Fractures of the Humeral Shaft

Classification

By location, fracture pattern, comminution, soft tissue injury, mechanism

AO

• Type A : simple
  • A single circumferential disruption of the diaphysis 
  • May be :
    1. Spiral
    2. Oblique (angle >30 degrees)
    3. Transverse (angle less than 30 degrees)
• Type B multifragmentary : wedge
  • A fracture with one or more intermediate fragments in which after reduction, there is some contact between the main fragments
  • May be :
    1. Spiral wedge
    2. Bending wedge
    3. Fragmented wedge
• Type C multifragmentary : complex
  • A fracture with one or more intermediate fragments in which after reduction, there is no contact between the main proximal and distal fragments
  • May be :
    1. Spiral
    2. Segmental
    3. Irregular

Anatomy

• Fracture above the level of pectoralis major allows the proximal fragment to abduct and rotate externally due to the action of the rotator cuff
• Fracture above the deltoid and below pectoralis major : deltoid pulls the distal fragment laterally, pectoralis major pulls the proximal fragment medially
• Fracture below deltoid : proximal fragment abducts due to deltoid, distal fragment pulled medially and proximally by biceps/brachialis and coracobrachialis
• Holstein- Lewis fracture : distal 1/3 shaft fracture. May cause palsy seconary to tethering of radial nerve in lateral intermuscular septum  or entrapment in fracture site
• Radial nerve anatomy:
  • pierces lateral intermuscular septum at juntcion of middle and distal thirds of the distance from the acromion to the lateral epicondyle

Treatment

Reduction Tolerances

• Shortening less than 2-3 cm
• 20 degrees of anteroposterior angulation
• 30 degrees of varus/valgus angulation

Operative Indications

• Vascular injury
• Bilateral humerus fractures
• Associated lower extremity fracture (to allow for crutch use)
• Segmental fractures
• Floating elbow
• Open fracture
• Failure to obtain or maintain reduction with closed means
• Fracture in associated with displaced intra-articular fracture
• Pathological fracture

Nonoperative Management

• Initial stabilization with U-shaped coaptation splint for the first 7-10 days
• Definitive management:
  • Functional bracing (Sarmiento)
    • requires daily adjusting as swelling subsides
    • Average duration: 12 weeks
    • nonunion: 10-20%
      • Higher nonunion rates for proximal 1/3 oblique fractures, simple fracture patterns
      • Segmental fractures may be difficult to brace

Operative options

• Plate
  • Patients can be weight bearing as tolerated if the fracture is fixed with a 4.5 mm DCP plate and eight cortices of fixation on both sides of the fracture
    
    
    • Preferrably 5 screw holes on each side of fracture and at least three bicortical screws
  • 90-95% union rate
  • Disadvantages:
    • scar, potential, iatrogenic nerve injury, infection, nonunion
  • Surgical approaches:
    • Posterior
      • Interval between lateral and long head of triceps
      • Cannot be extended proximally therefore better for distal fractures
    • Anterior
      • brachialis splitting approach (lateral 1/3 innervated by radial nerve)
    • Anterolateral
      • Interval between brachialis and brachioradialis
      • Extensile approach both proximally and distally
    • Lateral
      • distal 1/3 fractures
• Intramedullary Nail (Retrograde or antegrade)
  • Union rates good but inferior to plating
  • Consider for:
    • Pathologic fractures
    • Osteoporosis
    • Comminuted fractures
  • Options:
    • Antegrade
    • Retrograde
  • Complications:
    • Nonunion
    • Nerve injury with reaming
      • maintian accurate reduction
      • avoid reaming across the fracture site
    • Antegrade nail complications:
      • Shoulder stiffness
      • Rotator cuff injury
      • Shoulder pain 15% 
    • Retrograde nail complications
      • elbow pain
      • supracondylr fracture
    • Nerve injury secondary to placement of distal interlocking screws
      • Lateral to medial screws injure the radial nerve
      • Anterior to posterior screws injure the musculoskeletal nerve
• External fixation
  • Typically employed for fractures with severe soft tissue injury, infection, and burns

Complications

Radial Nerve Palsy

• The palsy is usually the result of a neuropraxia
• Incidence of radial nerve palsy after a humeral shaft fracture is 8 – 15%:
  • 5% proximal 1/3
  • 14.6% middle 1/3
  • 19.4% distal 1/3
  • 2.5% after ORIF
  • 2% after manipulation
• Full spontaneous recovery expected in 70% of patients at  3 months and in 95% of patients at 4 months.
• Management of closed fracture with dense radial nerve palsy is observation.
• Laceration or entrapment is most commonly associated with spiral fractures of the distal 1/3 of the humerus (Holstein-Lewis fracture) and gun shot wounds
• Treatment of radial nerve palsy:
  • Observation:
    • Closed fractures with complete nerve palsy can be observed
    • Consider ultrasound within 3 weeks
      • if nerve is entrapped or transected proceed with surgical management
    • f no improvement is seen at six weeks, obtain an EMG/NCV study.
      • If fasciculations are seen, continue observation as this is evidence of reinnervation.
      • Fibrillations are evidence of denervation and exploration is indicated.
  • Indications for exploration:
    • Open fractures
    • Presence of associated vascular injury.
    • Penetrating trauma.
    • Management of a palsy that begins after closed reduction is controversial.
    • Exploration of Holstein-Lewis fractures associated with a radial nerve palsy is also controversial.  If a closed anatomic reduction can be attained, one may observe.

Nonunion

• Defined as no sign of union by 4 months
• Higher risk in transverse fracture, open fracture, high energy trauma
• Treat with plating and bone graft
• Expect 95% to unite