Classic history and presentation / risk factors: Twenty-eight percent of scapula fractures are sustained during motor vehicle accidents, 25% during motorcycle accidents, and falls account for 18% of cases, especially in geriatric populations.
Given the high-energy nature of scapular fractures, approximately 90% of patients will have a concomitant injury. About half of patients experience some form of ipsilateral upper extremity injury, thoracic injuries occur 80% of the time, and injuries to the head and spine are seen in 48% and 26% of patients, respectively. Sixty-four percent of patients will have rib fractures, with potentially associated pulmonary complications.
Prevalence: Scapula fractures are relatively uncommon, accounting for just 0.5% of all fractures. However, rates of diagnosis have increased with a growing geriatric population and associated fragility fractures, increased CT scan utilization, and improved emergency / trauma evaluation processes.
Patients are 78% male and 75% White. The most common ages at injury are between 20 and 60 years. Increasing rates of diagnosis have been seen among patients older than 60 years.
Pathophysiology / mechanism: Various mechanisms have been identified for each fracture pattern. A glenoid rim fracture can result from a fall on an outstretched hand or a shoulder dislocation. A scapular body or glenoid neck fracture may occur with direct, high-energy trauma. Avulsion fractures of the coracoid or acromion typically result from traction mechanisms. Intra-articular glenoid fractures can occur when the humeral head is driven into the glenoid fossa with great force.
Scapular fractures can be classified based on anatomical location:
- Intra-articular – Glenoid fractures.
- Extra-articular – Scapular neck / scapular body fractures (most common, 50% of all scapular fractures), coracoid fractures, and acromial fractures.
- Floating shoulder – Rare, this usually requires at least 2 fractures to the superior shoulder suspensory complex, such as a fractured scapular neck and ipsilateral clavicle. These injuries are typically associated with neurovascular compromise, including brachial plexus injuries.