Low-profile dual mini-fragment plating of diaphyseal clavicle fractures. A biomechanical comparative analysis

Abstract

Abstract Objective Implant removal rates after clavicle plating are high. Recently, low-profile dual mini-fragment plate constructs have proven safe for the fixation of diaphyseal clavicle fractures. Therefore, the aims of this study was to investigate: (1) the biomechanical competence of different dual plate designs in terms of stiffness and cycles to failure, and (2) to compare them against 3.5 mm single superoanterior plating. Methods 12 artificial clavicles were assigned to 2 groups and instrumented with titanium matrix mandible plates as follows: group 1 (2.5 mm anterior+2.0 mm superior) and group 2 (2.0 mm anterior+2.0 mm superior). An unstable clavicle shaft fracture (AO/OTA15.2C) was simulated. Specimens were cyclically tested to failure under craniocaudal cantilever bending, superimposed with torsion around the shaft axis and compared to previous published data of 6 locked superoanterior plates tested under the same conditions (group 3) Results Displacement (mm) after 5000 cycles was highest in group 3 (10.7±0.8) followed by group 2 (8.5±1.0) and group 1 (7.5±1.0), respectively. Both outcomes were significantly higher in group 3 as compared to both groups 1 and 2 (p≤0.027). Cycles to failure were highest in group 3 (19536±3586) followed by group 1 (15834±3492) and group 2 (11104±3177), being significantly higher in group 3 as compared to group 2 (p=0.004). Conclusion Low-profile 2.0/2.0 dual plates demonstrated similar initial stiffness compared to 3.5 mm single plates, however, they revealed significantly lower endurance to failure. Moreover, low-profile 2.5/2.0 dual plates showed significant higher initial stiffness and similar resistance to failure compared to 3.5 mm single locked plates and can therefore be considered as a useful alternative for diaphyseal clavicle fracture fixation. These results complement the promising results of several clinical studies.