Scapula Bone Fractures: Anatomy, Classification, Clinical Features and Treatment

Scapula fractures are uncommon and they only result from high energy trauma because scapula is in protected position
Common causes include:
- Direct blunt trauma
- Crush injuries
- Fall on the shoulder
- Seizures

Scapula anatomy

Scapula (aka shoulder blade) is a triangular flat bone located on the posterolateral aspect of the thorax
The posterior surface of scapula is divided by a thick ridge of a bone which is called the spine of scapula
It is divided into a smaller supraspinous fossa (origin of supraspinatus muscle) and a larger infraspinous fossa (origin of infraspinatus and teers minor muscles)
The spine of scapula continues laterally to form the acromion, acromion articulates with the acromial end of the clavicle and it is also a point of attachment to trapezius muscle
The anterior surface of scapula forms the subscapular fossa (origin of subscapular muscle
Superolateral of the scapula, there is the glenoid cavity, which articulate with the head of the humerus at the glenohumeral joint
Superior to the glenoid, there is the coracoid process which projects anterolaterally, it provide attachment to CC ligaments, and it is the origin of the short head of biceps and brachialis muscles

Patient arm is held immobile and there is severe bruising over the scapula and the chest wall due to the high energy injury sustained by that area
Patient complain of severe diffused shoulder pain, shortness of breath and chest wall pain
Evaluate and resuscitate patient based on ATLS trauma protocol
There is usually associated severe injuries to the chest, brachial plexus, spine, abdomen and head, look for them
Careful neurological and vascular examinations are essential

In addition to trauma labs and radiographs, send the patient for Scapula AP and Y views and shoulder axially view are the most helpful radiographs in detecting scapula fractures
But these fractures might be difficult to be seen on X ray due to surrounding soft tissues
CT scan are useful in detecting and classifying scapula fractures and detecting associated injuries

Scapular body fractures are described based on anatomical location
Most of these fractures are minimally displaced and treated non operatively with sling immobilization
Patient is advised to exercise the shoulder, elbow and fingers from the beginning to prevent stiffness

Fractures involving the glenoid fossa and rim are subclassified according Ideberg modified by Goss classification
This is the most commonly used classification to describe Glenoid fractures

Fracture involving the glenoid rim
Mostly minimally displaced and treated non operatively
If the fracture involve more than a 25% of the glenoid surface and is displaced by 5 mm then this is indication of surgical fixation of Type I fractures

Fracture through glenoid fossa
Inferior fragment significantly displaced, The attached long head of the triceps may drag the fractured glenoid downwards and laterally
Associated with humeral head subluxation => unstable shoulder joint
Treatment is with open reduction and internal fixation since shoulder joint is unstable

Oblique fracture through the glenoid exiting superiorly
Significant displacement
Maybe associated with AC joint dislocation
Treatment: If the humeral head is centered on the major portion of the glenoid and shoulder is stable then a non operative approach is taken but if not then treated operatively

Horizontal fracture exiting through the vertebral border of the scapula
Significant displacement
Treatment: If the humeral head is centered on the major portion of the glenoid and shoulder is stable then a non operative approach is taken but if not then treated operatively

Combination of type IV and another fracture separating the inferior part of the glenoid
Significant displacement
Treatment: If the humeral head is centered on the major portion of the glenoid and shoulder is stable then a non operative approach is taken but if not then treated operatively

Classified according to Kuhn acromial fracture classification, this classification include three types:
- Type I minimally displaced => treated non operatively
- Type II displaced but does not compromise the subacromial space => treated non operatively
- Type III displaced and compromises the subacromial space => treated operatively

Those classified according to Ogawa coracoid process fracture classification, it is on two types:
- Type I fracture occurs proximal to the coracoclavicular ligament => associated with AC joint separation => mostly treated operatively
- Type II fracture occurs distal to the coracoclavicular ligament => doesn’t hurt AC joint => treated non operatively

If there was a fracture involving the scapula + there is associated fracture of the clavicle or disruption of AC ligament => glenoid gets displaced => it is called “ the floating shoulder”

Disruption of the scapulothoracic articulation where the scapula is displaced by > 1 cm from the spinous processes in comparison with the contralateral side
It is caused by high energy trauma
Associated with severe neurovascular injuries and fractures

Post traumatic glenohumeral arthritis: high risk for this if it was intra articular glenoid fractures
Malunion
Recurrent glenohumeral instability
Neurovascular injury