A hybrid approach to mid-shaft clavicle fixation

作者：Rawlings Mathew; Knox David; Patel Minoo; Ackland David^*

来源：Injury-International Journal of the Care of the Injured, 2016, 47(4): 893-898.

DOI：10.1016/j.injury.2016.01.042

• Clavicle fracture
• Biomechanics
• Surgery
• Locking screw
• Vascular injury

Background: The purpose of this study was to demonstrate the strength characteristics of a hybrid uni-cortical construct for clavicle fixation. The technique reported aims to combine benefits of uni-cortical fixation with stability comparable to traditional bi-cortical fixation. The approach utilises long, oblique uni-cortical screws at the distal ends of the plate acting as surrogate bi-cortical screws. Locked uni-cortical screws positioned centrally provide bending and torsion strength to the construct. This alternative hybrid uni-cortical technique does not require far cortex screw or drill penetration required in bi-cortical fixation techniques, thus avoiding potentially catastrophic vascular and or neurologic injury. The purpose of this study was to compare the mechanical behaviour of the hybrid uni-cortical construct to standard bi-cortical fixations under both torsion and bending loads.
Method: Thirty osteotomized human cadaveric clavicles were randomly allocated to three surgical fixation techniques: bi-cortical locked screw fixation, bi-cortical non-locked screw fixation and hybrid uni-cortical screw fixation. Each clavicle construct was tested non-destructively under torsional loading, and then under cantilever bending to failure. Construct bending and torsional stiffness, as well as ultimate failure strength, were measured.
Results: There were no significant differences between uni-cortical or bi-cortical fixation constructs in either bending stiffness or ultimate bending moment (p > 0.05); however, there was a trend towards greater bending stiffness in the hybrid construct. The uni-cortical hybrid fixation technique displayed a significantly lower mean torsional stiffness value when compared with the bi-cortical locked screw fixation (mean difference: 134.4 Nmm/degrees, 95% confidence interval [ 32.3, 236.4], p = 0.007).
Conclusion: A hybrid uni-cortical approach to clavicle plate fixation that may improve screw purchase and reduce risk of intra-operative vascular damage demonstrates comparable bending strength to current bi-cortical approaches.

• 出版日期2016-4