Fractures of Proximal Humerus

Majority of the proximal humeral fractures occur in older patients. This is so because older patients have osteopenic or osteoporotic bones which get damaged easily by trivial trauma. High energy trauma can produce these fractures in any person of any age.

Mechanism
Most of these fractures occur due to a simple fall on the arm.  Strong muscular contraction might be responsible in the setting of electric shock or seizure.

Most fractures are believed to result from indirect violence.

Muscle forces contribute to their displacement. Pectoralis major draws the shaft anteriorly and medially. The greater tuberosity may be pulled posteriorly by the infraspinatus and superiorly by the supraspinatus. The subscapularis tends to rotates internally a head segment where lesser tuberosity remains attached.

Clinical Presentation

Most patients with acute fractures of the proximal humerus present with a painful, swollen arm.  There could be bruises over the injured area or they might develop over a period.

Apart from the injured area that patient has presented with, the patient should be assessed for neck and chest injury. It goes without saying that distal limb should be examined for any neurovascular involvement.

The most commonly injured nerve is the axillary.

If the patient has amnesia, bilateral injuries, or a posterior fracture-dislocation, a seizure disorder or electric shock must be ruled out.

Radiography

The ordered radiographs for these fractures must include anteroposterior (AP) view of the scapula, a lateral “Y-view” of the scapula, and an axillary view.

If a good radiograph fails to detect anything  CT scans are most helpful in checking for dislocations, in ruling out a glenoid fracture, and in assessing posterior retraction of the greater tuberosity.

Classification

Most commonly used classification method is that of Neer’s. Fractures are classified by evaluating displacement of any of the four principal fragments (head, shaft, greater tuberosity, and lesser tuberosity).

All fractures in which no segment is displaced more than 1 cm or is rotated more than 45 degrees are considered minimally displaced and are considered together as one-part fractures, regardless of the number or location of fracture lines.

A single segment is displaced in a two-part fracture. This occurs most commonly with surgical neck displacement, in which the shaft is separated from the head and both attached tuberosities. It is also seen seen with greater tuberosity displacement.

A fracture with three-part displacement has the shaft and either the greater (most often) or lesser (rarely) tuberosity separated from the head, to which one of the tuberosities remains attached.

A four-part fracture is present when the head is separated from all other segments, even if the tuberosities are together (thus, there can be three pieces, one of which comprises both tuberosities). The head is completely dislocated out of the glenoid and is devoid of any soft tissue attachment. In the “valgus-impacted” four-part fracture, the head is rotated to face upward Although the head is completely out of contact with the glenoid.

If the head is split or has suffered an impression fracture, it is considered to have articular loss.

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