scholarly journals Biomechanical stability of complex coronal plane fracture fixation of the capitellum

2021 ◽  
Author(s):  
Paul Borbas ◽  
Rafael Loucas ◽  
Marios Loucas ◽  
Maximilian Vetter ◽  
Simon Hofstede ◽  
...  
Keyword(s):  
Fracture Fixation ◽  
Ultimate Load ◽  
Locking Plate ◽  
Distal Humerus ◽  
Coronal Plane ◽  
Fixation Strength ◽  
Biomechanical Stability ◽  
Significant Difference ◽  
Load To Failure ◽  
Headless Compression Screws

Abstract Introduction Coronal plane fractures of the distal humerus are relatively rare and can be challenging to treat due to their complexity and intra-articular nature. There is no gold standard for surgical management of these complex fractures. The purpose of this study was to compare the biomechanical stability and strength of two different internal fixation techniques for complex coronal plane fractures of the capitellum with posterior comminution. Materials and methods Fourteen fresh frozen, age- and gender-matched cadaveric elbows were 3D-navigated osteotomized simulating a Dubberley type IIB fracture. Specimens were randomized into one of two treatment groups and stabilized with an anterior antiglide plate with additional anteroposterior cannulated headless compression screws (group antiGP + HCS) or a posterolateral distal humerus locking plate with lateral extension (group PLP). Cyclic testing was performed with 75 N over 2000 cycles and ultimately until construct failure. Data were analyzed for displacement, construct stiffness, and ultimate load to failure. Results There was no significant difference in displacement during 2000 cycles (p = 0.291), stiffness (310 vs. 347 N/mm; p = 0.612) or ultimate load to failure (649 ± 351 vs. 887 ± 187 N; p = 0.140) between the two groups. Conclusions Posterolateral distal humerus locking plate achieves equal biomechanical fixation strength as an anterior antiglide plate with additional anteroposterior cannulated headless compression screws for fracture fixation of complex coronal plane fractures of the capitellum. These results support the use of a posterolateral distal humerus locking plate considering the clinical advantages of less invasive surgery and extraarticular metalware. Level of evidence Biomechanical study.

Comparison of Locking Plate with Interfragmentary Screw Versus Plantarly Applied Anatomic Locking Plate for Lapidus Arthrodesis: A Biomechanical Cadaveric Study

2016 ◽  
Vol 10 (3) ◽  
pp. 227-231 ◽  
Author(s):  
James M. Cottom ◽  
Joseph S. Baker
Keyword(s):  
Ultimate Load ◽  
Locking Plate ◽  
Statistical Significance ◽  
Biomechanical Study ◽  
Clinical Settings ◽  
First Metatarsal ◽  
Low Profile ◽  
Significant Difference ◽  
Load To Failure ◽  
Anatomic Locking Plate

Arthrodesis of the first metatarsal cuneiform joint, or Lapidus procedure, is a widely accepted treatment for hallux valgus. Recent studies have focused on comparing various constructs for this procedure both in the laboratory and clinical settings. The current study compared in a cadaveric model the strength of 2 constructs. The first construct utilized a medially applied low-profile locking plate and an interfragmentary screw directed from plantar-distal to dorsal-proximal. The second construct consisted of a plantarly applied plate with a compression screw placed through the plate from plantar-distal to dorsal-proximal. The ultimate load to failure for the 2 groups tested was 255.38 ± 155.38 N and 197.48 ± 108.61 N, respectively (P = .402). There was no significant difference found between the 2 groups with respect to ultimate load to failure, stiffness of the construct, or moment at time of failure. In conclusion, the medially applied plate with plantar interfragmentary screw appears to be stronger than the plantar Lapidus plate tested for first metatarsal cuneiform arthrodesis, though this difference did not reach statistical significance. Levels of Evidence: Level V: Biomechanical Study

Single Versus Dual Headless Compression Screw Fixation of Scaphoid Nonunions: A Biomechanical Comparison

Hand ◽  
2021 ◽  
pp. 155894472097411
Author(s):  
Luke T. Nicholson ◽  
Kristen M. Sochol ◽  
Ali Azad ◽  
Ram Kiran Alluri ◽  
J. Ryan Hill ◽  
...  
Keyword(s):  
Screw Fixation ◽  
Qualitative Assessment ◽  
Secondary Outcome ◽  
Scaphoid Nonunion ◽  
Compression Screw ◽  
Single Screw ◽  
Headless Compression Screw ◽  
Significant Difference ◽  
Load To Failure ◽  
Headless Compression Screws

Background: Management of scaphoid nonunions with bone loss varies substantially. Commonly, internal fixation consists of a single headless compression screw. Recently, some authors have reported on the theoretical benefits of dual-screw fixation. We hypothesized that using 2 headless compression screws would impart improved stiffness over a single-screw construct. Methods: Using a cadaveric model, we compared biomechanical characteristics of a single tapered 3.5- to 3.6-mm headless compression screw with 2 tapered 2.5- to 2.8-mm headless compression screws in a scaphoid waist nonunion model. The primary outcome measurement was construct stiffness. Secondary outcome measurements included load at 1 and 2 mm of displacement, load to failure for each specimen, and qualitative assessment of mode of failure. Results: Stiffness during load to failure was not significantly different between single- and double-screw configurations ( P = .8). Load to failure demonstrated no statistically significant difference between single- and double-screw configurations. Using a qualitative assessment, the double-screw construct maintained rotational stability more than the single-screw construct ( P = .029). Conclusions: Single- and double-screw fixation constructs in a cadaveric scaphoid nonunion model demonstrate similar construct stiffness, load to failure, and load to 1- and 2-mm displacement. Modes of failure may differ between constructs and represent an area for further study. The theoretical benefit of dual-screw fixation should be weighed against the morphologic limitations to placing 2 screws in a scaphoid nonunion.

scholarly journals Metacarpal shaft fixation: a biomechanical comparison of dorsal plating, lag screws, and headless compression screws

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Felix G. E. Dyrna ◽  
Daniel M. Avery ◽  
Ryu Yoshida ◽  
David Lam ◽  
Simon Oeckenpöhler ◽  
...  
Keyword(s):  
Peak Load ◽  
Rigid Fixation ◽  
Advantages And Disadvantages ◽  
Shaft Fractures ◽  
Metacarpal Shaft ◽  
Significant Difference ◽  
Load To Failure ◽  
Headless Compression Screws ◽  
Diaphyseal Fractures ◽  
Dorsal Plating

Abstract Background Metacarpal shaft fractures are common and can be treated nonoperatively. Shortening, angulation, and rotational deformity are indications for surgical treatment. Various forms of treatment with advantages and disadvantages have been documented. The purpose of the study was to determine the stability of fracture fixation with intramedullary headless compression screws in two types of metacarpal shaft fractures and compare them to other common forms of rigid fixation: dorsal plating and lag screw fixation. It was hypothesized that headless compression screws would demonstrate a biomechanical stronger construct. Methods Five matched paired hands (age 60.9 ± 4.6 years), utilizing non-thumb metacarpals, were used for comparative fixation in two fracture types created by an osteotomy. In transverse diaphyseal fractures, fixation by headless compression screws (n = 7) and plating (n = 8) were compared. In long oblique diaphyseal fractures, headless compression screws (n = 8) were compared with plating (n = 8) and lag screws (n = 7). Testing was performed using an MTS frame producing an apex dorsal, three point bending force. Peak load to failure and stiffness were calculated from the load-displacement curve generated. Results For transverse fractures, headless compression screws had a significantly higher stiffness and peak load to failure, means 249.4 N/mm and 584.8 N, than plates, means 129.02 N/mm and 303.9 N (both p < 0.001). For long oblique fractures, stiffness and peak load to failure for headless compression screws were means 209 N/mm and 758.4 N, for plates 258.7 N/mm and 518.5 N, and for lag screws 172.18 N/mm and 234.11 N. There was significance in peak load to failure for headless compression screws vs plates (p = 0.023), headless compression screws vs lag screws (p < 0.001), and plates vs lag screws (p = 0.009). There was no significant difference in stiffness between groups. Conclusion Intramedullary fixation of diaphyseal metacarpal fractures with a headless compression screw provides excellent biomechanical stability. Coupled with lower risks for adverse effects, headless compression screws may be a preferable option for those requiring rapid return to sport or work. Level of evidence Basic Science Study, Biomechanics.

scholarly journals How Many Proximal Screws Are Needed for a Stable Proximal Humerus Fracture Fixation?

2021 ◽  
Vol 12 ◽  
pp. 215145932199274
Author(s):  
Hyojune Kim ◽  
Myung Jin Shin ◽  
Erica Kholinne ◽  
Janghyeon Seo ◽  
Duckwoo Ahn ◽  
...  
Keyword(s):  
Cyclic Loading ◽  
Proximal Humerus Fracture ◽  
Locking Plate ◽  
Proximal Humerus ◽  
Humerus Fracture ◽  
Proximal Fragment ◽  
Maximum Displacement ◽  
Significant Difference ◽  
Load To Failure ◽  
Screw Group

Purpose: This biomechanical study investigates the optimal number of proximal screws for stable fixation of a 2-part proximal humerus fracture model with a locking plate. Methods: Twenty-four proximal humerus fracture models were included in the study. An unstable 2-part fracture was created and fixed by a locking plate. Cyclic loading and load-to-failure tests were used for the following 4 groups based on the number of screws used: 4-screw, 6-screw, 7-screw, and 9-screw groups. Interfragmentary gaps were measured following cyclic loading and compared. Consequently, the load to failure, maximum displacement, stiffness, and mode of failure at failure point were compared. Results: The interfragmentary gaps for the 4-screw, 6-screw, 7-screw, and 9-screw groups were significantly reduced by 0.24 ± 0.09 mm, 0.08 ± 0.06 mm, 0.05 ± 0.01 mm, and 0.03 ± 0.01 mm following 1000 cyclic loading, respectively. The loads to failure were significantly different between the groups with the 7-screw group showing the highest load to failure. The stiffness of the 7-screw group was superior compared with the 6-screw, 9-screw, and 4-screw groups. The maximum displacement before failure showed a significant difference between the comparative groups with the 4-screw group having the lowest value. The 7-screw group had the least structural failure rate (33.3%). Conclusion: At least 7 screws would be optimal for proximal fragment fixation of proximal humerus fractures with medial comminution to minimize secondary varus collapse or fixation failure. Level of Evidence: Basic science study.

Biomechanical Evaluation of Minimally Invasive Repairs for Complete Acromioclavicular Joint Dislocation

2007 ◽  
Vol 35 (6) ◽  
pp. 955-961 ◽  
Author(s):  
Mathias Wellmann ◽  
Thore Zantop ◽  
Andre Weimann ◽  
Michael J. Raschke ◽  
Wolf Petersen
Keyword(s):  
Minimally Invasive ◽  
Ultimate Load ◽  
Suture Anchor ◽  
Biomechanical Properties ◽  
Fixation Strength ◽  
Acromioclavicular Joint Dislocation ◽  
Coracoclavicular Ligament ◽  
Invasive Approach ◽  
Significant Difference ◽  
Permanent Elongation

Background The conventional coracoclavicular ligament augmentation with a single polydioxanone loop has been shown to have some pivotal disadvantages. Hypothesis A minimally invasive flip button/polydioxanone repair provides similar biomechanical properties to the conventional polydioxanone cerclage around the coracoid. However, the authors expected a difference in linear stiffness, ultimate load, and permanent elongation between suture anchor repairs and polydioxanone repairs. Study Design Controlled laboratory study. Methods The tensile fixation strength of 4 different minimally invasive repairs was tested in a porcine metatarsal model: (1) 1.3-mm single polydioxanone cerclage with a subcoracoidal flip button fixation, (2) 1.3-mm single polydioxanone cerclage, (3) Twinfix Ti 3.5-mm/Ultrabraid 2-suture anchor, and (4) Twinfix Ti 5.0-mm/Ultrabraid 2-suture anchor. The testing protocol included cyclic superoinferior loading and a subsequent load to failure trial. Results The flip button repair (646 N) and the conventional polydioxanone banding (663 N) revealed significant higher ultimate loads than did the suture anchor repairs (295 and 331 N, respectively; P < .001), whereas no significant differences were found for the elongation behavior under cyclic loading. Conclusion There was no significant difference between the 2 polydioxanone repairs. The ultimate load of the flip button procedure reaches the level of the native coracoclavicular ligament complex as it has been quantified in the literature. Clinical Relevance Although the biomechanical results comparing a minimally invasive flip button procedure versus a conventional polydioxanone cerclage are similar, the authors recommend the flip button procedure because of its minimally invasive approach and the secure subcoracoidal fixation technique with a minimized risk of anterior loop dislocation and neurovascular damage.

Lack of Surgeon Standardization on Implant Selection in Ankle Fracture Fixation May Increase Costs and Decrease Contribution Margin

2021 ◽  
pp. 193864002110093
Author(s):  
David N. Bernstein ◽  
Philip Hanna ◽  
Nelson Merchan ◽  
Edward K. Rodriguez ◽  
Paul T. Appleton ◽  
...  
Keyword(s):  
Fracture Fixation ◽  
Ankle Fracture ◽  
Locking Plate ◽  
Linear Regression Analysis ◽  
Open Reduction Internal Fixation ◽  
Fracture Type ◽  
Contribution Margin ◽  
Suture Button ◽  
Significant Difference ◽  
Hardware Costs

Background Surgical standardization has been shown to decrease costs without impacting quality; however, there is limited literature on this subject regarding ankle fracture fixation. Methods. Between October 5, 2015 and September 27, 2017, a total of 168 patients with isolated ankle fractures who underwent open reduction, internal fixation (ORIF) were analyzed. Financial data were analyzed across ankle fracture classification type, implant characteristics, and surgeons. Bivariate analyses were conducted. One-way analysis of variance was used to compare hardware costs across all 5 surgeons. Linear regression analysis was used to determine if hardware cost differed by surgeon when accounting for fracture type. Results The mean contribution margin was $4853 (SD $6446). There was a significant difference in implant costs by surgeon (range, lowest-cost surgeon: $471 [SD $283] to $1609 [SD $819]; P < .001). There was no difference in the use of a suture button or locking plate by fracture type (P = .13); however, the cost of the implant was significantly higher if a suture button or locking plate was used ($1014 [SD $666] vs $338 [SD $176]; P < .001). There was an association between surgeon 3 (β = 200.32 [95% CI 6.18-394.47]; P = .043) and surgeon 4 (β = 1131.07 [95% CI 906.84-1355.30]; P < .001) and higher hardware costs. Conclusions Even for the same ankle fracture type, a wide variation in implant costs exists. The lack of standardization among surgeons accounted for a nearly 3.5-fold difference, on average, between the lowest- and highest-cost surgeons, negatively affecting contribution margin. Levels of Evidence Level IV

scholarly journals Braided tape is equivalent to modified Mason-Allen multi-strand #2 suture in subscapularis muscle repair: results of a biomechanical study

2016 ◽  
Vol 9 (2) ◽  
pp. 85-91
Author(s):  
Benjamin Léger-St-Jean ◽  
Jérémie Ménard ◽  
Stéphanie Hinse ◽  
Frédéric Balg ◽  
Dominique M Rouleau
Keyword(s):  
Cyclic Loading ◽  
Ultimate Load ◽  
Tendon Repair ◽  
Biomechanical Study ◽  
Fixation Method ◽  
Subscapularis Tendon ◽  
Mineral Density ◽  
Significant Difference ◽  
Load To Failure ◽  
The Mean

Background To help determine the optimal fixation method for subscapularis tendon repair in arthroplasty, the present study compares single-passage transosseous tape (BT) and modified Mason-Allen #2 suture (MA). Methods Eighteen human cadaveric shoulders were randomized to two repair constructs after arthroplasty preparation. Both techniques included two transosseous passages through the bicipital groove and then through the tendon at the level of the anatomical neck. Construct was tested using a traction machine, measuring cyclic loading and ultimate load to failure. Results The mean age of our specimens was 71 years. No significant difference was observed between the repair techniques in both mean ultimate load and cyclic loading. The mean (SD) ultimate load (UL) for BT was 293 (84) N and 342 (117) N for MA, which was not statistically significant ( p = 0.374). The majority of repairs failed in the tendon. Bone cut-out was observed with the MA but not for the BT repair. No correlation was found between bone density and UL for BT ( r = −0.09) but there was strong correlation for MA ( r = 0.63). Conclusions The MA repair appears to be more dependant on bone mineral density for ultimate load, indicating that braided-tape might be better suited for osteoporotic patients to avoid bone cut-out.

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 Impact of Screw Length on Proximal Scaphoid Fracture Biomechanics

2019 ◽  
Vol 08 (05) ◽  
pp. 360-365 ◽  
Author(s):  
Samik Patel ◽  
Juan Giugale ◽  
Nathan Tiedeken ◽  
Richard E. Debski ◽  
John R. Fowler
Keyword(s):  
Cyclic Loading ◽  
Fracture Fixation ◽  
Ultimate Load ◽  
Scaphoid Fracture ◽  
Fracture Site ◽  
Compression Screw ◽  
Headless Compression Screw ◽  
Scaphoid Fractures ◽  
Screw Length ◽  
Significant Difference

Background Proximal scaphoid fractures display high nonunion rates and increased revision cases. Waist fracture fixation involves maximizing screw length within the cortex; however, the optimal screw length for proximal scaphoid fractures remains unknown. Purpose The main purpose of this article is to compare stiffness and ultimate load for proximal scaphoid fracture fixation of various headless compression screw lengths. Methods Eighteen scaphoids underwent an osteotomy simulating a 7 mm oblique proximal fracture. Screws of three lengths (10, 18, and 24 mm) were randomly assigned for fixation. Each specimen underwent cyclic loading with stiffness calculated during the last loading cycle. Specimens that withstood cyclic loading were loaded to failure. Results No significant difference in stiffness between screw lengths was found. Ultimate load was significantly impacted by the screw length. A significant difference in ultimate load between a 10 and 24 mm screw was found; however, no significant difference occurred in ultimate load between an 18 and 24 mm screw. Conclusions No significant difference in stiffness between all groups could be due to similarities in purchase in the proximal aspect. The 10 mm screw withstanding less ultimate load compared to the 24 mm screw could be due to the 10 mm screw gaining less purchase on either side of the fracture site compared to the 24 mm screw. Lack of significant difference in ultimate load between the 18 and 24 mm screw could be occurring because the fracture site is closer to the 18 mm screw midpoint, as distal threads are engaged closer to the fracture. Clinical Relevance Maximizing screw length may not provide superior fixation biomechanically compared with fixation utilizing a 6 mm shorter screw for proximal scaphoid fractures.

Biomechanical Comparison of Low-Profile Contoured Locking Plate With Single Compression Screw to Fully Threaded Compression Screws for First MTP Fusion

2019 ◽  
Vol 40 (7) ◽  
pp. 836-844
Author(s):  
Richard S. Fuld ◽  
Pam Kumparatana ◽  
Judas Kelley ◽  
Nicholas Anderson ◽  
Todd Baldini ◽  
...  
Keyword(s):  
Locking Plate ◽  
Matched Pair ◽  
Mineral Density ◽  
Compression Screw ◽  
Plate Group ◽  
Low Profile ◽  
Significant Difference ◽  
Load To Failure ◽  
New Generation ◽  
Screw Group

Background: Open metatarsophalangeal (MTP) arthrodesis using locked plates produces good clinical outcomes. However, arthroscopic fusion with new-generation fully threaded compression screws is emerging as an alternative. The purpose of this study was to compare low-profile contoured locked plates with fully threaded compression screws for first MTP fusion, in a biomechanical cadaveric model. Methods: The first rays of 8 matched pairs of fresh frozen cadaveric feet underwent dissection and dual-energy x-ray absorptiometry (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 1 compression screw and low-profile dorsal locked plate. The matched-pair “screws” group was prepared through a simulated arthroscopic technique, achieving fixation with 2 new-generation fully threaded compression screws. The plantar MTP gap was recorded with an extensometer during 250 000 90-N cyclic loads followed by a single load to failure. Results: The screw group demonstrated significantly greater stiffness, 31.6 N/mm (plates) and 51.7 N/mm (screws) ( P = .0045). There was no significant difference in plantar gapping or load to failure, 198.6 N (plates) and 290.1 N (screws) ( P = .2226). Stiffness and load to failure were highly correlated to BMD for the screw group, r =0.79 and r = 0.94, respectively, but less so for the plate group, r = 0.36 and r = 0.62, respectively. The maximum metatarsal head height measured on the lateral view was strongly correlated with load to failure for both the plate- and screw-only groups ( r > 0.9). Conclusion: These data demonstrate that hallux MTP arthrodesis utilizing fully threaded compression screws had similar plantar gapping and load to failure when compared with the low-profile locking plate, but with significantly more stiffness. These results support an increased role of fully threaded screws for MTP arthrodesis using either the arthroscopic or open technique. However, with decreased BMD plate fixation may remain the better fixation choice. Clinical Relevance: Our data suggest that with regard to construct stability, fully threaded headless compression screws may be just as effective as low-profile locking plates, but BMD and MTP joint fluoroscopic measurements should be considered in the decision-making process for fixation.

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