Monteggia Fractures - Trauma

Introduction

Injury defined as
- proximal 1/3 ulnar fracture with associated radial head dislocation/instability
Epidemiology
- rare in adults
- more common in children with peak incidence between 4 and 10 years of age
  - different treatment protocol for children
Associated injuries
- may be part of complex injury pattern including
  - olecranon fracture-dislocation
  - radial head fx
  - coronoid fx
  - LCL injury
  - terrible triad of elbow
Prognosis
- if diagnosis is delayed greater than 2-3 weeks complication rates increase significantly

Anatomy

Classification

Bado Classification
Type I	60%	Fracture of the proximal or middle third of the ulna with anterior dislocation of the radial head (most common in children and young adults)
Type II	15%	Fracture of the proximal or middle third of the ulna with posterior dislocation of the radial head (70 to 80% of adult Monteggia fractures)
Type III	20%	Fracture of the ulnar metaphysis (distal to coronoid process) with lateral dislocation of the radial head
Type IV	5%	Fracture of the proximal or middle third of the ulna and radius with dislocation of the radial head in any direction

Jupiter Classification of Type II Monteggia Fracture-Dislocations
Type IIA	Coronoid level
Type IIB	Metaphyseal-diaphyseal junction
Type IIC	Distal to coronoid
Type IID	Fracture extending to distal half of ulna

Presentation

Imaging

Treatment

Techniques

ORIF of ulnar shaft fracture
- approach
  - lateral decubitus position with arm over padded support
  - midline posterior incision placed lateral to tip of olecranon
  - develop interval between flexor carpi ulnaris and anconeus along ulnar border proximally, and interval between FCU and ECU distally
- techniques
  - with proper alignment of ulna radial head usually reduces and open reduction of radial head is rarely needed
  - failure to align ulna will lead to chronic dislocation of radial head
ORIF of radial head
- approach
  - posterolateral (Kocher) approach
- technique
  - annular ligament often found interposed in radiohumeral joint preventing anatomic reduction after ulnar ORIF
    - treatment based on involved components (radial head, coronoid, LCL)

Complications

PIN neuropathy
- up to 10% in acute injuries
- treatment
  - observation for 2-3 months
    - spontaneously resolves in most cases
    - if no improvement obtain nerve conduction studies
Malunion with radial head dislocation
- usually caused by failure to obtain anatomic alignment of ulna
- treatment
  - ulnar osteotomy and open reduction of the radial head