Causes / typical injury mechanism: Proximal humerus fractures most commonly occur in the elderly population, typically from ground level falls in the setting of osteoporosis or osteopenia. However, these fractures can also occur in younger patients from high-energy impacts.

Classic history and presentation: An elderly patient presenting with arm pain after a ground level fall on an outstretched arm in an attempt to brace themselves.

Prevalence: Accounts for 5%-6% of all adult fractures.

• Age – most common in patients older than 65 years
• Sex / gender – 2:1 female-to-male ratio

Risk factors: History of osteoporosis or osteopenia.

Pathophysiology: Osseous components of the proximal humerus become fractured or displaced, usually secondary to direct trauma. Traditionally, proximal humerus fractures have been classified by their component fractured parts: humeral shaft, humeral head, greater tuberosity, and lesser tuberosity.

Grade / classification system:
Neer Classification
In order to be classified as a fractured part, the fractured component needs to either be displaced greater than 1 cm or have angulation exceeding 45 degrees. The exception is the greater tuberosity, which is considered displaced at 5 mm.

• One-Part Fracture
  • Fracture involves 1-4 parts
  • No parts are displaced
• Two-Part Fracture
  • Fracture involves 2-4 parts
  • One part is displaced
• Three-Part Fracture
  • Fracture involves 3-4 parts
  • Two parts are displaced
• Four-Part Fracture
  • Fracture involves more than 4 parts
  • Three parts are displaced