Open Reduction and Internal Fixation of Intra-articular Scapular Fractures

DEFINITION

Intra-articular scapular fractures include fractures of the glenoid cavity, which includes the glenoid rim and the glenoid fossa. They account for 10% of scapular fractures.⁶ Most scapular fractures are extra-articular, and 50% involve the body and spine.
Over 90% of fractures of the glenoid cavity are insignificantly displaced and are managed nonoperatively.³
Significant displacement requires evaluation for surgical intervention to achieve the best possible outcome.

ANATOMY

The scapula is a flat triangular bone with three processes: the glenoid process, the acromial process, and the coracoid process.
The glenoid process consists of the glenoid cavity (the glenoid rim and glenoid fossa) and the glenoid neck.
The glenoid cavity provides a firm concave surface with which the convex humeral head articulates. The average depth of the articular cartilage is 5 mm.
Glenoid cavity fractures are classified according to whether they involve the glenoid rim or the glenoid fossa and the direction of the fracture line (FIG 1).

PATHOGENESIS

Scapular fractures usually are the result of high-energy trauma and have a high rate (90%) of associated bony and soft tissue injuries, both local and distant.⁵
Fractures of the glenoid rim occur when the humeral head strikes the periphery of the glenoid cavity. They are true fractures, not avulsion injuries caused by indirect forces applied to the periarticular soft tissues by the humeral head.
Fractures of the glenoid fossa occur when the humeral head is driven into the center of the concavity. The fracture then promulgates in a number of different directions, depending on the characteristics of the humeral head force.

NATURAL HISTORY

The results of nonoperative treatment of intra-articular scapular fractures usually are good if the fracture displacement is minimal and the humeral head lies concentrically within the glenoid cavity.
Significant displacement can result in posttraumatic degenerative joint disease, glenohumeral instability, and even nonunion.²

PATIENT HISTORY AND PHYSICAL FINDINGS

In addition to the specifics of the injury, it is helpful to obtain an understanding of the functional demands on the extremity. Hand dominance, occupation, and sports participation are all relevant.
A thorough neurovascular examination must be performed. Deficits are evaluated with angiography and electromyography, as necessary.
A thorough soft tissue examination also is warranted. Wounds may represent an open fracture and warrant exploration. Blisters or swelling may delay surgery.

IMAGING AND OTHER DIAGNOSTIC STUDIES

Intra-articular scapular fractures initially are evaluated with a routine scapula trauma radiographic series (a true anteroposterior view of the shoulder with the arm in neutral rotation, a true axillary view of the glenohumeral joint, and a true lateral scapular view; FIG 2A).
Computed tomography (CT) scans and three-dimensional studies with reconstructions can be helpful in evaluating articular congruity and fracture displacement (FIG 2B-D). In addition, the bony relationships should be evaluated for evidence of ligamentous disruption(s) or instability.

NONOPERATIVE MANAGEMENT

Most (over 90%) intra-articular scapular fractures are insignificantly displaced and are managed nonoperatively.
Significantly displaced glenoid fossa and glenoid rim fractures require operative management.

SURGICAL MANAGEMENT

Surgical indications are as follows:
- Rim fractures: 25% or more of the glenoid cavity anteriorly or 33% or more of the glenoid cavity posteriorly and displacement of the fragment 10 mm or more
- Fossa fractures: an articular step-off of 5 mm or more, significant separation of the fracture fragments, or failure of the humeral head to lie in the center of the glenoid cavity

Preoperative Planning

Imaging studies should be reviewed before the surgery and should be available for reference in the operating room. A draped fluoroscopy unit and a competent technician should be available. An examination for instability can be performed while under anesthesia.

FIG 1 • Goss-Ideberg classification of glenoid cavity fractures. Ia, anterior rim; Ib, posterior rim; II, inferior glenoid; III, superior glenoid; IV, transverse through the body; V, combination of II to IV; VI, comminuted.

FIG 2 • A. The anteroposterior (AP) radiograph shows a type Vc glenoid cavity fracture. B. Axillary CT image shows a large anterosuperior glenoid cavity fragment including the coracoid process. (continued)

FIG 2 • (continued) C. Axillary CT image shows the lateral aspect of the scapular body lying between the two glenoid cavity fragments and abutting the humeral head. D. Axillary CT image shows a large posteroinferior cavity fragment. (From Goss TP, Owens BD. Fractures of the scapula: diagnosis and treatment. In: Iannotti JP, Williams GR, eds. Disorders of the Shoulder: Diagnosis and Management, ed 2. Philadelphia: Lippincott Williams & Wilkins, 2007:793-840.)

Positioning