Complex Scapula Fractures: Open Reduction, Internal Fixation

Peter A. Cole

Akhil Reddy

INDICATIONS

Scapula fractures are uncommon injuries representing 0.3% of fractures.¹ They occur predominantly as a result of a high-energy driving force usually from lateral or cephalad. With the development of modern techniques in internal fixation, and a better understanding of radiographic indications, surgeons began repairing select scapula fractures utilizing the Arbeitsgemeinschaft für Osteosynthesefragen (AO) principles of anatomic reduction, stable internal fixation, and early functional rehabilitation leading to a renewed interest in the operative management.²^, ³^, ⁴^, ⁵^, ⁶^, ⁷^, ⁸^, ⁹ ^and ¹⁰

Despite surgical advances, the majority of scapula fractures are best managed conservatively. Even at a busy level I trauma center only 12% to 13.6% of scapula fractures presenting through the emergency department underwent surgery.³^,⁷ At centers less familiar to operative treatment for the scapula, this number can be even lower.¹¹^,¹²

Open reduction and internal fixation (ORIF) of intra-articular glenoid fractures is indicated when there is more than 4 mm of articular step-off and instability and more than 20% of the glenoid is involved.¹³^, ¹⁴^, ¹⁵^, ¹⁶^, ¹⁷^, ¹⁸^, ¹⁹^, ²⁰ ^and ²¹ Besides the degree of articular step-off, gap, and percentage of joint involvement, the decision for surgery should be placed in context with the patient’s job, age, activity level, physiologic status, and expectations for function. The surgical indications for displaced extra-articular scapula fractures are controversial because there are no high evidence level studies comparing operative versus nonoperative treatment in comparable cohorts. When the body or neck is fractured, there is medial-lateralization of the cephalad and caudad fragments leading to shortening of the rotator cuff muscle-tendon unit. Such deformity can lead to weakness and fatigability of the shoulder, as well as impingement and scapulothoracic incongruity.²²^, ²³ ^and ²⁴

While the exact numbers are debated, experts share a common range of indications.²^,⁸^,²⁵^, ²⁶ ^and ²⁷ An authors’ algorithm summarizing decision making based on operative indications is included in Figure 6-1.

FIGURE 6-1 The author’s preferred algorithm for the management of scapula fractures.

(From Cole P, Shafiq B. Scapula fractures: open reduction internal fixation. In: Wiss D, ed. Master Techniques in Orthopaedic Surgery: Fractures. 3rd ed. Philadepphia, PA: Lippincot Williams & Wilkins; 2013.)

FIGURE 6-2 A, Lateral border offset sometimes called medialization, is the offset of the cephalad and caudal parts of the lateral border measured by dropping a vertical from each edge and measuring between the two lines (gold arrows). This measurement can be performed on an anteroposterior scapula radiograph as well. Note from posterior, because the cephalad border is covered, an approximation of its location was made. B, Scapula angulation is measured on the orientation reflecting the scapula Y view and can also be measured on a radiograph, albeit slightly less accurately. Lines are drawn down the lateral borders of the cephalad and caudal fragments to obtain this angle as shown by the yellow arrow. C, Glenopolar angle is between the lines drawn parallel to the face of the glenoid and then from the apex of the glenoid through the inferior pole. This is measured off the posteroanterior view of the scapula.

FIGURE 6-3 This is a chest radiograph of a snowmobiler who hit a tree and sustained a forequarter lateral implosion injury. There is evidence of subcutaneous emphysema, and the displaced scapula and clavicle constitute a double lesion of the superior shoulder suspensory complex, which is very unstable (yellow arrows). Making it even more unstable are the very displaced rib fractures that constitute a subscapular flail chest.

FIGURE 6-4 A, Three-dimensional computed tomography (3D CT) scan of a complex scapula fracture involving the lateral border and a completely displaced coracoid fracture. This is a variant of the double lesion of the superior shoulder suspensory complex (SSSC). B, A 3D CT scan of a complex scapula fracture involving the lateral border and a completely dislocated acromioclavicular joint. This is a variant of the double lesion of the SSSC.

FIGURE 6-5 A, A 3D CT showing a displaced comminuted acromion fracture. B, A 3D CT showing a displaced complex coracoid fracture with extension at the base just medial to the suprascapular notch.

Lateral border offset (sometimes referred to as medialization) >20 mm on an anteroposterior (AP; Grashey) view radiograph of the shoulder (Figure 6-2A)
Angular deformity >45° as seen on a scapular Y radiograph of the shoulder (Figure 6-2B)
Lateral border offset >15 mm plus angular deformity >30°
Glenopolar angle <22° as measured on a true AP Grashey view radiograph of the shoulder (Figure 6-2C)
Displaced double lesions of the superior shoulder suspensory complex (SSSC)
- Both the clavicle and scapula fractures displaced >10 mm (Figure 6-3)
- Acromioclavicular dislocation or coracoid fracture and scapula fracture displaced >10 mm (Figure 6-4A and B)
- Acromial fracture >.5 cm or coracoid >1 cm of displacement (Figure 6-5A and B)

The term superior shoulder suspensory complex (SSSC) indicates the osseoligamentous relationship between the acromion, coracoid, and glenoid and intervening ligaments, described by Goss in 1993²⁸ (Figure 6-6). Goss theorized that, if there were two disruptions in this “ring,” then the glenohumeral joint would be “floating,” representing discontinuity between the axial and appendicular skeleton. The term “floating shoulder” was coined by Ganz and is a version of a “double disruption” to the SSSC with injury to the clavicle and scapula neck.²⁹ We agree with Edwards et al. and Ramos et al. that surgery is not indicated when each component of the double displacement is stable and minimally displaced.³⁰^,³¹ However, when both are displaced, ORIF of the clavicle and scapula provide reliably good outcomes.

FIGURE 6-6 This illustration depicts the superior shoulder suspensory complex, which is an osseoligamentous ring made up of the structures along the dotted line. Goss theorized that, if two structures in the ring were disrupted, then a “floating shoulder” lesion would be present, implying that there would be no osseous or ligamentous continuity between the axial skeleton and the forequarter.

Contraindications to scapula surgery include extra-articular scapular fractures that are displaced <15 mm and angulated <25° because the outcomes of nonoperative treatment for even moderately displaced scapula fractures are uniformly good, even in the case a minimal displaced, stable floating shoulders.³²^, ³³^, ³⁴^, ³⁵^, ³⁶^, ³⁷ ^and ³⁸

Severe brachial plexus injuries are not contraindications for surgery, and every effort should be made to restore shoulder symmetry, for the expectation of future recovery, reconstructive procedures, or glenohumeral arthrodesis. Additionally, although severe traumatic brain injury and chest trauma affect timing of surgery, which should occur after patient stabilization, these conditions should not deter operative intervention because of the challenges of future reconstructive surgeries in severe deformity.

Isolated fractures of the acromion or coracoid process usually result from a direct blow to the superior shoulder (acromion) or traction injury involving the biceps and coracobrachialis (coracoid). If an acromion fracture is displaced more than .5 cm, or a coracoid fracture displaced >1 cm, there is an ipsilateral scapula body or glenoid fracture, or there is multiple disruption of the SSSC, then ORIF is warranted.³⁹^, ⁴⁰^, ⁴¹^, ⁴²^, ⁴³^, ⁴⁴ ^and ⁴⁵ Less tolerance for acromial fracture displacement than coracoid fractures is due to the encroachment on the subacromial space and the propensity for further displacement.

PREOPERATIVE PREPARATION (HISTORY, PHYSICAL EXAMINATION, DIAGNOSTICS)

History

Fractures of the scapula usually occur as the result of high-energy blunt trauma with strong forces applied to the shoulder. Although many systems of classification have been developed, both the Ideberg and AO/Orthopaedic Trauma Association (OTA) classifications are most useful today (Figures 6-7 and 6-8). Partial articular fractures, usually involving the anterior glenoid, are commonly associated with anterior shoulder dislocations. These fractures contain the origin of the inferior glenohumeral ligament and are often referred to as bony Bankart lesions.⁴⁶ If shoulder instability is present with recurrent clinical subluxation of the humeral head by history, or on radiographic or physical examination, then operative intervention is recommended. These partial articular glenoid fractures are more common in sports.

FIGURE 6-7 This image depicts the Ideberg classification as modified by Mayo et al It is a classification specific for intra-articular glenoid fractures and accounts for commonly associated fractures of the body and processes and is helpful in determining surgical approach.

FIGURE 6-8 This figure is the AO/OTA classification for scapula fractures as modified in 2007. Although it provides a systematic way of classifying scapula fractures, it has not been developed by correlating identified patterns of injury or combined injuries.

(Adapted from Marsh JL, Slongo TF, Agel J, et al. Fracture and dislocation classification compendium—2007: Orthopaedic Trauma Association classification, database and outcomes committee. J Orthop Trauma. 2007;21(10 suppl):S1-S133.)

A second type of scapula fracture involves the glenoid neck and body with or without articular involvement, and this pattern most commonly occurs following high-energy trauma. The most common mechanism of injury is motorcycle, motorized recreational vehicles, and motor vehicle accidents. Associated injuries occur in up to 90% of patients in this group, and a thorough physical examination is necessary to avoid overlooking serious concomitant injuries.¹³^,¹⁷^,⁴² Because of the high associated injury rate, inquiry regarding other bodily symptoms is paramount. It is a common misconception that scapulothoracic dissociation occurs in combination with scapula fractures, but this is generally not the case as this devastating injury results from a violent traction force to the upper extremity.⁴⁷

Physical Examination

The physical examination must be thorough as associated injuries are common particularly to the spine, cranium, and thorax. When possible, the shoulder and upper extremity should be examined with the patient sitting or standing to give good access to the posterior forequarter and to display functional instability with gravity. Ipsilateral neurologic and other fractures are more common than not in operatively indicated fractures. Medial and caudal displacement of the shoulder (“drooping” or “ptosis”) may be obvious producing marked asymmetry. Particularly if the patient is upright and attempts to move the extremity, the shoulder medializes as the caudal segment of the scapula rotates forward over the thorax. This drooping is associated with poor subjective and functional outcomes.³¹^,⁴⁸^,⁴⁹ In some patients with scapula and multiple rib fractures, the chest wall fails as a secondary support to scapula and contributes to deformity, which is accentuated further when a displaced clavicle fracture is associated with the constellation of fractures (Figure 6-9). This condition has been referred to as the forequarter lateral implosion injury complex.

FIGURE 6-9 This example of a forequarter lateral implosion injury highlights the mechanism of injury and force vector, driving the scapula into the chest cavity, fracturing the hemithorax and the clavicle as well as the scapula. It is important to treat the entirety of this fracture complex inclusive of the chest wall.

Skin integrity should be assessed as abrasions are common after a direct blow to the shoulder. Generally, surgery should be delayed until there is skin re-epithelialization around 7 to 14 days to decrease the chance of infection. Ipsilateral, concomitant, neurovascular injuries are common and require a very careful assessment of the brachial plexus and peripheral pulses. Brachial plexus injury occurs in over 10% of patients with scapula fractures.¹⁹^,³⁵^,⁵⁰ Axillary nerve sensation and ability to isometrically set the deltoid should be assessed. The suprascapular nerve is vulnerable and commonly injured in association with fractures that extend into the spinoglenoid notch at the base of the acromion¹⁰ (Figure 6-10). Poor outcomes after ORIF of scapula fractures are most often associated with severe peripheral nerve injury.⁷^,⁹^,¹⁹^,²⁶^,⁴³^,⁵¹

FIGURE 6-10 This true scapula neck fracture into the anatomic neck enters the spinoglenoid notch where it is displaced right in the region where the suprascapular nerve exits (yellow arrow). This fracture variant is associated with suprascapular nerve injury, and care must be taken during dissection and exposure to explore and protect the neurovascular bundle here.

Radiographic Studies

Because high-energy scapula fractures often present in an emergent setting, chest radiography and computed tomography (CT) scans are routinely acquired during the trauma evaluation. If a scapula fracture is identified on the screening chest radiograph, dedicated scapular radiographs should be obtained. These include a true AP shoulder (Grashey), scapula Y, and axillary or Velpeau views. When possible, we recommend upright views to assess functional instability of the SSSC. If an intra-articular glenoid fracture is detected on any radiograph, a 2D CT scan with 1- to 2-mm axial cuts plus coronal and sagittal reformation is helpful for fracture characterization. An AP radiograph of the opposite shoulder is helpful to define asymmetry and comparative displacement. The 3D CT scan is the gold standard for evaluation of displacement, treatment decision, and surgical planning²^,⁵^,⁵²^, ⁵³^, ⁵⁴ ^and ⁵⁵ (Figure 6-11A and B). When conservative treatment is chosen, serial radiographs should be performed weekly for at least 2 weeks as progressive displacement occurs not uncommonly between 9 and 15 days post injury.⁵⁶

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