Proximal Humerus Fractures

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• Overview

• proximal humerus fractures are common fractures often seen in older patients with osteoporotic bone following a simple ground-level fall on an outstretched arm.
• sling immobilization is the treatment for the majority of these fractures.
• surgical treatment may be indicated in more complex and displaced fractures.

• Epidemiology

• incidence
• 4-6% of all fractures
• third most common non-vertebral fracture pattern seen in the elderly (>65 years old)
• two-part surgical neck fractures are most common
• demographics
• 2:1 female to male ratio
• increasing age associated with more complex fracture types
• location
• may occur at the surgical neck, anatomic neck, greater tuberosity, and lesser tuberosity
• Risk factors
• osteoporosis
• diabetes
• epilepsy
• female gender

• Pathophysiology

• mechanism
• low-energy falls
• elderly with osteoporotic bone
• high-energy trauma
• young individuals
• concomitant soft tissue and neurovascular injuries
• pathoanatomy
• vascularity of articular segment is more likely to be preserved if ≥ 8mm of calcar is attached to articular segment
• predictors of humeral head ischemia (Hertel criteria)
• <8 mm of calcar length attached to articular segment
• disrupted medial hinge
• increasing fracture complexity
• displacement >10mm
• angulation >45°
• predictors of humeral head ischemia does not necessarily predict subsequent avascular necrosis

• Associated conditions

• nerve injury
• axillary nerve injury most common
• arterial injury
• uncommon (incidence 5-6%), higher likelihood in older patients
• most often occur at level of surgical neck or with subcoracoid dislocation of the head

• Symptoms

• pain and swelling
• decreased motion
• Physical exam
• inspection
• extensive ecchymosis of chest, arm, and forearm
• neurovascular exam
• axillary nerve injury most common
• determine function of deltoid muscle and lateral shoulder sensation
• arterial injury may be masked by extensive collateral circulation preserving distal pulses
• examine for concomitant chest wall injuries

• Radiographs

• recommended views
• complete trauma series
• true AP (Grashey)
• scapular Y
• axillary
• additional views
• apical oblique
• Velpeau
• West Point axillary
• findings
• combined cortical thickness (medial + lateral thickness >4 mm)
• studies suggest correlation with increased lateral plate pullout strength
• pseudosubluxation (inferior humeral head subluxation) caused by blood in the capsule and muscular atony

• CT scan

• indications
• preoperative planning
• humeral head or greater tuberosity position uncertain
• intra-articular comminution
• concern for head-split fracture
• MRI
• indications
• rarely indicated
• useful to identify associated rotator cuff injury

Treatment:

• Nonoperative
• sling immobilization followed by progressive rehabilitation
• indications
• most proximal humerus fractures can be treated nonoperatively including
• minimally displaced surgical and anatomic neck fractures
• greater tuberosity fracture displaced < 5mm
• >5mm displacement will result in impingement with loss of abduction and external rotation
• fractures in patients who are not surgical candidates
• additional variables to consider
• age
• fracture type
• fracture displacement
• bone quality
• dominance
• general medical condition
• concurrent injuries
• outcomes
• immediate physical therapy results in faster recover
• Operative
• CRPP (closed reduction percutaneous pinning)
• indications
• 2-part surgical neck fractures
• 3-part and valgus-impacted 4-part fractures in patients with good bone quality, minimal metaphyseal comminution, and intact medial calcar
• outcomes
• considerably higher complication rate compared to ORIF, HA, and RSA
• axillary nerve at risk with lateral pins
• musculocutaneous nerve, cephalic vein, and bicep tendon at risk with anterior pins

• ORIF

• indications
• greater tuberosity displaced > 5mm
• 2-, 3-, and 4-part fractures in younger patients
• head-splitting fractures in younger patients
• outcomes
• medial support necessary for fractures with posteromedial comminution
• consider use of a fibula strut if concerned about medial support
• calcar screw placement critical to decrease varus collapse of head

• Intramedullary nailing

• indications
• surgical neck fractures or 3-part greater tuberosity fractures in younger patients
• combined proximal humerus and humeral shaft fractures
• outcomes
• biomechanically inferior with torsional stress compared to plates
• favorable rates of fracture healing and ROM compared to ORIF

• Arthroplasty

• indications
  • hemiarthroplasty
    • younger patients (40-65 years old) with complex fractures or head-splitting components likely to have complications with ORIF
    • recommended use of convertible stems to permit easier conversion to RSA if necessary in future
  • reverse total shoulder
    • low-demand elderly individuals with non-reconstructible tuberosities and poor bone stock
    • low-demand patients with fracture dislocation
• outcomes
• improved results if
• anatomic tuberosity reduction and healing
• restoration of humeral height and version
  • humeral height is best judged from the superior border of the pectoralis major insertion
• poor results with
  • tuberosity nonunion or malunion
  • retroversion of humeral component > 40°

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