Low-Profile Dual Small Plate Fixation Is Biomechanically Similar to Larger Superior or Anteroinferior Single Plate Fixation of Midshaft Clavicle Fractures

Abstract

Background: Limited biomechanical data exist for dual small plate fixation of midshaft clavicle fractures, and no prior study has concurrently compared dual small plating to larger superior or anteroinferior single plate and screw constructs. Purpose: To biomechanically compare dual small orthogonal plating, superior plating, and anteroinferior plating of midshaft clavicle fractures by use of a cadaveric model. Study Design: Descriptive laboratory study. Methods: The study used 18 cadaveric clavicle specimens (9 pairs total), and 3 plating techniques were studied: anteroinferior, superior, and dual. The dual plating technique used smaller diameter plates and screws (1.6-mm thickness) than the other, single plate techniques (3.3-mm thickness). Each of the 9 clavicle pairs was randomly assigned a combination of 2 plating techniques, and randomization was used to determine which techniques were used for the right and left specimens. Clavicles were plated and then osteotomized to create an inferior butterfly fracture model, which was then fixed with a single interfragmentary screw. Clavicle specimens were then potted for mechanical testing. Initial bending, axial, and torsional stiffness of each construct was determined through use of a randomized nondestructive cyclic testing protocol followed by load to failure. Results: No significant differences were found in cyclical axial ( P = .667) or torsional ( P = .526) stiffness between plating groups. Anteroinferior plating demonstrated significantly higher cyclical bending stiffness than superior plating ( P = .005). No significant difference was found in bending stiffness between dual plating and either anteroinferior ( P = .129) or superior plating ( P = .067). No significant difference was noted in load to failure among plating methods ( P = .353). Conclusion: Dual plating with a smaller plate-screw construct is biomechanically similar to superior and anteroinferior single plate fixation that uses larger plate-screw constructs. No significant differences were found between dual plating and either superior or anteroinferior single plating in axial, bending, or torsional stiffness or in bending load to failure. Dual small plating is a viable option for fixing midshaft clavicle fractures and may be a useful low-profile technique that avoids a larger and more prominent plate-screw construct. Clinical Relevance: Plate prominence and hardware irritation are commonly reported complaints and reasons for revision surgery after plate fixation of midshaft clavicle fractures. Dual small plate fixation has been used to improve cosmetic acceptability, minimize hardware irritation, and decrease reoperation rate. Biomechanically, dual small plate fixation performed similarly to larger single plate fixation in this cadaveric model of butterfly fracture.

Finite element analysis of dual small plate fixation and single plate fixation for treatment of midshaft clavicle fractures

“…The anteroinferior plate yielded values of 3.18% and 18.91% under axial compressive and cantilever bending modes, respectively. These findings were similar to that of Thomas et al [16], who found that dual plate fixation was biomechanically similar to superior and anteroinferior single plate fixation.…”

“…However, the dual plate fixation model indicated greater stability for fracture treatment. [10,11,13,14,16]. It is meaningful for surgeons to evaluate the biomechanical performance of implants for the reason of improving the treatment result of clavicle fracture.…”

“…On the contrary, higher patient cosmetic acceptability has been reported with small single plate fixation compared with larger, more prominent plates (95% vs 50%, respectively). Recently, excellent clinical outcomes, 100% union rate, and 0% reoperation rate have been reported with dual small plate fixation [7,10,11,[13][14][15][16]. This has caused clinical interest in dual small plating, to minimize hardware irritation and reoperation rates.…”

Single versus dual orthogonal plating for comminuted midshaft clavicle fractures: a biomechanics study

“…Under cantilever bending, traditional superior plate fixation failed at 55 Nm (577 N at 95 mm). This is favourable to load to failure reported in prior studies: Celestre et al reported failure at 36 Nm (300 N at 120 mm) with 3.5-mm superior locking plates [19], Ziegler et al reported failure at 20 Nm (201 N at 100 mm) with a 3.5-mm superior plate [22], Smith et al reported failure at 18 Nm with a superior precontoured plate [26] and Drosdowech et al reported failure through plate bending at 8 to 22 Nm in a model with an inferior cortical defect [27]. We suspect differences in fixation constructs, clavicle models and testing methodology are likely the source of the substantial interstudy variation observed.…”

“…Ziegler et al compared dual mini-fragment plating to traditional unilateral plating in cadaver clavicles with a simulated inferior butterfly fragment [22]. No significant differences in stiffness or strength were observed between dual mini-fragment plating compared to traditional unilateral plating.…”