The clavicle is an S-shaped bone with unique anatomical features. The name is derived from the Latin name for a similarly shaped musical instrument. The apices of the bone are anteromedial and posterolateral with a transition occurring approximately two thirds of the way from the sternal attachment. There is not a discrete medullary cavity associated with the bone as there is a capacious medial shape, tubular mid-portion, and flatter lateral portion (Fig. 15.2a–c). The two joints at either end are both diarthrodial joints, which have little inherent bony stability. They derive most of their stability from strong ligamentous and capsular attachments. The sternoclavicular joint is responsible for the majority of motion associated with the clavicle, with at least 35° of elevation-depression, 35° of protraction-retraction, and 50° of rotation. This contrasts with the acromioclavicular joint, which is responsible for much less motion [13, 14].

The carotid artery, vagus nerve, and jugular vein pass deep to the medial clavicle en route to the head and neck. The brachial plexus travels inferoposterior to the clavicle en route to the upper extremity. Deforming forces to the clavicle after injury include the sternocleidomastoid muscle which attaches to the superior border of the medial clavicle and the pectoralis major which attaches to the inferior border. The trapezius attaches to the superior border of the distal clavicle, while the deltoid originates from the distal/inferior clavicle. The conoid and trapezoid ligaments attach to the distal third of the clavicle and anchor it to the coracoid [15, 16]. The mid-portion is free of these muscular attachments and represents a weaker area of the bone. The different deforming forces lead to characteristic displacement patterns after fracture [17, 18].

With the anterior approach to the clavicle, the first structures encountered that should be identified are branches of the supraclavicular nerves (Fig. 15.3). These course from superior to inferior over the platysma musculature. The brachial plexus and subclavian artery and vein run inferior to the clavicle and are very closely approximated in the middle third of the bone (Fig. 15.4a, b). Inferior to the distal clavicle, the subacromial artery is encountered as well. This is relevant in the cases of inferior exposure of the bone in ensuring that inferiorly directed drills and screws are safely applied [19]. Knowledge of these anatomical relationships is critical during drill trajectory and orientation of instrumentation and implants (Fig. 15.5a, b) [20].

The length of plate fixation depends on the quality of the bone, the degree of comminution, the type of plate, the age of the patient, and their anticipated compliance. Plate placement can be in the superior or anterior position. Anterior plate placement was shown in one biomechanical cadaveric study to provide greater stiffness [31], and it has been associated with less prominence of the plate and diminished risk of injury to nerve or vessels and failure of fixation [32, 33]. However, superior plating remains more common in clinical practice [33], is familiar for most surgeons, and may yield a biomechanical advantage in middle third clavicle fractures over anterior plating.

The incision is taken down through subcutaneous tissue to expose the fascia surrounding the platysma musculature. The platysma is then cut directly to the periosteum, and cautery is useful for this vascular plane. A thick cuff is preserved to facilitate later repair. Any identified cutaneous branches of the supraclavicular nerve, usually present more medially within the platysma muscle, are preserved to prevent peri-incisional numbness. The patient should be warned of this potential for numbness preoperatively so expectations are managed. Minimal, but sufficient, periosteal dissection to allow for fracture exposure, reduction, and plate placement is performed. Careful retraction should respect posterior and inferior vital structures. Bone reduction forceps can be placed on either end of the fracture and used to manipulate the bone fragments back into position. Free draping of the arm allows elevation and rotation to achieve the appropriate alignment is useful and minimizes soft tissue trauma in obtaining reduction. Once aligned, bone reduction forceps placed in pilot holes on each side of the fracture can be used when stable bone ends allow for compression. K-wires can be used to provisionally hold large butterfly fragments. Greater comminution should be bridged, and devascularization and exposure of the comminution zone should be avoided. In such cases, the fracture is fixed distally first, and the plate used as a reduction aid to restore length and rotation. With the fracture reduced, lag screw fixation is employed when possible. Small, comminuted fragments that cannot be captured with lag screw fixation can be fixed in location with suture, and such fractures should be spanned with a plate in the bridging mode (Fig. 15.11a, b). A plate of the appropriate size is selected and contoured to the patient’s anatomy. The goal should be a minimum of three bicortical screws on each side of the fracture. Straight dynamic compression plates are often prominent, while pelvic recon plates may not be strong enough for the forces acting on the fracture: for these reasons, the implant of choice is a pre-contoured compression plate designed specifically for clavicular fixation.

A single flat-plate radiograph or C-arm image should be obtained prior to closure to ensure that no screw tips are prominent as brachial plexus irritation or trauma to the subclavian artery or vein has been reported. It can be helpful to place a flat plate behind the patient’s shoulder prior to prepping and draping, so that the cassette is in position for good imaging without disruption of the sterile field after fixation. Closure of the platysma and fascia as one layer is performed using 2-0 braided sutures. The subcutaneous tissues are re-approximated with inverted sutures, and the skin is best approximated with subcuticular absorbable monofilament suture that provides a cosmetic closure.

Sternoclavicular dislocations occur as a result of direct trauma or indirect forces through the shoulder. In skeletally immature patients up to approximately 20 years, medial physeal fractures can be mistaken for dislocations. Dislocations are either anterior or posterior. Concomitant injury to mediastinal structures in posterior dislocations must be ruled out. These may include injuries to the trachea or larynx, and esophagus. The brachiocephalic trunk and neurologic injury to the phrenic nerve should be ruled out with a thorough history and physical examination. A CT angiogram or arteriography is indicated in posterior dislocations to assess the great vessels for injury that may include intimal damage, pseudo-aneurysm, or simple compression. These findings will help guide treatment.

When attempting manipulation of the posterior dislocation, it is important to have communicated directly with a cardiac surgeon so that they can be on standby in the event of a major arterial hemorrhage. This is imperative if a preoperative arteriographic radiography has not been done or has shown any abnormality. Postreduction clinical examination and observation are mandatory. In the acute setting, closed reduction and stabilization is recommended for both anterior and posterior dislocations to restore anatomy, reduce deformity, and improve long-term function. The decision to proceed with open reduction if closed reduction is unsuccessful depends on the health and activity level of the patient. Physeal disruptions are also amenable to operative fixation. In such cases, a plate is used to capture the medial fragment, ideally with locked fixation to avoid loosening and pullout (Fig. 15.15a–e). Suture fixation alone with heavy-braided suture is possible. These patients must be immobilized for approximately 2 weeks because they can experience cutout due to deforming forces.

For closed reduction of anterior dislocations, the patient is placed supine with a pad between the shoulders, and direct pressure is applied on the medial clavicle in a posterior direction. These can be quite stable after reduction: if not, an open reduction may be indicated in a high-demand patient. The technique for posterior dislocation involves the placement of a pad between the scapulae; traction is applied to an extended/abducted arm with counter traction or posterior pressure applied to the shoulder. A sterile towel clip can also be used percutaneously to grasp the medial clavicle and reduce it (Fig. 15.16a). Posterior dislocations are frequently stable once reduced, but if closed reduction fails, open reduction and stabilization is performed with heavy-braided suture repair of the capsule and periosteum (Fig. 15.16b, c). Ligamentous reconstruction has been described, but typically for chronic dislocation variants and they are fraught with high failure rates. The authors’ preferred management strategy for painful chronic dislocations is medial clavicle resection with imbrication of the scar tissue and capsule. Generally patients are very satisfied with resolution of both deformity and pain. The use of smooth pins for stabilization of dislocations is to be avoided due to the potentially catastrophic complication of pin loosening and migration.