JHS - 2026-04-24 - Journal Article
Biomechanical Analysis of Standard Locking Compression Plate versus Dual Minifragment Locking Plates in Ulna Shaft Fracture Fixation: A Human Cadaveric Study.
Kraus M, van Rossenberg L, Zderic I, Pastor T, Gueorguiev B, Richards RG, Breckwoldt TK, Pape HC, Beeres FJP, Pastor T
Topics
Key Takeaway
Dual minifragment locked plating (2.5 mm + 2.0 mm orthogonal plates) achieves comparable axial, bending, and shear stiffness to a single 3.5 mm LCP for ulna shaft fractures, though angular displacement under cyclic torsional loading was significantly greater (P ≤ .018).
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Summary
This study asked whether dual minifragment locked plating (2.5 mm medial + 2.0 mm posterolateral, orthogonal) provides equivalent biomechanical stability to a single 3.5 mm LCP for ulna shaft fractures, motivated by the ~25% secondary implant removal rate from soft tissue irritation with standard plating. Using a standardized 10-mm gap model in 16 paired cadaveric ulnae, no significant differences were found in axial, torsional, or bending stiffness, nor in shear displacement or cycles to failure. However, dual minifragment constructs showed significantly greater angular displacement under 2,000-cycle torsional loading (P ≤ .018), and all failures occurred at the most distal screw regardless of construct.
Key Limitation
The 10-mm standardized gap model eliminates fracture-pattern variability and does not replicate the rotational forces of forearm pronation-supination in a functional musculotendinous environment, making torsional failure data difficult to extrapolate clinically.
Original Abstract
PURPOSE
The main postoperative complications after fixation of ulna shaft fractures are nonunion and soft tissue irritation. Current standards recommend 3.5 mm locking compression plates, which are prone to cause soft tissue irritation, necessitating secondary implant removal in approximately 25% of cases. Therefore, an alternative approach considering a combination of two minifragment locking plates has been proposed. The aim of this study was to biomechanically compare a single 3.5 mm locking compression plate fixation versus dual minifragment locked plating of ulna shaft fractures in a human cadaveric model.
METHODS
Sixteen paired human cadaveric ulnae with a standardized 10-mm simulated fracture gap were fixed either via dual minifragment locked plating using a 2.5 and a 2.0 mm plates placed orthogonally onto the medial and posterolateral surface of the ulna, or with a single 3.5 mm locking compression plate placed medially. Biomechanical testing included nondestructive quasistatic axial, torsional, and bending loading, followed by cyclic torsional loading to failure in external rotation simulating supination, with monitoring of the interfragmentary movements via motion tracking.
RESULT
No significant differences between the two plating techniques were detected for axial stiffness, torsional stiffness in supination and pronation, bending stiffness in varus and valgus, as well as posterior and anterior bending stiffness, P ≥ .094. Under cyclic loading over 2,000 cycles, dual minifragment locked plating demonstrated overall significantly bigger angular displacement versus single locked plating, P ≤ .018. However, no significant differences were registered between the two fixation techniques for overall shear displacement across the fracture gap over 2,000 cycles, P ≥ .312. Number of cycles until catastrophic failure was not significantly different between the techniques, P = .203. All constructs treated with both plating methods failed because of bone breakage at the most distal screw.
CONCLUSION
From a biomechanical perspective, a dual minifragment construct implementing a 2.5 mm and a 2.0 mm locking plates offers comparable stability for fixation of ulna shaft fractures versus 3.5 mm single locked plating, featuring similar stiffness and shear displacement at the fracture site under torsional loading.
CLINICAL RELEVANCE
Dual minifragment locked plating offers biomechanical stability comparable to to that of a standard 3.5 mm plate fixation of ulna shaft fractures, making it a potential alternative to the latter that may minimize soft tissue irritation; however, clinical research is necessary to confirm its efficacy and safety in vivo.