The proximal humerus is composed of the head (articular surface), the lesser and greater tuberosities, and the surgical neck.
The lesser tuberosity is the attachment for the subscapularis, which can lead to medial fragment displacement in multipart proximal humeral fractures. The greater tuberosity is where the supra- and infraspinatus muscles insert; superior and posterior displacement of this fragment is not uncommon.
The height of the greater tuberosity is important to recreate accurately. It is approximately 5.6 mm above the pectoralis major tendon insertion.
The glenohumeral joint is extremely mobile and can lead to confusing imaging.
The scapula is typically internally rotated 20 to 30 degrees. The humeral head is also retroverted approximately 30 degrees relative to the elbow joint axis.
AP Shoulder View
The standard AP view of the shoulder is in fact an AP view of the ipsilateral chest wall.
This view allows good visualization of the proximal humeral neck and shaft.
Because the proximal humerus is internally rotated relative to the arm, the greater tuberosity is visualized en face, and this can highlight the typically posterior and superior displacement.
The standard AP view also allows for a linear view of the acromioclavicular joint (Fig. 4-1).
Grashey or True AP View
This view best demonstrates the profile of the glenohumeral joint. It is performed with the fluoroscopic beam in 30 degrees of internal rotation in order to match the position of the scapula/glenoid.
The congruity of the humeral head can also be better appreciated on this view along with the restoration of the medial calcar.
Performing this view in 30 to 40 degrees of abduction will help recreate normal anatomy.
On final fluoroscopic films, the lengths of screws, and especially the proximal screws, should be checked to ensure iatrogenic perforation has not occurred (Fig. 4-2).
The image is obtained by shooting through the axilla with the shoulder in neutral flexion and 30 to 90 degrees of abduction.
This view is rarely useful until most of the reduction has been completed. It allows the surgeon to ensure that (Fig. 4-3):
The glenohumeral joint is concentric.
The lesser tuberosity is reduced.
The greater tuberosity is reduced.
Sagittal plane reduction of the humeral neck has been achieved.
Humeral head retroversion has been restored.
The plate is appropriately located on the proximal humerus.
The screw lengths and trajectories are appropriate.
Preoperative imaging for all proximal humerus fractures should include AP, Grashey, and an axillary view.
Indications for surgery include displaced three and four part fractures, severely displaced two-part fractures in active patients, head split–type fractures, and any irreducible fracture dislocation.
Often, a CT scan is useful in assessing the fracture pattern. A head split may be difficult to discern on the plain films, but becomes obvious on CT scan. Also, the extent and displacement of tuberosity comminution can be quantified prior to surgery. Finally, the concentricity of the glenohumeral joint can be appreciated if a preoperative axillary view was not done or unclear.
Operative treatment of proximal humerus fractures can be achieved in several ways. Most commonly open reduction and internal fixation is performed; however, in some cases the humerus is unrepairable and arthroplasty is necessary. Some authors have also started advocating newer humeral nailing systems with numerous interlocking options.
If internal fixation is chosen, this can be achieved through two different operative approaches (deltopectoral and deltoid splitting).
Open reduction and internal fixation can be performed in either the supine or beach chair positions. Arthroplasty is typically done in the beach chair position.
Therefore, fractures that may not be amenable to fixation should be placed in the beach chair position if an intraoperative decision to perform arthroplasty is taken.
Advantages to the supine position include easier fluoroscopic imaging and avoidance of cerebral hypotension issues associated with beach chair position.
Another advantage of the supine position is it can be used in the polytrauma patient for multiple site fracture fixation (i.e., simultaneous upper and lower extremity fractures).
The beach chair position is more versatile, and surgeons should be familiar with optimal positioning if required.
1. Supine Position
This position should be used for ORIF as mentioned. Optimal position can allow for easier imaging and subsequently more efficient surgery.
A radiolucent table should be used with the head elevated slightly (20 to 30 degrees).
The patient should be moved over completely to the operative side so that the head is flush with the proximal corner of the table.
It is important to fix the patients head in this position, because it may shift during surgery, especially with longitudinal traction of the arm, which is often necessary for reduction.
A padded radiolucent board (i.e., Plexiglas with blankets) approximately 8 to 12 inches in width can be placed underneath to support the arm. This ensures clear imaging by eliminating the table side, which can sometimes interfere with fluoroscopy.
The uninjured side can be padded and placed on the operative table safely.
The table is rotated 90 degrees into the room, and the C-arm is brought in from the head and preoperative fluoroscopy is done to ensure proper positioning (Fig. 4-4).
Alternatively, the C-arm can be brought in from the opposite side in the polytrauma context where multiple fracture sites will be operated on (Fig. 4-5).
The AP view is achieved by shooting with a perpendicular beam, which require some rollover (cranial tilt) to match the tilt of the table.
The Grashey view is then obtained in the same fashion but by adding 30 degrees of lateral tilt to match scapular rotation.
Finally, the axillary view is produced with the C-arm rolled back parallel with the patient in both planes. Sometimes a small amount of internal rotation and abduction of the beam is necessary to clear the head adequately.