foot and ankle surgeon. Radiographic images were analyzed. Biomechanical testing was performed using Instron Mechanical System. Ultimate load to failure, yield load, and stiffness were assessed. A 10-N preload was applied to the sesamoid bones for stability. A coaxial compression rate (10 mm/min) was applied until failure was observed. Mean and standard deviations were compared. All cadaveric specimens were male. Results: There was no significant difference in percent metadiaphyseal shift between osteotomies ( P = .453). The most common mode of failure was fracture at screw insertion site (55.6%), followed by failure at osteotomy site (44.4%). A trend toward increased ultimate load to failure ( P = .480), yield load ( P = .054), and stiffness ( P = .438) among transverse compared to chevron osteotomy was observed, but this difference was not statistically significant. Conclusion: Biomechanical testing demonstrated no significant difference in ultimate load, yield load, and stiffness between MIS transverse and chevron osteotomy constructs; a trend toward increased strength in the transverse osteotomy cohort was observed. Chevron osteotomies may result in early failure by relative ease of cutout through cancellous bone compared to transverse osteotomies in which failure requires cortical cutout. Clinical Relevance: Use of MIS techniques for hallux valgus correction is gaining clinical traction. Although various clinical studies have evaluated outcomes of these MIS techniques, biomechanical studies have been minimal. Specifically, the potential biomechanical benefits of various MIS hallux valgus osteotomy techniques have not been delineated to date. The content of this manuscript is quite timely, given the rise in use of these MIS techniques.

scholarly journals Comparing the effects of manual and ultrasonic instrumentation on root surface mechanical properties

2016 ◽  
Vol 10 (04) ◽  
pp. 517-521 ◽  
Author(s):  
Muhammad Sohail Zafar
Keyword(s):  
Mechanical Properties ◽  
Surface Roughness ◽  
Study Groups ◽  
Control Group ◽  
Maximum Height ◽  
Root Planing ◽  
Average Maximum ◽  
Significant Difference ◽  
Group 2 ◽  
Group 1

ABSTRACT Objective: The aim of the current study is to analyze the surface profiles of healthy and periodontal-treated roots. In addition, manual and ultrasonic instrumentation methods have been compared in terms of surface mechanical properties of root surfaces including surface roughness, hardness, and elastic modulus. Materials and Methods: This study was conducted using extracted teeth that were randomly divided into two study groups (1 and 2). Root planing was performed using either Gracey curettes (Group 1) or ultrasonic scaler (Group 2). The noncontact profilometer was used to analyze surface roughness before and after root planing. A nanoindenter was used to analyze the surface mechanical properties. Results: The root planing treatment reduced the peak and valley heights hence decreasing the surface roughness. The average maximum height of peaks (Sp) and average maximum height of valleys (Sv) for control groups remain 83.08 ± 18.47 μm and 117.58 ± 18.02 μm. The Sp was reduced to 32.86 ± 7.99 μm and 62.11 ± 16.07 μm for Groups 1 and 2, respectively. The Sv was reduced to 49.32 ± 29.51 μm for Group 1 and 80.87 ± 17.99 μm Group 2. The nanohardness and modulus of elasticity for cementum of the control group remain 0.28 ± 0.13 GPa and 5.09 ± 2.67 GPa, respectively. Conclusions: Gracey curettes and ultrasonic scalers are capable of significantly reducing the roughness following root planing. Although Gracey curettes produced smoother surfaces than ultrasonic scalers, there was no significant difference.

scholarly journals The effect of erythropoietin on rat rotator cuff repair model: An experimental study

2019 ◽  
Vol 27 (2) ◽  
pp. 230949901985638
Author(s):  
Ahmet Oztermeli ◽  
Sinan Karaca ◽  
Istemi Yucel ◽  
Ahmet Midi ◽  
Elif Itir Sen ◽  
...  
Keyword(s):  
Rotator Cuff ◽  
Histological Analysis ◽  
Local Group ◽  
Biomechanical Testing ◽  
Maximum Load ◽  
Control Group ◽  
Load To Failure ◽  
Late Control ◽  
Cuff Repair ◽  
Positive Effect

Objectives:The aim of this study was to determine whether erythropoietin (EPO) can enhance rotator cuff healing in rats as measured by histological analysis and biomechanical testing.Methods:A total of 72 rats were included in this study. In the control group ( n = 24), repair was performed without EPO injection. In the local group ( n = 24) EPO was injected in the repair site. In the systemic group ( n = 24) EPO was administered as an intraperitoneal injection every day for 10 days after repair. Rats were euthanized on day 10 ( n = 12 from each group) and day 28 ( n = 12 from each group). Histopathological ( n = 6) and biomechanical examinations ( n = 6) were done.Results:Biomechanical results reveal that the maximum load to failure values of the early control group were statistically lower than those of the early systemic group ( p = 0.006). Comparing the the total Bonar values histopathologically reveal that the early systemic group was statistically higher than those of the early local group ( p = 0.043). The late control group was statistically higher than those of the late local group ( p = 0.003) and the late systemic group ( p = 0.034). The late systemic group was statistically higher than those of the late local group ( p = 0.003).Conclusions:EPO application had a positive effect biomechanically in the early euthanized group and histopathologically in the late euthanized group.

scholarly journals Arthroscopic versus Open MTP Arthrodesis

2017 ◽  
Vol 2 (3) ◽  
pp. 2473011417S0002 ◽  
Author(s):  
Kenneth Hunt ◽  
Alastair Younger ◽  
Richard Fuld ◽  
Judas Kelley ◽  
Nicholas Anderson ◽  
...  
Keyword(s):  
Cyclic Loading ◽  
Matched Pair ◽  
Preparation Technique ◽  
Locked Plate ◽  
Plate Group ◽  
Low Profile ◽  
Significant Difference ◽  
Load To Failure ◽  
New Generation ◽  
Biomechanical Strength

Category: Midfoot/Forefoot Introduction/Purpose: Hallux metatarsophalangeal (MTP) arthrodesis is a common procedure for painful conditions of the great toe. Dorsal plate fixation for MTP arthrodesis using locked plates produces good clinical outcomes and superior biomechanical strength to other techniques. However, arthroscopic fusion with new generation full thread compression screws is emerging as an alternative to open fusion. This method has been utilized clinically with good outcomes, but the biomechanical strength of arthroscopic MTP fusion fixation techniques is unknown. The purpose of this study was to compare low profile contoured locked plates to new generation full thread compression screws for first MTP fusion, in a biomechanical cadaver model. We hypothesize that there will be no significant difference in plantar gapping during cyclic loading, stiffness, or load-to-failure between the two groups, Methods: The first rays of eight matched pairs of fresh frozen cadaveric feet underwent dissection and DEXA scanning to measure bone mineral density (BMD). The “plate” group was prepared with cup-and-cone reamers, and fixation of the MTP joint with one compression screw and low profile dorsal locked plate. The matched pair “screws” group was prepared through a simulated arthroscopic technique, achieving fixation with two new generation full-thread compression screws, while preserving capsular attachments. Each specimen was loaded on the proximal phalanx in a cantilever fashion to 90 N at 3 Hz for a total of 250,000 cycles. Plantar MTP gap was recorded using a calibrated extensometer; Load-to-failure testing was performed for all specimens that endured cyclical loading; and stiffness was calculated from the final load-to-failure. Data was analyzed with a Student’s T-Test, with significance set at p<.05. Pearson Correlation coefficient (r) was calculated for stiffness and load-to-failure vs. BMD. Results: The plate group demonstrated significantly more plantar gapping during cyclic loading. There was no significant difference in stiffness, 31.6 N/mm (plates) and 51.7 N/mm (screws) (p=0.24) or load-to-failure, 198.6 N (plates) and 290.1 N (screws) (p =.07). Two of 8 screws-only specimens, and 3 of 8 locked plate specimens failed during cyclic loading. These early failures, and stiffness and load-to-failure were highly correlated to BMD for plates (r=0.85 and r=0.62, respectively) and screws only (r=0.82 and r=0.94, respectively). Maximum metatarsal head width measured on lateral view was strongly correlated with load-to-failure and stiffness for both groups (r > 0.7). Conclusion: Arthroscopic hallux MTP arthrodesis utilizing full thread compression screws has similar mean stiffness and load-to- failure compared to a low-profile locking plate, with significantly less plantar gapping. These data, combined with advantages of the arthroscopic preparation technique, support an increased role of arthroscopic fusion in lieu of more invasive open plating techniques. The two preload failures of the screws-only cohort occurred in specimens with the lowest BMD, potentially indicating a clinical contraindication with this technique. BMD and metatarsal width may aid in predicting early failure such that appropriate fixation construct and more conservative post-operative protocols might improve results for these patients.

Improved Healing of Rabbit Patellar Tendon Defects After an Atelocollagen Injection

2021 ◽  
pp. 036354652110305
Author(s):  
Duck Kyu Kim ◽  
Jiyong Ahn ◽  
Seon Ae Kim ◽  
Eun Jeong Go ◽  
Dong Hwan Lee ◽  
...  
Keyword(s):  
Patellar Tendon ◽  
Statistical Significance ◽  
Biomechanical Testing ◽  
Patellar Tendinopathy ◽  
Control Group ◽  
Daily Life Activities ◽  
Tendon Defect ◽  
Significant Difference ◽  
Load To Failure ◽  
Experimental Group

Background: Patellar tendinopathy is a common cause of limitations in daily life activities in young and/or active people. The patellar tendon consists of a complex of collagen fibers; therefore, collagen could be used as a scaffold in the treatment of patellar tendinopathy. Purpose: To evaluate the healing capacity of injected atelocollagen as a treatment scaffold for patellar tendon defect and, hence, its potential for the treatment of patellar tendinopathy. Study Design: Controlled laboratory study. Methods: After receiving a full-thickness patellar tendon defect, 24 New Zealand White rabbits were divided into a control group (without treatment) and an experimental group that received an atelocollagen injection into the defect. Six rabbits from each group were subsequently used for either histologic scoring or biomechanical testing. The Mann-Whitney U test was used to compare histologic evaluation scores and load to failure between the 2 groups. Statistical significance was set at P < .05. Results: The experimental group showed excellent repair of the damaged patellar tendon and good remodeling of the defective area. In contrast, the control group showed defective healing with loose, irregular matrix fibers and adipose tissue formation. A statistically significant difference was found between the 2 groups in both histologic scores and biomechanical tests at postoperative week 12. Conclusion: Injection of atelocollagen significantly improved the regeneration of damaged patellar tendons. Clinical Relevance: Atelocollagen gel injections could be used to treat patellar tendinopathy in outpatient clinic settings.

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