**1. Introduction**

Clavicle fractures are very common, accounting for 2.6–4% of all fractures [1, 2]. The majority of these, greater than 80%, occur in the midshaft [3]. They are commonly associated with athletic activities such as contact sports (such as football), cycling, and snow sports, and occur typically in a younger male patient group [2]. Undisplaced fractures are usually treated non-operatively, but indications for operative treatment have led to a general consensus that displacement and/or shortening of greater than 20 mm leads to a higher mal-union and non-union rate and is a stronger indication for operative treatment. Zlowodzki et al. [4] reported a 15.1% non-union rate for non-operatively treated displaced clavicle fractures. They identified factors associated with nonunion including displacement, comminution, female sex, and increased age. Postacchini et al. [2] noted 48% of fractures in their study were displaced and 19% were comminuted. This chapter outlines a surgical approach for intramedullary fixation of midshaft clavicle fractures using a cannulated intramedullary screw. A recent systematic review supported a lower incidence of nonunion and

symptomatic malunion in patients who underwent operative fixation of displaced midshaft clavicular fractures compared to conservative management [5].

Furthermore, there is mounting evidence that intramedullary fixation achieves similar or superior functional outcomes to plate fixation, but with lower complication rates [6]. The decision to proceed with operative management will be patient specific and will be affected by factors such as: deformity, disability, patient choice, the local health care system, implant cost and availability, and the overall relative cost/benefit of the procedure. For instance, operative fixation for a tradesperson, dependent on upper limb use, may allow substantially more rapid return to work and reduced offwork costs.
