6.1.1 Scapula
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1 Introduction
1.1 History
Fractures of the scapula have traditionally been treated without surgery. Nonunion of the scapula following fracture is extremely rare, and malunion was accepted with the expectation that most patients would have reasonable functional outcome with little or no pain. However, recent evidence has demonstrated that scapular malunion can be associated with significant functional disturbance, especially with greater degrees of deformity. This has prompted an increased interest in scapular fracture treatment including improved 3-D imaging, indications for surgery, fixation methods, and patient-related outcomes.
1.2 Epidemiology
Fractures of the scapula are relatively rare (0.4–1.0% of all fractures), usually seen in polytrauma patients, and are typically caused by severe force. For this reason, the patient must be carefully evaluated for other life-threatening injuries including flail chest, blunt aortic injury, hemothorax or pneumothorax, and lung contusion together with other fractures (especially of the clavicle, seen in 25% of cases) [1]. Isolated fractures are usually caused by a direct blow to the back and are typically stellate in nature. Fractures of the anterior or posterior glenoid rim are usually a result of glenohumeral dislocation or subluxation (“bony Bankart” lesions) [2], and the treatment focus is on restoring joint stability.
1.3 Special characteristics
The scapula is a complex bone that serves as an important origin for shoulder musculature and the scapulothoracic joint is integral to shoulder stability and motion. The bone in the scapular body is thin and most points for screw fixation are available around the borders of the scapula. Additionally, the scapula has a number of important processes (coracoid, acromion, scapular spine) that are important for shoulder function and also serve as potential sites for screw purchase. Goss [3] introduced the concept of the superior shoulder suspension complex to explain the biomechanics of some shoulder injuries.
2 Evaluation and diagnosis
2.1 Case history and physical examination
The clinical symptoms of a scapular fracture are nonspecific and frequently masked by the symptoms of concomitant injuries. Open fractures are rare. With a fracture of the scapular neck, the suprascapular nerve is at risk of being injured as it runs through the scapular notch at the superior border. Suspected lesions of this nerve have to be ruled out by an electromyogram. The same holds true for suspected lesions of the axillary nerve.
2.2 Imaging
The radiological examination consists of three trauma views of the shoulder (AP in scapular plane, lateral in scapular plane, and axillary projection). Involvement of the glenoid requires a computed tomographic (CT) scan to determine the number and size of the fragments as well as the extent of the articular displacement. Given the complexity of the scapula, 3-D CT reconstruction is becoming increasingly popular for preoperative planning. The clavicle should always be assessed as associated fractures are common.
3 Anatomy
The scapular body is broad and flat, thin in the middle area and thicker around the axillary and vertebral borders. The scapular spine is a prominent structure posteriorly and the best surgical access to the scapular body and spine is posterior. The deltoid muscle envelopes most of the superior aspect of the scapula and must be reflected or split, depending on the approach selected. The coracoid and acromion are separate processes that are best accessed through an anterior and superior approach, respectively.
4 Classification
4.1 AO/OTA Fracture and Dislocation Classification
The scapula is numbered bone 14 [4]. It is divided into the three locations process (14A), body (14B), and glenoid fossa (14F).
5 Surgical indications
Surgical indications remain controversial. Operative intervention is reserved for active healthy patients with low intrinsic operative risk. Older, sedentary patients with medical comorbidities are best treated nonoperatively. The indications listed are relative, not absolute, and the decision to proceed with surgery is made only after a careful evaluation of the risks and benefits for the individual patient.
Glenoid rim (anterior, inferior, or posterior) fracture with associated shoulder joint instability
Intraarticular joint displacement of 5 mm or greater involving more than 25% of the joint surface
Glenopolar angle < 22°
Medial displacement of glenoid neck fracture > 2 cm
100% displacement or > 45° angulation of a scapular body fracture
Completely displaced process fracture (acromion, coracoid, scapular spine)
Significant malangulation (retroversion or anteversion) of the scapular neck
Young polytrauma patient
Disrupted superior shoulder suspensory complex (two breaks in the ring)
6 Preoperative planning
6.1 Timing of surgery
Acute fixation of scapular fractures is rarely indicated and there is sufficient time for stabilization of the patient (especially in the polytrauma setting) and obtaining preoperative imaging. As with any fracture surgery, success depends on careful planning, a medically optimized patient and robust soft-tissue coverage of the anticipated fracture fixation. Soft-tissue coverage is rarely an issue. It is now “standard of care” that imaging includes preoperative CT scanning (with 3-D reconstruction if available) to plan surgical fixation. Glenoid/scapular fracture surgery is a difficult procedure on an irregular, complex bone that should be carried out in optimal conditions, ie, a stable patient, thorough preoperative imaging and planning, and skillful surgery performed on a carefully positioned patient by a well-rested, experienced surgeon with a variety of potential implants handled by orthopedic surgical support staff.
6.2 Implant selection
In general, small or mini-fragment implants are used for scapular and glenoid fixation. Glenoid rim fractures are stabilized with partially threaded 4.0 mm cancellous screws. Fractures of the scapular body are treated with 1/3 tubular plates or reconstruction plate 3.5. Compression plates are too bulky and the added strength is not required in this setting. Typically, except along the borders, the scapular body is thin and will accept screws of only 12–14 mm. Fractures of the acromion, acromial spine, or coracoid can be managed with mini-fragment plates and 2.7 mm screws. Precontoured plates designed for the scapula and its processes are available and may decrease the amount of time required for placement and contouring intraoperatively.
6.3 Operating room set-up
The area from the neck to the hand, including the axilla, is disinfected with the appropriate antiseptic. Draping should be done in such a way as to leave the posterior aspect of the arm exposed from shoulder to elbow. Then the hand and forearm are draped separately with a stockinette fixed properly to the forearm ( Fig 6.1.1-1a ). The image intensifier is also draped.
The anesthetist and anesthetic equipment are situated to the side of the patient. The surgeon and assistant stand on the side of the injury. The operating room personnel stand between (behind) the surgeons. When required, the image intensifier is introduced from the top of the operating room table. The image intensifier display screen is placed in full view of the surgical team and the radiographer ( Fig 6.1.1-1b ).
7 Surgery
7.1 Surgical approaches
There are a number of surgical approaches to the scapula, and the choice of approach will depend on the fracture pattern and the fractures specifically targeted for fixation. Many scapular fracture patterns are complex and it is not always necessary to stabilize every fracture line. The risks and drawbacks of added operative time and soft-tissue disruption must be balanced against the added reduction or stability gained by further fixation.
7.1.1 Deltopectoral approach
This approach is used for fractures of the anterior and inferior glenoid rim. Following reflection of the subscapularis and an anterior arthrotomy, the humeral head can be subluxated posteriorly to visualize the anterior glenoid rim. Since the stability of the joint is restored after fixation of the fragment, the capsule is closed anatomically and the transected or split subscapularis tendon is meticulously sutured to avoid any weakness and limitation of shoulder motion. This approach may also be used to expose and fix associated coracoid fractures. However, it does not provide adequate exposure for most glenoid neck or body fractures.
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