Length of Plates and Number of Screws for the Fixation of Distal Humerus Fractures: A Finite Element Biomechanical Study

Zarifian, Ahmadreza; Fough, Ali Akbarinezhad; Eygendaal, Denise; Rivlin, Michael; Shaegh, Seyed Ali Mousavi; Kachooei, Amir Reza

doi:10.1016/j.jhsa.2021.07.010

Cited by 8 publications

(2 citation statements)

References 27 publications

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“…Screw variables were size, threads, number, distribution, and angle ( Figure 1 ). Outcome metrics for IAFs [ 32 – 58 ] and EAFs [ 16 – 18 , 59 – 80 ] could be fracture motion (i.e., BOC1); bone, plate, or screw stress (i.e., BOC2); bone stress under the plate (i.e., BOC3); and “fatigue life,” defined as the number of loading cycles needed for failure (i.e., BOC4), as well as Os and Fs (Tables 1 , 2 , and 3 ).…”

Section: Resultsmentioning

confidence: 99%

“…For EAFs, a single long curved J-plate had greater bending stiffness as well as more torsional stiffness and strength versus a single straight short plate [ 77 ], but it only had higher stiffness or strength in half the loading modes versus a single wider upside-down proximal humerus plate repurposed for the distal humerus [ 71 ]. Longer versus shorter double plates exhibited less fracture motion [ 80 ], reduced bone and plate stress [ 80 ], and higher stiffness and/or strength in various loading modes [ 64 , 80 ]. A single Y-plate versus double plates with standard shapes in parallel or perpendicular configurations had more fracture motion [ 59 , 75 ], higher bone and plate stress [ 75 ], shorter axial and bending fatigue life [ 65 ], or lower stiffness in most loading modes [ 59 , 65 , 75 ], but one study showed the reverse for fracture motion and stiffness in bending [ 75 ].…”

Section: Resultsmentioning

confidence: 99%

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Biomechanical Design Optimization of Distal Humerus Fracture Plates: A Review

Zdero,

Brzozowski,

Schemitsch

2024

BioMed Research International

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The goal of this article was to review studies on distal humerus fracture plates (DHFPs) to understand the biomechanical influence of systematically changing the plate or screw variables. The problem is that DHFPs are commonly used surgically, although complications can still occur, and it is unclear if implant configurations are always optimized using biomechanical criteria. A systematic search of the PubMed database was conducted to identify English‐language biomechanical optimization studies of DHFPs that parametrically altered plate and/or screw variables to analyze their influence on engineering performance. Intraarticular and extraarticular fracture (EAF) data were separated and organized under commonly used biomechanical outcome metrics. The results identified 52 eligible DHFP studies, which evaluated various plate and screw variables. The most common plate variables evaluated were geometry, hole type, number, and position. Fewer studies assessed screw variables, with number and angle being the most common. However, no studies examined nonmetallic materials for plates or screws, which may be of interest in future research. Also, articles used various combinations of biomechanical outcome metrics, such as interfragmentary fracture motion, bone, plate, or screw stress, number of loading cycles to failure, and overall stiffness (Os) or failure strength (Fs). However, no study evaluated the bone stress under the plate to examine bone “stress shielding,” which may impact bone health clinically. Surgeons treating intraarticular and extraarticular distal humerus fractures should seriously consider two precontoured, long, thick, locked, and parallel plates that are secured by long, thick, and plate‐to‐plate screws that are located at staggered levels along the proximal parts of the plates, as well as an extra transfracture plate screw. Also, research engineers could improve new studies by perusing recommendations in future work (e.g., studying alternative nonmetallic materials or “stress shielding”), clinical ramifications (e.g., benefits of locked plates), and study quality (e.g., experimental validation of computational studies).

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Biomechanical Design Optimization of Distal Humerus Fracture Plates: A Review

Zdero,

Brzozowski,

Schemitsch

2024

BioMed Research International

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Biomechanical design of a new proximal humerus fracture plate using alternative materials

Islam,

Dembowski,

Schemitsch

et al. 2024

Numer Methods Biomed Eng

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Comminuted proximal humerus fractures are often repaired by metal plates, but potentially still experience bone refracture, bone “stress shielding,” screw perforation, delayed healing, and so forth. This “proof of principle” investigation is the initial step towards the design of a new plate using alternative materials to address some of these problems. Finite element modeling was used to create design graphs for bone stress, plate stress, screw stress, and interfragmentary motion via three different fixations (no, 1, or 2 “kickstand” [KS] screws across the fracture) using a wide range of plate elastic moduli (EP = 5–200 GPa). Well‐known design optimization criteria were used that could minimize bone, plate, and screw failure (i.e., peak stress < ultimate tensile strength), reduce bone “stress shielding” (i.e., bone stress under the new plate ≥ bone stress for an intact humerus, titanium plate, and/or steel plate “control”), and encourage callus growth leading to early healing (i.e., 0.2 mm ≤ axial interfragmentary motion ≤ 1 mm; shear/axial interfragmentary motion ratio <1.6). The findings suggest that a potentially optimal configuration involves the new plate being manufactured from a material with an EP of 5–41.5 GPa with 1 KS screw; but, using no KS screws would cause immediate bone fracture and 2 KS screws would almost certainly lead to delayed healing. A prototype plate might be fabricated using alternative materials suggested for orthopedics and other industries, like fiber‐metal laminates, fiber‐reinforced polymers, metal foams, pure polymers, shape memory alloys, or 3D‐printed porous metals.

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