Biomechanical Analysis of Superior and Anterior Precontoured Plate Fixation Techniques for Neer Type II-A Clavicle Fractures

Abstract

Objective: There are limited biomechanical data supporting the use of anterior or superior-lateral precontoured clavicle plates for the treatment of displaced Neer type II-A clavicle fractures. The objectives of this study were as follows: (a) compare noncontoured versus precontoured superior plating; (b) compare use of locking versus nonlocking screws in the lateral fragment for superior precontoured plates; and (c) compare superior versus anterior precontoured plates with locking lateral fragment screws. Methods: The following constructs were tested on a synthetic clavicle model simulating a Neer type II-A fracture: (a) superior precontoured plate with locking (SUP-L, n = 6); (b) superior precontoured plate with nonlocking (SUP-NL, n = 8); (c) anterior precontoured plate with locking (ANT-L, n = 7); and (d) superior noncontoured locking compression plate (SUP-LCP, n = 6). Constructs were subjected to cyclical cantilever loads. Construct stiffness and survival (cycles to failure) were documented. Mann–Whitney U tests were performed for group-wise statistical comparison (α = 0.05) of data. Results: The SUP-L construct was significantly stiffer than both SUP-LCP and ANT-L constructs (P < 0.02). The SUP-NL construct was stiffer than the SUP-L (P = 0.03) construct. Both SUP-L and ANT-L precontoured constructs survived longer than the noncontoured SUP-LCP construct (P < 0.022). The SUP-L construct survived longer than the SUP-NL (P = 0.013) and the ANT-L (P = 0.008) constructs. Conclusions: Superior precontoured plates yielded biomechanically superior constructs compared with anterior precontoured and superior noncontoured plates. Using locking screws in the lateral fragment over nonlocking screws may improve overall superior precontoured plate construct survivability. However, our results were limited to a synthetic biomechanical model and require further investigation to establish a clinical correlation.

Relation between diameter of a lateral screw and pull‐out strength in distal clavicle fracture in plates with different geometry: A cadaveric biomechanical study

“…Previously, several biomechanical studies for distal clavicle fracture evaluated and compared the fixation strength between nonanatomical and anatomical plates and between locking head and nonlocking head screws. [26][27][28][29][30] previous studies reported that about 400-600 N strength is required for failure of fixation due to pull-out. 26,28,31 Considering the ultimate pullout strength of 235 N in this study, the distal clavicle locking plate can only be used in cases that allows three or more screws in lateral fixation, due to the significant possibility of failure with lateral fixation using only two screws.…”

“…Previously, several biomechanical studies for distal clavicle fracture evaluated and compared the fixation strength between non‐anatomical and anatomical plates and between locking head and non‐locking head screws 26–30 . However, no investigation has examined the relation between varying screw diameters and fixation strength of the distal clavicle fracture.…”

The anterior head of deltoid in relation to anterior clavicle plating: how much are we releasing?

“…[1] Prior studies have focused on biomechanical advantages of various types of fixation. [2][3][4][5][6][7] Often mid-clavicular shaft fractures are treated with precontoured plates or mini-fragment anterior plate fixation due to possible biomechanical advantage and lower implant removal rates (Fig. 2C).…”