Clavicle fractures are a common injury of the shoulder girdle, and a vast majority of these injuries encompass the middle-third of the clavicle. In the past, these fractures were commonly treated non-operatively because they were thought to heal with a low rate of malunion and functional deficits. However, a trend towards operative management of certain fracture types has been observed recently due to studies indicating increased patient dissatisfaction and functional deficits of the shoulder complex following non-operative treatment. Today’s literature suggests that some degree of malunion universally occurs if any fracture dis- placement is present and symptomatic malunion may be more common than previously reported. Furthermore, a recent prospective randomized trial showed improved functional outcomes and lower non-union and malunion rates for surgical fixation. Operative treatment has also been reported to have financial benefits for the patient due to expedited return to work, decreased pain medication consumption, and less time spent in physical therapy. Therefore, a biomechanical evaluation of surgical treatments for mid-shaft clavicle fractures has become necessary to assist clinicians in deciding the optimal surgical method for treatment.
Surgical management of middle-third clavicle fractures may include various techniques for reduction and fixation of the injury. Plate fixation is considered the ‘‘gold standard’’ of operative treatment, providing immediate rigid fixation. Intramedullary (IM) fixation devices are another option, which can be accomplished with less soft tissue dissection, more cosmetic incisions, and they may permit callus formation due to the relative stability with a different complication profile from plate fixation. These complications include plate loosening, plate angulation, plate breakage, irritation of the brachial plexus, infection, delayed union, malunion, non-union, and re-fracture. In addition, complications with IM fixation have been reported and include hardware prominence, implant migration, implant breakage, infection, and re-fracture. The advantages of IM fixation, such as smaller incisions, less dissection and soft tissue stripping, relative protection of the supraclavicular nerves, the load sharing nature of the device, and the ability to remove the implant with the patient under local anaesthesia have been demonstrated in the literature.
To date, little biomechanical data are available investigating and comparing the clinical application and clinically relevant biomechanical strength of plate fixation and locked IM devices. Additionally, no biomechanical data has been reported on the strength of the healed clavicle following hardware removal. The purpose of this study was to biomechanically evaluate the repair strength of a superior locking clavicle plate and a new generation locked IM fixation device for middle-third clavicle fractures in a composite bone model. Comparison between the two constructs to the natural intact state was used to evaluate the biomechanical characteristics of the devices. In addition, the biomechanical stability of the intact clavicle after hardware removal of both devices was assessed. Plate repair was hypothesized to provide higher strength than IM device repair, and IM device removal was predicted to result in higher strength relative to plate removal.