Comparison of 4 Methods for Dynamization of Locking Plates: Differences in the Amount and Type of Fracture Motion.
J Orthop Trauma
; 31(10): 531-537, 2017 Oct.
Article
en En
| MEDLINE
| ID: mdl-28657927
ABSTRACT
BACKGROUND:
Decreasing the stiffness of locked plating constructs can promote natural fracture healing by controlled dynamization of the fracture. This biomechanical study compared the effect of 4 different stiffness reduction methods on interfragmentary motion by measuring axial motion and shear motion at the fracture site.METHODS:
Distal femur locking plates were applied to bridge a metadiaphyseal fracture in femur surrogates. A locked construct with a short-bridge span served as the nondynamized control group (LOCKED). Four different methods for stiffness reduction were evaluated replacing diaphyseal locking screws with nonlocked screws (NONLOCKED); bridge dynamization (BRIDGE) with 2 empty screw holes proximal to the fracture; screw dynamization with far cortical locking (FCL) screws; and plate dynamization with active locking plates (ACTIVE). Construct stiffness, axial motion, and shear motion at the fracture site were measured to characterize each dynamization methods.RESULTS:
Compared with LOCKED control constructs, NONLOCKED constructs had a similar stiffness (P = 0.08), axial motion (P = 0.07), and shear motion (P = 0.97). BRIDGE constructs reduced stiffness by 45% compared with LOCKED constructs (P < 0.001), but interfragmentary motion was dominated by shear. Compared with LOCKED constructs, FCL and ACTIVE constructs reduced stiffness by 62% (P < 0.001) and 75% (P < 0.001), respectively, and significantly increased axial motion, but not shear motion.CONCLUSIONS:
In a surrogate model of a distal femur fracture, replacing locked with nonlocked diaphyseal screws does not significantly decrease construct stiffness and does not enhance interfragmentary motion. A longer bridge span primarily increases shear motion, not axial motion. The use of FCL screws or active plating delivers axial dynamization without introducing shear motion.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Placas Óseas
/
Resistencia al Corte
/
Fracturas del Fémur
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Fijación Interna de Fracturas
/
Modelos Anatómicos
Límite:
Humans
Idioma:
En
Revista:
J Orthop Trauma
Asunto de la revista:
ORTOPEDIA
/
TRAUMATOLOGIA
Año:
2017
Tipo del documento:
Article