Scapula Fractures

Fractures of the scapula are relatively uncommon, accounting for 3% of all shoulder girdle injuries. These generally occur as the result of high-energy trauma explaining the frequent association with other, often life-threatening, injuries that may be of greater significance than the fracture itself. It is not uncommon for scapular fractures to be overlooked in polytrauma patients and often noticed incidentally on a chest radiograph or CAT scan.

A classification system was developed by Ada and Miller (Table 3), which divided fractures into those involving the acromion, spine and coracoid, type 1, glenoid neck, type 2, intra-articular glenoid fractures, type 3, and isolated scapular body fractures, type 4.

Table 3 Scapular Fracture Classification System

Associated injuries are quite common due to the high-energy mechanisms in which they usually occur. In one study of 148 fractures in 116 scapulae, 96% had associated injuries with upper thoracic rib fractures being the most common. Pulmonary injuries were also common with an overall incidence of 37%, of which 29% were hemopneumothorax and 8% pulmonary contusion. Head injuries were observed in 34%, ipsilateral clavicle fractures were seen in 25%, and 12% of patients had cervical spine injuries, of which 4% had permanent cord injuries.

Management of these fractures is often nonsurgical as poor healing is an infrequent complication due to the rich blood supply from the investing rotator cuff musculature. Nonoperative management consists of admission for a period of 24 hours to assess pulmonary and cardiac status. A brief period of sling immobilization is initiated for comfort, followed by passive range of motion. Most fractures are united by 6 weeks such that active mobilization and strengthening can ensue safely. Maximal functional recovery can take 6–12 months.

Operative indications include intra-articular glenoid fractures with 5 mm of displacement, coracoid fractures with intra-articular extension and more than 5 mm of step-off, glenoid rim fractures with persistent or recurrent glenohumeral instability.

The injury pattern described as the “floating shoulder” deserves attention. This refers to a “double disruption” of the superior shoulder suspensory complex. This complex consists of a bone and soft tissue ring formed by the glenoid, coracoid process, coracoclavicular ligaments, distal clavicle, acromioclavicular joint, and acromion process. Isolated disruption of one of these components is generally tolerated well; however, when two or more structures are damaged, it is thought to produce an unstable situation. This is commonly seen with ipsilateral clavicle and glenoid neck fractures. The treatment of such injuries is somewhat controversial in that good results have been reported with fixation of both the glenoid and clavicle, clavicle alone, and more recently, nonoperative management. At this time, reasonable indications for operative intervention would include glenoid neck fractures with more than 3 cm of medial displacement in combination with injury to another structure. Each patient, however, must be evaluated individually.

Scapulothoracic Dissociation

Scapulothoracic dissociation is an infrequent injury that can be thought of as an internal forequarter amputation, which is almost always seen in conjunction with severe injuries to the brachial plexus and subclavian vessels. It is the result of a massive traction injury causing significant lateral displacement of the scapula relative to its thoracic articulation. According to the paper by Althausen et al., 88% have associated vascular lesions and 94% presented with severe neurologic injuries. A flail extremity resulted in approximately 52%, early amputation in 21%, and death in 10% of patients.

Diagnosis is made clinically by the presence of massive swelling, weakness, pain, tenderness, and absent or diminished pulses. It is crucial not to attribute pulselessness to a more distal injury when a more proximal, life threatening injury may be the underlying cause. Radiographically an AP film of the chest with the cassette oriented transversely may reveal lateral displacement of the scapula. Measurement from the medial border of the scapula to the spinous processes should alert the physician to the possibility of a scapulothoracic dissociation with a distance of more than 1 cm when compared to the opposite side. This may or may not be seen in conjunction with an acromioclavicular separation or clavicle fracture.

Management is controversial but arterial injuries may warrant immediate exploration and repair. As many as 10% of patients who survive the initial injury may die from exsanguination. Brachial plexus exploration may be carried out at the same time. Bony stabilization may be necessary to protect vascular repairs but the role of internal fixation is otherwise less clear.

Glenohumeral Dislocation

Due to its lack of bony constraint, the shoulder is the most commonly dislocated joint in the body. It is not a true ball and socket joint, but more like a golf ball resting on a golf tee. The static restraints to dislocation are composed of the glenoid labrum, capsule, and glenohumeral ligaments, while the rotator cuff musculature provides additional dynamic stability.

Anterior dislocations are by far the most common type. These are usually the result of an eccentric load applied to the arm while in an outstretched position as would be seen in a volleyball player while spiking the ball. Posterior dislocations occur with a posteriorly directed force on an adducted, flexed arm, and also have been noted to occur in patients who are seizing.

An anteriorly dislocated shoulder will present with the arm at the side or in slight abduction and external rotation. Normal loss of the shoulder contour may be seen with a prominent “sulcus” sign. Adduction and internal rotation are usually limited. A patient with a posterior dislocation will hold the arm in an adducted, internally rotated position.

Evaluation should include a thorough neurologic examination prior to any attempted reduction. Neurologic involvement is not infrequent with the axillary nerve being most commonly affected. Vascular status should likewise be documented, as vascular injuries can occur, although less commonly. Radiographic evaluation should also be completed prior to commencing treatment. A standard trauma series as described earlier is extremely helpful in delineating any associated glenoid rim or humeral head impaction fractures.

Reduction is most easily carried out with some form of sedation and or injection of lidocaine into the joint capsule. Gentle traction–counter traction will reduce most dislocations. Irreducible dislocations and fracture dislocations are best managed in the operating room with general anesthesia.

Postreduction, a period of immobilization in a sling from 10 days to 2 weeks is recommended followed by a supervised physical therapy program. In patients younger than 20 years, recurrence rates up to 90% have been reported most likely due to the violent nature of the dislocation and the very commonly associated anterior-inferior labral tear or “Bankart” lesion that occurs. In contrast, patients aged over 40 years commonly have associated rotator cuff tears. A high index of suspicion should be present at follow-up examination of these patients in the early recovery period.

Proximal Humerus Fractures

Proximal humerus fractures are common injuries, especially with our aging population. The majority of these injuries are minimally displaced or nondisplaced and can be treated conservatively. Factors to take into consideration in the treatment plan are age of the patient, hand dominance, bone quality, fracture type, and fracture displacement. Associated injuries in the multitrauma patient are also important in the decision-making process.

Assessment should consist of a thorough neurovascular examination along with a radiographic trauma series. The presence of an expanding axillary mass and absent distal pulses is concerning for a vascular injury. Nerve injuries occur in as many as one-third of patients and are more common with increasing age. In one study the incidence of nerve injury with proximal humeral fracture-dislocations was greater than 50% after age 50. If present, these injuries may take 9 months or more to recover neurologic function, which is often incomplete.

These fractures are classified according to the description by Neer. He described six variations of displaced proximal humerus fractures, and defined displacement as greater than 1 cm or 45 degrees of angulation. The anatomic “parts” consist of the anatomic neck, surgical neck, and greater and lesser tuberosities. Despite poor interobserver reliability, this is the most frequently used classification system. Figure 2 depicts various fracture patterns that are both considered “two-part fractures.” The portion of the humerus that is displaced has clinical relevance due to the varying blood supply of the proximal humerus. Displacement of the anatomic neck for example, has a high chance of disrupting the blood supply and adversely affecting outcome, regardless of the treatment chosen.

Figure 2 Displaced greater tuberosity fracture on left (white arrow), and displaced anatomic neck fracture on right. Both are considered “two-part fractures” according to the Neer classification.