Fracture of the Proximal Humerus

The Injury and the Neer Classification

Fractures of the proximal humerus are common in the elderly osteoporotic patient after a fall on the outstretched hand, and in younger patients after high-energy trauma. They are classified by NEER, which divides the proximal humerus into four anatomical 'parts' — the humeral head (articular segment), the greater tuberosity, the lesser tuberosity and the shaft. A 'part' counts as displaced only when it is separated by more than 1 cm OR angulated more than 45°. The fracture is then described as one-, two-, three- or four-part, which reflects both the severity and the risk to the head's blood supply.

Clinical Features and Assessment

There is pain, swelling and bruising (which characteristically tracks down the arm and chest wall a few days later), with restricted, painful shoulder movement. The axillary nerve must be tested (regimental-badge sensation), as it is at risk. Imaging is with an AP and an axillary or scapular-Y view (CT for complex patterns).

Management

The majority are minimally displaced (one-part) and are treated conservatively — a collar-and-cuff or sling, with early pendulum exercises within 1–2 weeks to prevent a stiff shoulder. Displaced two- and three-part fractures are often treated by internal fixation (locking plate or intramedullary nail). Four-part fractures and head-splitting fractures in the elderly, in which the head's blood supply is lost, are treated by arthroplasty (hemiarthroplasty or reverse total shoulder replacement).

Complications

Avascular necrosis of the humeral head is the most important — its risk rises with the number of parts (highest in four-part and head-splitting fractures), because the anterior circumflex humeral artery and its ascending branch, which supply the head, are torn. Shoulder stiffness is the commonest problem overall and is why early pendulum exercises matter. Others are malunion (especially of the greater tuberosity, causing impingement), axillary-nerve injury, and non-union.

Most are minimally displaced and treated conservatively.

• Common in elderly osteoporotic patients after a FOOSH; test the axillary nerve.
• NEER classification uses four parts — head, greater tuberosity, lesser tuberosity, shaft — a part being 'displaced' if >1 cm apart or >45° angulated.
• Most are minimally displaced (one-part) → conservative (sling + early pendulum exercises to avoid stiffness).
• Displaced 2/3-part → internal fixation (locking plate/nail); 4-part or head-splitting in the elderly → arthroplasty.