Proximal Humerus Fracture Malunion and Nonunion

Question 1

Proximal Humerus Fracture Malunion and Nonunion can lead to

Answer 1

Malunion can lead to malposition of the humeral tuberosities; rotation, angulation, and/or offset of the head-shaft

Question 2

Epidemiology

Answer 2

• incidence
  
  • proximal humerus fractures account for 4% to 5% of all fractures
• risk factors for nonunion
  
  • fracture characteristics
    
    • 3 or 4 part fracture patterns
    • humeral head split
    • displaced tuberosity fractures
  • patient factors
    
    • osteoporosis
    • chronic renal disease
    • chronic alcohol or steriod use
    • smoking

Question 3

Pathophysiology of malunion and or the site of malunion at the proximal humerus

Answer 3

• origin of malunion
  
  • initial fracture displacement
  • secondary displacement after loss of reduction
  • failure of internal fixation
• humeral head malunion
  
  • varus/valgus
  • impacted (>1cm displacement)
  • articular surface incongruity (e.g. head split)
• greater tuberosity malunion
  
  • usually displaced posterior, superior and externally rotated
• lesser tuberosity malunion
  
  • usually displaced medial

Question 4

Associated conditions

Answer 4

• rotator cuff tearing
• osteonecrosis of humeral head
• glenohumeral joint issues
  
  • stiffness
  • post-traumatic arthritis
  • subluxation or dislocation
  • subacromial impingement

Question 5

Humeral head

Answer 5

• shape
  
  • spheroidal in 90% of individuals
• size
  
  • average diameter is 43 mm
• orientation
  
  • retroverted 30° from transepicondylar axis of the distal humerus
  • neck-shaft agle usually 130° to 140°

Question 6

Greater tuberosity

Answer 6

position important for rotator cuff muscle fuction

• horizontal position
  
  • medial edge of tuberosity is 10mm lateral to humeral canal axis
• vertical position
  
  • superior edge of tuberosity is 6mm inferior to upper edge of humeral head

Question 7

Classification

Answer 7

1. Beredjiklian et al.
2. Boileau et al.

Question 8

Classification

Beredjiklian et al.

Answer 8

Question 9

Classification

Boileau

Answer 9

Question 10

Presentation

Answer 10

motion

• active and passive shoulder range-of-motion
  
  • blocks or crepitus should be noted
• rotator cuff
  
  • greater tuberosity malunion = weakness with abduction, external rotation
  • lesser tuberosity malunion = weakness with internal rotation
• instability
  
  • humeral head malunion = apprehension test

Question 11

Imaging Radiographs

Answer 11

Radiographs

• recommended views
  
  • true AP, scapular Y, axillary
• optional views
  
  • apical oblique
  • Velpeau
  • West Point axillary
• findings
  
  • neck-shaft angle = varus or valgus
  • greater tuberosity = superiorly and posteriorly displaced, externally rotated
  • lesser tuberosity = medialized
• measurements
  
  • humeral head
    
    • > 45° of deformity in any plane
    • symptomatic articular incongruity
    • neck-shaft angle <120° or >150°
  • greater or lesser tuberosity
    
    • >1 cm from native anatomical position

Question 12

CT scan

Answer 12

• indications
  
  • preoperative planning
  • assess bone stock, orientation and articular surface
• findings< >humeral head and greater tuberosity displacementglenoid version and glenoid bone stockarticular injury

Question 13

MRI

Answer 13

• indications
  
  • preoperative planning
  • soft-tissue structures
• findings
  
  • rotator cuff or labral injury
  • deltoid atrophy secondary to axillary nerve injury
  • long-head biceps injury
  • osteonecrosis

Question 14

Studies

Answer 14

you must role out infection in any revesion or nonunion

• Labs
  
  • CBC, ESR, CRP, blood cultures to rule out infection
• Electrodiagnositcs
  
  • concern for nerve dysfunction

Question 15

Nonoperative

Answer 15

NSAIDS, physical therapy, occasional corticosteriod injection

• indications
  
  • low-demand patient
  • painless shoulder limitations
  • unable to comply with rehabilitation protocol
• modalities
  
  • physical therapy
    
    • maximize ROM and strengthening program
• outcomes
  
  • impacted varus and valgus fractures show good-to-excellent results
    
    • return to 90% of normal fuction

Question 16

Operative

Answer 16

1. ORIF +/- osteotomy, subacromial decompression, and soft tissue technique
2. shoulder arthroplasty

Question 17

ORIF +/- osteotomy, subacromial decompression, and soft tissue technique

Answer 17

• indications
  
  • symptomatic malunion following
    
    • nonoperative treatment
    • failed internal fixation
  • anatomical requirements
    
    • adequate bone stock for fixation
    • preserved articular surface
    • intact blood supply to humeral head
• techniques
  
  • humeral head deformities
    
    • minor deformity techniques
      
      • open/arthroscopic tuberoplasty
      • +/- acromioplasty
      • +/- capsular release
      • +/- bursectomy
    • severe deformity techniques
      
      • varus/valgus osteotomy
      • +/- rotational osteotomy and lateral plate fixation
        
        • treated with corrective osteotomy/fixation if patient is young or active
        • may be augmented with strut allograft for poor bone stock
  • greater tuberosity deformities
    
    • <1.5 cm displacement
      
      • arthroscopic subacromial decompression +/- rotator cuff repair
    • >1.5 cm displacement
      
      • open/arthroscopic tuberosity osteotomy +/- subacromial decompression
• outcomes

complication rates associated with surgical management of malunions are higher than those associated with acute fractures

Question 18

shoulder arthroplasty

Answer 18

• indications
  
  • symptomatic malunion following
    
    • nonoperative treatment
    • failed internal fixation
  • anatomical requirements
    
    • inadequate bone stock for fixation techniques
    • articular incongruity, destruction or collapse (e.g. osteonecrosis or head-split)
    • compromised blood supply
    • chronic dislocation
• techniques
  
  • hemiarthroplasty
  • total shoulder arthroplasty
  • reverse total shoulder arthroplasty

Question 19

Complications

Answer 19

• Persistent pain and weakness
• Stiffness
• Loss of fixation
• Infection
• Bleeding