The long bone on the upper extremity is the humerus and articulates with the scapula and clavicle forming a ball and socket shoulder joint. Distally, the humerus articulates with the radius and ulna forming a hinge elbow joint. It can be divided into three separate regions: proximal, shaft, and distal.
Focusing on the proximal anatomy of the humerus the main features include the head, anatomical neck, surgical neck, greater and lesser tubercles and intertubercular sulcus. The humeral head articulates with shallow glenoid fossa of the scapula which allows for greater range of motion. The anatomical neck can be identified as the fused epiphyseal plate which is obliquely directed and lies proximal to greater and lesser tubercles. The greater tubercle has three muscular attachment of the rotator cuff (supraspinatus, infraspinatus and teres minor) which is located laterally on the humerus. The lesser tubercle located lies more medially, smaller in size serves as an attachment for the last muscle of the rotator cuff (subscapularis). The intertubercular sulcus or groove separates the two tubercles. The tendon of the long head of biceps brachii runs through this groove. Attached to the lips of the intertubercular sulcus are the tendons of the pectoralis major, teres major, and latissimus dorsi. The most frequently fractured site of the humerus especially in elderly is the surgical neck which is an area of constriction distal to tubercles. Several neurovascular structures are at risk of damage including axillary nerve and posterior circumflex humeral artery.
Fall on an outstretched hand (FOOSH) is the most common mechanism of action. The amount of energy required varies by age group; low energy falls lead to fractures in the elderly due to osteoporotic bone. This is compared to the young patient where high energy trauma causes proximal humeral fractures with associated soft tissue and neurovascular injuries.
Proximal humerus fractures are the third most common fracture in elderly. Overall incidence is reported at 4% to 6% with a 2:1 female to male ratio.
Documentation of a proper history is important when patients present to be seen. Most cases present in the acute setting. Pertinent questions include a description of pain with related features such as site, onset, radiation, aggravating and relieving factors. The mechanism of injury, whether direct or indirect, should be noted.
Inspection is assessing for signs of open fracture, ecchymosis that may extend to the chest, arm, and forearm. Loss of deltoid contour suggests concomitant dislocation of shoulder suggesting a higher energy mechanism. Upon palpation with the aid of analgesics, fracture stability should be determined by both active and passive movements through the shoulder and elbow joint. There is a 45% incidence of nerve injury (axillary most common). However, the arterial injury may be difficult to ascertain due to extensive collateral circulation preserving distal pulses.
Completion of evaluation with radiographs should be performed after history and physical exam. Initial images from the complete trauma series include true AP, scapular Y, and axillary views. The other additional views which can be obtained are apical, oblique, Velpeau and West Point. The Velpeau view is performed with the patient's arm is held in internal rotation in a sling, and the film is taken superior to inferior with the patient leaning backward. Technique for West Point x-ray, the patient is placed prone on the x-ray table. The affected shoulder is raised at the top of the table and cassette held against the superior aspect of the shoulder. The x-ray beam is centered at axilla. A tangential view of the anteroinferior rim of the glenoid rim is the resulting image of the shoulder.
CT scan aids in preoperative planning especially if the position of the humeral head or greater tuberosity is uncertain and intra-articular comminution.
MRI is rarely indicated however may be useful to identify associated rotator cuff injury
Neer’s Classification is based on the anatomic relationship of four segments: greater tuberosity, lesser tuberosity, articular surface, and shaft.
AO Classification arranges fractures into three main groups and additional subgroups based on fracture location, the status of the surgical neck, and the presence or absence of dislocation.
Initial management includes immobilization and pain control in the acute setting. Goals of management can then be determined whether non-operative versus operative.
Nonoperative with sling immobilization followed by rehab starting as early as 14 days. This is indicated in 80% to 85% of proximal humerus fractures. These include minimally displaced surgical neck fractures (Neer’s one, two, and three-part), greater tuberosity fracture which is displaced less than 5 mm and patients who are not surgical candidates.
Operative management has several options including closed reduction and percutaneous pinning, open reduction and internal fixation, intramedullary nailing, hemiarthroplasty and total arthroplasty.
The indications for each procedure is detailed.
Closed reduction percutaneous pinning (CRPP): two-part, three-part surgical neck fractures and valgus-impacted four-part fractures in patients with good bone quality, minimal metaphyseal comminution, and intact medial calcar.
ORIF: Indicated for greater tuberosity displaced greater than 5 mm, two, three, and four-part fractures in younger patients and head-splitting fractures in younger patients.
Intramedullary rodding: surgical neck fractures or three-part greater tuberosity fractures in younger patients, combined proximal humerus, and humeral shaft fractures
Hemiarthroplasty: Anatomic neck fractures in elderly (initial varus malalignment greater than 20 degrees) or those that are severely comminuted, four-part fractures and fracture-dislocations (three-part if stable internal fixation unachievable), rotator cuff compromise, chronic nonunions or malunions in the elderly, head-splitting fractures with incongruity of humeral head, humeral head impression defect of greater than 40% of articular surface and detachment of articular blood supply (most three-part and four-part fractures).
Total shoulder arthroplasty: Performed when the rotator cuff is intact with a compromised glenoid surface (arthritis, trauma).
Reverse shoulder arthroplasty: Indicated in elderly individuals with non-reconstructible tuberosities.