CLAVICLE FRACTURES

 

 

 

EPIDEMIOLOGY

• Clavicle fractures account for approximately 2.6% of all fractures and for 44% to 66% of fractures about the shoulder.

• Middle third fractures account for 80% of all clavicle fractures, whereas fractures of the lateral and medial third of the clavicle account for 15% and 5%, respectively.

  ANATOMY

• The clavicle is the first bone to ossify (fifth week of gestation) and the last ossification center (sternal end) to fuse, at 22 to 25 years of age.

• The clavicle is S-shaped, with the medial end convex forward and the lateral end concave forward.

• It is widest at its medial end and thins laterally.

• The medial and lateral ends have flat expanses that are linked by a tubular middle, which has sparse medullary bone.

• The clavicle functions as a strut, bracing the shoulder from the trunk and allowing the shoulder to function at optimal strength.

• The medial one-third protects the brachial plexus, the subclavian and axillary vessels, and the superior lung. It is strongest in axial load.

• The junction between the two cross-sectional configurations occurs in the middle third and constitutes a vulnerable area to fracture, especially with axial loading. Moreover, the middle third lacks reinforcement by muscles or ligaments distal to the subclavius insertion, resulting in additional vulnerability.

• The distal clavicle contains the coracoclavicular ligaments.

  • The two components are the trapezoid and conoid ligaments.

  • They provide vertical stability to the acromioclavicular (AC) joint.

  • They are stronger than the AC ligaments.

     

    MECHANISM OF INJURY

• Falls onto the affected shoulder leading to a bending force account for most (87%) of clavicular fractures, with direct impact accounting for only 7% and falls onto an outstretched hand accounting for 6%.

• Although rare, clavicle fractures can occur secondary to muscle contractions during seizures or secondary to minimal trauma due to pathologic bone or as stress fractures.

  CLINICAL EVALUATION

• Patients usually present with splinting of the affected extremity, with the arm adducted across the chest and supported by the contralateral hand to unload the injured shoulder.

• A careful neurovascular examination is necessary to assess the integrity of neural and vascular elements lying posterior to the clavicle.

• The proximal fracture end is usually prominent and may tent the skin. Assessment of skin integrity is essential to rule out open fracture.

• The chest should be auscultated for symmetric breath sounds. Tachypnea may be present as a result of pain with inspiratory effort; this should not be confused with diminished breath sounds, which may be present from an ipsilateral pneumothorax caused by an apical lung injury.

  ASSOCIATED INJURIES

• Up to 9% of patients with clavicle fractures have additional fractures, most commonly rib fractures.

• Most brachial plexus injuries are associated with proximal third clavicle fractures (traction injury).

• The skin is often abraded as a result of the injury mechanism.

  RADIOGRAPHIC EVALUATION

• Standard anteroposterior radiographs are generally sufficient to confirm the presence of a clavicle fracture and the degree of fracture displacement.

• A 30-degree cephalad tilt view provides an image without the overlap of the thoracic anatomy.

• An apical oblique view can be helpful in diagnosing minimally displaced fractures, especially in children. This view is taken with the involved shoulder angled 45 degrees toward the x-ray source, which is angled 20 degrees cephalad.

• A chest x-ray allows for side-to-side comparison, including normal length.

• Computed tomography may be useful, especially in proximal third fractures, to differentiate sternoclavicular dislocation from epiphyseal injury, or distal third fractures, to identify articular involvement.

  CLASSIFICATION

  Descriptive

  Clavicle fractures may be classified according to anatomic description, including location, displacement, angulation, pattern (e.g., greenstick, oblique, transverse), and comminution.

  A lman

• Group I: fracture of the middle third (80%). This is the most common fracture in both children and adults; proximal and distal segments are secured by ligamentous and muscular attachments.

• Group II: fracture of the distal third (15%). This is subclassified according to the location of the coracoclavicular ligaments relative to the fracture:

  Type I: Minimal displacement: interligamentous fracture between the conoid and trapezoid or between the coracoclavicular and AC ligaments; ligaments still intact (Fig. 11.1)

  Type II: Displaced secondary to a fracture medial to the coracoclavicular ligaments: higher incidence of nonunion

  IIA: Conoid and trapezoid attached to the distal segment (Fig. 11.2)

  IIB: Conoid torn, trapezoid attached to the distal segment (Fig. 11.3)

  Type III: Fracture of the articular surface of the AC joint with no ligamentous injury: may be confused with first-degree AC joint separation (Fig. 11.4)

   

   

   

   

   

   

   

   

   

   

   

• Group III: fracture of the proximal third (5%). Minimal displacement results if the costoclavicular ligaments remain intact. It may represent epiphyseal injury in children and teenagers. Subgroups include:‌‌

  Type I: Minimal displacement

  Type II: Displaced

  Type III: Intra-articular

  Type IV: Epiphyseal separation

  Type V: Comminuted

   

  Orthopaedic Trauma Association Classification of Clavicle Fractures See Fracture and Dislocation Classification Compendium at http://www.ota.org/compendium/compendium.html.

  TREATMENT

  Nonoperative

• Most minimally displaced clavicle fractures can be successfully treated nonoperatively with some form of immobilization.

• Comfort and pain relief are the main goals. A sling has been shown to provide the same results as a figure-of-eight bandage, providing more comfort and fewer skin problems.

• The goals of the various methods of immobilization are as follows:

  • Support the shoulder girdle, raising the lateral fragment in an upward, outward, and backward direction (sling).

  • Depress the medial fragment (figure of eight).

  • Maintain some degree of fracture reduction (both).

  • Allow for the patient to use the ipsilateral hand and elbow.

• Regardless of the method of immobilization utilized, some degree of shortening and deformity usually result.

• In general, immobilization is used for 4 to 6 weeks.

• During the period of immobilization, active range of motion of the elbow, wrist, and hand should be performed.

• Frequent radiographic evaluation until union is needed to detect later displacement.

  Operative

• The surgical indications for midshaft clavicle fractures are controversial and have been changing recently.

• The accepted indications for operative treatment of acute clavicle fractures are open fracture, associated neurovascular compromise, and skin tenting with the potential for progression to open fracture.

• Controversy exists over management of midshaft clavicle fractures with substantial displacement (more than 100%), comminution (“z-deformity”), and shortening (>1 to 2 cm).

  • Although most displaced midshaft fractures will unite, studies have reported shoulder dysfunction and patient dissatisfaction with the resulting cosmetic deformity.

  • There is also more recent evidence that functional outcome may be improved in some of these

    patients with surgical treatment. Furthermore, the presence of a malunion may portend inferior function.

• Controversy also exists over management of type II distal clavicle fractures.

• Some authors have indicated that all type II fractures require operative management.

• Others report that if the bone ends are in contact, healing can be expected even if there is some degree of displacement. In this situation, nonoperative management consists of sling immobilization and progressive range of shoulder motion.

• Operative fixation may be accomplished via the use of:

  • Plate fixation: This is placed either on the superior or on the anteroinferior aspect of the clavicle.

    • Plate and screw fixation requires a more extensive exposure than intramedullary devices but

      has the advantage of more secure fixation counteracting tensile forces.

    • Plate and screw fixation may be prominent, particularly if placed on the superior aspect of the clavicle.

    • Newer low-profile implants and/or anteroinferior placement may preclude this finding.

  • Intramedullary fixation (Hagie pin, Rockwood pin, Sonoma nail): Usually placed in antegrade fashion through the lateral fragment and then in retrograde fashion into the medial fragment or retrograde as a flexible implant that is then stiffened.

    • Use of intramedullary fixation requires frequent radiographic follow-up to monitor the possibility of hardware migration and a second procedure for hardware removal.

    • Older intramedullary pins are prone to skin erosion at the hardware insertion site laterally.

      Historically, these implants have been reported to be associated with complications in up to 50% of cases.

  • Operative treatment of type II distal clavicle fractures consists of reducing the medial fragment to the lateral fragment. This is accomplished by using either coracoclavicular fixation (Mersilene tape, sutures, wires, or screws) or fixation across the AC joint through the lateral fragment and into the medial fragment (lateral clavicle plates).

    COMPLICATIONS

• Neurovascular compromise: This is uncommon and can result from either the initial injury or secondary to compression of adjacent structures by callus and/or residual deformity. Subclavian vessels are at risk with superior plating.

• Malunion: This may cause a bony prominence and may be associated with poorer Disabilities of the Arm, Shoulder and Hand (DASH) scores at 1 year.

• Nonunion: The incidence of nonunion following clavicle fractures ranges from 0.1% to 13.0%, with 85% of all nonunions occurring in the middle third.

  • Factors that have been implicated in the development of nonunions of the clavicle include (1) severity of initial trauma (open wound), (2) extent of initial displacement of fracture fragments,

    (3) soft tissue interposition, (4) refracture, (5) inadequate period of immobilization, and (6)

    primary open reduction and internal fixation.

• Posttraumatic arthritis: This may occur after intra-articular injuries to the sternoclavicular or AC joint.