Scapula fractures

The scapula is wrapped in muscle and sits on the chest wall, so it breaks only with high energy and rarely alone: rib fractures, pneumothorax, pulmonary contusion, head, spine and brachial plexus injuries are found in most patients. Body fractures are the commonest and usually heal well; what matters is whether the glenoid (articular surface) or the glenoid neck is displaced and whether the shoulder still hangs from an intact suspensory complex.

Mechanism

Direct blow or fall onto the shoulder in high-energy trauma (road traffic, falls from height). Axial load through the arm drives the humeral head into the glenoid (glenoid fossa fractures); anterior dislocation shears off the anteroinferior rim (bony Bankart).

Clinical findings

• Pain and bruising over the back of the shoulder, arm held adducted; often masked by other injuries in polytrauma.
• Primary survey first: chest injuries are the main threat. Examine the axillary and suprascapular nerves and the whole brachial plexus, and the distal pulses.
• Severe swelling over the scapula with a pale, pulseless arm: think of scapulothoracic dissociation (lateral displacement of the scapula, vascular and plexus injury).

Imaging

• Trauma chest X-ray or CT (most scapular fractures are found here; look for rib fractures and pneumothorax).
• Shoulder trauma series: true AP (Grashey), scapular Y view and axillary view.
• CT with 3D reconstructions (humerus subtracted): glenoid involvement, medialisation of the lateral border, angulation and glenopolar angle.

• Often first seen on the trauma chest X-ray or CT. True AP (Grashey), scapular Y and axillary views of the shoulder.
• CT with 3D reconstructions (humerus subtracted) is the standard to classify glenoid involvement and to measure medialisation of the lateral border, angular deformity on the Y view and the glenopolar angle (normal about 30–45°).

Classification

14A

Process fractures: A1 coracoid, A2 acromion.

14B

Body: B1 the fracture exits the body at two points or fewer, B2 at three or more.

14F

Glenoid fossa: F0 extra-articular glenoid neck, F1 simple articular, F2 multifragmentary articular.

Ideberg (Goss)

Glenoid fossa: Ia anterior rim, Ib posterior rim, II exits the lateral border, III exits superiorly, IV exits the medial border, V combinations of II–IV, VI severe comminution.

Floating shoulder (Goss)

Double disruption of the superior shoulder suspensory complex (glenoid, coracoid, coracoclavicular ligaments, distal clavicle, AC joint, acromion): classically a glenoid neck fracture with an ipsilateral clavicle fracture.

Types shown in 3D

14B1 body

Fracture across the body, exiting at the lateral and medial borders. The inferior fragment shifts laterally and forwards under the pull of teres major and serratus anterior. Almost always treated without surgery.

14F0 glenoid neck

Extra-articular: the glenoid is separated from the body lateral to the coracoid base and drops medially and inferiorly with the weight of the arm. With a clavicle fracture or AC disruption it becomes a floating shoulder.

Ideberg Ia

Anterior glenoid rim fracture (bony Bankart), usually from an anterior dislocation. The fragment goes anteriorly and medially with the capsule and labrum; a large fragment leaves the head unstable and is fixed.

14A2 acromion

Acromion fracture, here at its base. The deltoid tilts the fragment downwards into the subacromial space. Displaced fractures and those that are part of a double disruption are fixed.

14A1 coracoid

Coracoid fracture: the conjoint tendon (short head of biceps, coracobrachialis) and pectoralis minor pull tip fractures (Ogawa II) down and medially. Base fractures, behind the coracoclavicular ligaments (Ogawa I), leave the fragment tied to the clavicle and disrupt the suspensory complex.

Treatment

Non-operative (most)

Sling for comfort for 1–2 weeks, then early pendulum and assisted motion. Body fractures, minimally displaced neck fractures and most process fractures heal reliably with good function.

Extra-articular (body, neck)

Fixation is considered for marked displacement: lateral border medialised more than about 20 mm, angulation over 45° on the Y view, glenopolar angle under about 22°, or a combination of lesser values. Posterior Judet or modified (muscle-sparing) approach between infraspinatus and teres minor; plates along the lateral border and the spine.

Glenoid fossa

Fixation for an articular step or gap of more than about 3–5 mm, or a rim fragment large enough to leave the humeral head unstable (anterior rim fragments over roughly a fifth of the glenoid width). Anterior rim: deltopectoral approach or arthroscopic screw or suture fixation; posterior and complex patterns: posterior approach.

Processes and floating shoulder

Displaced acromion fractures (painful non-union, impingement) and coracoid fractures that are part of a double disruption: screws or plate. Floating shoulder: fixing the clavicle usually realigns the glenoid neck; fix the scapula too if it stays displaced.

Aftercare

Early passive motion; active motion from about 4–6 weeks; strengthening once united (usually 6–8 weeks for the body).

Complications

• Missed associated chest, head and spinal injuries
• Suprascapular nerve injury (fractures through the notch or spinoglenoid region)
• Shoulder stiffness and weakness after malunion
• Post-traumatic glenohumeral arthritis
• Acromial non-union