Humerus fracture (Distal 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.

1. 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)
   • Commonly used classification (Neer) is based on whether one or more of these four segments have been displaced^[1]
   • Neer classification
     • Group I: minimal fragment displacement
     • Group II: displaced fragment at anatomical neck
     • Group III: fracture at surgical neck (= subcapital fracture)
     • Group IV: greater tuberosity avulsion fracture
     • Group V: avulsion fracture of lesser tuberosity
     • Group VI: fracture dislocation
2. Humeral shaft fracture
   • Classified according to location: proximal third, middle third (most common location), distal third^[2]
   • Or according to comminution: type A (no comminution), type B (butterfly fragment), and type C (comminution is present)^[1]
3. Distal humerus fracture
   • Classification according to anatomical site
     • Lateral/medial fractures
     • Supracondylar fractures; (supracondylar fractures are the most common pediatric elbow fracture )^[3]
   • classification
     • Type A (extra‑articular fractures): supracondylar fracture
     • Type B (unicondylar fractures)
     • Type C (bicondylar fractures)

• Severe local pain: exacerbated during palpation or movement at shoulder or elbow^[1]
• Local swelling (edema or bleeding), deformity, or crepitus^[1]
• Shortening of the arm (associated with displacement)^[1]
• Also see signs of fracture
• Neurovascular complications may be present^[1]

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!references: ^[1]

• X-ray (AP and lateral views of the humerus as well as transthoracic and axillary views of the shoulder)^{[2] [1]}
  • Radiographic features of fractures
  • A supracondylar fracture may also reveal:^[4]
    • Positive posterior fat pad sign (not normally visible)
    • Sail sign: positive anterior fat pad sign (normally visible, but not elevated )
• CT if x-ray is not diagnostic^[1]
• MRI if pathological fracture is suspected

Conservative therapy

• Indication: nondisplaced, closed fractures^{[1] [4]}
• Procedures
  • Hanging-arm cast or coaptation splint and sling^[3] for approx. one to two weeks; subsequent follow‑up X‑ray and brace^[1]
  • Early physical therapy to restore function^[1]

Surgical treatment

• Indication: open fractures, displaced fractures that cannot be reduced, associated injuries (nerves, blood vessels), floating elbow (simultaneous humerus and forearm fracture), pseudarthrosis^[2]
• Procedures
  • Internal fixation; using plates and screws, or intramedullary implants (especially supracondylar fractures)^{[1] [5] [2]}
  • External fixation (e.g., open fracture, polytrauma)^[5]
  • Arthroplasty of humeral head or elbow (complex fractures or poor quality bone), especially in elderly patients^[1]

Open fractures require irrigation and prophylactic antibiotic therapy!references: ^[1]

• Proximal humerus fracture^[1]
  • Adhesive capsulitis
  • Avascular necrosis of humeral head (axillary artery injury)
  • Heterotropic bone formation
• Humeral shaft fracture:^[1] Radial nerve palsy (common)
• Distal humerus fracture^[4]
  • Malunion and varus deformity of elbow
  • Brachial artery injury (common)
    • Absent radial pulse suggests brachial artery entrapment (especially following reduction!) and compartment syndrome
    • → Volkmann's ischemic contracture (late complication)
  • Median nerve, ulnar nerve, or radial nerve palsy

Humerus fracture nerve palsies
Nerve	Clinical features[6]
Axillary	Flat deltoid ↓ Arm abduction at shoulder > 15 degrees ↓ Sensation over deltoid and lateral arm
Radial	Wrist drop ↓ Grip strength, ↓ Sensation over dorsal hand and posterior arm
Ulnar	“Ulnar claw” ↓ Wrist flexion of medial fingers, abduction and adduction of fingers ↓ Sensation over medial 1 ½ fingers (5th digit and half of the 4th digit) including hypothenar eminence Radial deviation when wrist is flexed
Median	Unable to oppose index finger and thumb of affected hand Tinel sign ↓ Wrist flexion, lateral finger flexion, and thumb opposition ↓ Sensation over thenar eminence and over lateral 3½ fingers (first 3½ digits, beginning with the thumb)

• Also see complications of fractures

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