Humeral Shaft Nonunion

Question 1

what is Humeral Shaft Nonunion

Answer 1

Characterized by the arrest of the fracture repair process of a humeral shaft fracture

• treated operatively with compression plating with or without bone grafting

Question 2

incidence of primary nonunion

Answer 2

incidence of primary nonunion

• 2 to 33% with nonoperative management
• 5 to 10% with surgical management

Question 3

location

Answer 3

location

• proximal third humeral shaft fractures are felt to have higher rates of nonunion

Question 4

risk factors

Answer 4

• biologic
  
  • metabolic/endocrine abnormalities (osteoporosis, Vitamin D deficiency most common)
  • infection
  • patient factors (smoking, obesity, malnutrition, noncompliance)
  • open fracture
• mechanical
  
  • unstable fracture patterns with inadequate stability
  • shoulder or elbow stiffness (motion directed to fracture site)

Question 5

Prognosis

Answer 5

with operative treatment of nonunion, 83%-100% of patients go on to union

Question 6

Pathophysiology

Answer 6

• inadequate stability at fracture site with operative or nonoperative treatment
• inadequate biology as a result of metabolic/endocrine abnormalities, infection, smaller bone surface area for healing

Question 7

Anatomy

Answer 7

• Blood Supply
  
  • nutrient vessel of humerus courses along the medial aspect of the mid to distal third of the diaphysis
• Muscles
  
  • pectoralis major and deltoid create strong deforming forces on proximal diaphyseal fractures
• Tendon
  
  • biceps tendon interposition in proximal diaphyseal fractures may lead nonunion

Question 8

Presentation

Answer 8

• Symptoms
  
  • pain with use of the extremity
• Physical exam
  
  • inspection
    
    • assess the fit of functional brace and skin irritation
    • atrophy
    • angulation
  • motion
    
    • gross motion at the fracture site
  • neurovascular
    
    • assess radial nerve function

Question 9

Imaging

Answer 9

• Radiographs
  
  • recommended views
    
    • AP and lateral of the humerus, shoulder, and elbow
  • findings
    
    • lack of fracture consolidation
    • hypertrophic callous formation
    • pseudarthrosis
• CT
  
  • indications
    
    • to evaluate for the extent of bridging callous and preoperative planning

Question 10

Studies

Answer 10

• CRP, ESR, CBC
  
  • must rule out infection
• total protein and serum albumin
• vitamin D, TSH, PTH

Question 11

Nonoperative

Answer 11

unctional bracing +/- bone stimulation

• indications
  
  • rarely indicated

Question 12

Operative

Answer 12

1. compression plating with bone grafting (gold standard)
2. dual plating
3. cortical strut allograft/autograft
4. bone morphogenic proteins (BMP’s)

Question 13

compression plating with bone grafting (gold standard

Answer 13

• indications
  
  • symptomatic nonunion
• outcomes
  
  • shown to be superior IM nailing

Question 14

dual plating

Answer 14

• indications
  
  • very proximal or distal fracture nonunion
  • poor metaphyseal bone quality
  • micromotion noted at fracture site following single plate fixation
• outcomes
  
  • 92-100% union at 16 weeks

Question 15

cortical strut allograft/autograft

Answer 15

• free fibular grafting
• indications
  
  • recalcitrant atrophic nonunions
• indications
  
  • severe osteopenia from disuse, age, or prior surgery
  • severe bone loss
  • recalcitrant nonunion
• outcomes
  
  • 95-100% union rate

Question 16

bone morphogenic proteins (BMP’s)

Answer 16

indications

• limited role as no studies show improved outcomes