Humerus fracture

Humerus fractures can result from direct or indirect trauma. They are classified according to their location as proximal, humeral shaft, or distal fractures. Proximal humerus fractures commonly occur in the elderly, while distal supracondylar fractures are the most common type of fracture in the pediatric population. Patients may present with localized pain, swelling, and deformities. Conservative treatment (splinting, casting, and physical therapy) often suffices for nondisplaced, closed fractures. While arteriovenous complications and displaced or open fractures usually require surgical treatment.

• Proximal humerus fracture (common in the elderly)
  • The proximal humerus has four major segments: the anatomical neck, the humeral shaft, the greater tuberosity, and the lesser tuberosity (the surgical neck is distal to the lesser and greater tuberosity)
  • Neer classification: a commonly used classification that is based on whether one or more of these four segments have been displaced ^[2]
    • One-part fracture: fracture lines involve 1–4 parts but no are fragments displaced
    • Two-part fracture: fracture lines involve 2–4 parts and 1 part is displaced
    • Three-part fracture: fracture lines involve 3–4 parts and 2 parts are displaced
    • Four-part fracture: fracture lines involve 4 parts and 3 parts are displaced
• Humeral shaft fracture
  • Classification according to location: proximal third, middle third (most common location), distal third
  • Classification according to comminution: type A (no comminution), type B (butterfly fragment), and type C (comminution is present)
• Distal humerus fracture
  • Classification according to anatomical site
    • Lateral/medial fractures
    • Supracondylar fractures: a fracture of the distal humerus, superior to the elbow joint
      • Typically a transverse fracture above the medial and lateral epicondyles
      • The most common pediatric elbow fracture ^[3]
  • AO classification ^[4]
    • Type A: extra‑articular fracture
    • Type B: partial articular
    • Type C: complete articular fracture

• Severe local pain: exacerbated during palpation or movement at shoulder or elbow
• Local swelling (edema or bleeding), deformity, and/or crepitus
• Shortening of the arm (associated with displacement)
• Neurovascular complications such as radial nerve palsy (see “Complications” below)
• See “Signs of fracture.”

The radial nerve runs through the radial sulcus of the upper arm and is especially at risk in fractures of the middle third (midshaft) of the humerus!

• X-ray (AP and lateral views of the humerus as well as transthoracic and axillary views of the shoulder)
  • Radiographic features of fractures
  • In the case of supracondylar fracture: possibly positive fat pad sign
    • Represent elbow joint effusion and may indicate an occult fracture
    • Can be seen on a lateral view of the elbow joint in which the joint is flexed at ∼ 90°
    • Posterior fat pad sign: a radiographic sign characterized by the presence of a lucent crescent in the olecranon fossa (can also be positive in radial head fractures)
    • Anterior fat pad sign (sail sign): a radiographic sign characterized by the presence of a lucent crescent in the coroid fossa
  • In the case of pathological fractures: signs of other entity (e.g., cysts, tumor)
• CT: if x-ray is not diagnostic
• MRI: if pathological fracture is suspected and/or to evaluate rotator cuff injury

Conservative therapy

• Indication: nondisplaced, closed fractures
• Procedures
  • Hanging-arm cast or coaptation splint and sling for approx. one to two weeks with subsequent follow‑up x‑ray and brace
  • Early physical therapy to restore function

Surgical treatment

• Indication: open fractures, displaced fractures that cannot be reduced, associated injuries (nerves, blood vessels), floating elbow (simultaneous humerus and forearm fracture), pseudarthrosis
• Procedures
  • Internal fixation using plates and screws, or intramedullary implants (especially supracondylar fractures)
  • External fixation (e.g., open fracture, polytrauma)
  • Arthroplasty of humeral head or elbow (e.g., in complex fractures), especially in elderly patients

Open fractures require irrigation and prophylactic antibiotic therapy.

• Proximal humerus fracture
  • Adhesive capsulitis
  • Avascular necrosis of humeral head (axillary artery injury)
  • Heterotopic bone formation
• Distal humerus fracture
  • Malunion and varus deformity of elbow
  • Brachial artery injury (common)
    • Absent radial pulse suggests brachial artery entrapment (especially following reduction) and compartment syndrome
    • May lead to Volkmann ischemic contracture (late complication)

Humerus fracture nerve palsies
Nerve	Motor function	Sensory function	Associated site of humerus fracture
Axillary	Flat deltoid ↓ Arm abduction at shoulder > 15 degrees	↓ Sensation over deltoid and lateral arm	Proximal humerus
Radial	Wrist drop ↓ Grip strength	↓ Sensation over dorsal hand and posterior arm	Humeral shaft Distal humerus
Ulnar	Claw hand deformity Froment sign Radial deviation when wrist is flexed	↓ Sensation over medial 1 ½ fingers (5th digit and half of the 4th digit) including hypothenar eminence	Distal humerus
Median	Anterior interosseous nerve syndrome: unable to oppose index finger and thumb of affected hand ↓ Wrist flexion ↓ Flexion of lateral fingers and ↓ thumb opposition	↓ Sensation over thenar eminence and over lateral 3½ fingers (first 3½ digits, beginning with the thumb)	Distal humerus

• See “Peripheral nerve injuries in the upper extremity“ and “Complications of fractures.”

“Broken ARM:“ Axillary, Radial, and Median nerves can be injured.

Injuries to the median nerve and brachial artery, which both cross the elbow, are common complications of supracondylar fractures.

We list the most important complications. The selection is not exhaustive.