Mechanisms of injury• The body of the scapula is fractured by a crushing force, which usually also fractures ribs and may dislocate the sternoclavicular joint.• The neck of the scapula may be fractured by a blow or by a fall on the shoulder; the attached long head of triceps may drag the glenoid downwards and laterally.• The coracoid process may fracture across its base or be avulsed at the tip.• Fracture of the acromion is due to direct force.• Fracture of the glenoid fossa usually suggests a medially directed force (impaction of the joint) but may occur with dislocation of the shoulder.
Clinical features• The arm is held immobile and there may be severe bruising over the scapula or the chest wall.• Because of the energy required to damage the scapula, fractures of the body of the scapula are often associated with severe injuries to the chest, brachial plexus, spine, abdomen and head.• Careful neurological and vascular examinations are essential.
X-Ray• Scapular fractures can be difficult to define on plain x-rays because of the surrounding soft tissues.• The films may reveal a comminuted fracture of the body of the scapula, or a fractured scapular neck with the outer fragment pulled downwards by the weight of the arm.• Occasionally a crack is seen in the acromion or the coracoid process.• CT is useful for demonstrating glenoid fractures or body fractures.
Classification• Fractures of the scapula are divided anatomically into scapular body, glenoid neck, glenoid fossa, acromion and coracoid processes.• Scapular neck fractures are the most common.• Further subdivisions are shown in Table 24.1.
Treatment• Body fractures• Surgery is not necessary. The patient wears a sling for comfort, and from the start practices active exercises to the shoulder, elbow and fingers.• Isolated glenoid neck fractures• The fracture is usually impacted and the glenoid surface is intact. A sling is worn for comfort and early exercises are begun.
• Intra-articular fractures• Type I glenoid fractures, if displaced, may result in instability of the shoulder.• If the fragment involves more than a third of the glenoid surface and is displaced by more than 5 mm surgical fixation should be considered.• Anterior rim fractures are approached through a delto-pectoral incision and posterior rim fractures through the posterior approach.• Type II fractures are associated with inferior subluxation of the head of the humerus and require open reduction and internal fixation.
• Types III, IV, V and VI fractures have poorly defined indications for surgery.• Generally speaking, if the head is centred on the major portion of the glenoid and the shoulder is stable a non-operative approach is adopted.• Comminuted fractures of the glenoid fossa are likely to lead to osteoarthritis in the longer term.
• Fractures of the acromion• Undisplaced fractures are treated non- operatively.• Only Type III acromial fractures, in which the subacromial space is reduced, require operative intervention to restore the anatomy.
• Fractures of the coracoid process• Fractures distal to the coracoacromial ligaments do not result in serious anatomical displacement; those proximal to the ligaments are usually associated with acromioclavicular separations and may need operative treatment.
• Combined fractures• Whereas an isolated fracture of the glenoid neck is stable, if there is an associated fracture of the clavicle or disruption of the acromioclavicular ligament the glenoid mass may become markedly displaced giving rise to a ‘floating shoulder’ (Williams et al, 2001).
• Diagnosis can be difficult and may require advanced imaging and three-dimensional reconstructions.• At least one of the injuries (and sometimes both) will need operative fixation before the fragments are stabilized.
SCAPULOTHORACIC DISSOCIATION• This is a high energy injury.• The scapula and arm are wrenched away from the chest, rupturing the subclavian vessels and brachial plexus.• Many patients die.
Clinical features• The limb is flail and ischaemic.• The diagnosis is usually made on the chest x-ray.• There is swelling above the clavicle from an expanding haematoma.• A distraction of more than 1 cm of a fractured clavicle should give rise to suspicion of this injury.
Treatment• The patient is resuscitated.• The outcome for the upper limb is very poor.• Neither vascular reconstruction nor brachial plexus exploration and repair are likely to give a functional limb.