Monteggia's Fracture

Aka: Monteggia's Fracture, Monteggia's Dislocation, Monteggia Fracture, Monteggia Fracture Dislocation

1. See Also
   1. Forearm Fracture (GRUM Mnemonic)
   2. Galeazzi Fracture
   3. Radial Head Dislocation
2. Definitions
   1. Monteggia Fracture
      1. Proximal Ulna Fracture AND Radial Head Dislocation
3. Mechanism
   1. Fall on Outstretched Hand WITH
   2. Extended elbow AND Hyperpronated Forearm
4. Signs
   1. Decreased elbow range of motion
   2. Proximal third ulna tenderness, swelling, deformity suggesting Fracture of shaft (typically displaced)
   3. Proximal Radial Head Dislocation
      1. Perform a careful Hand Neurovascular Exam
      2. Risk of Radial Nerve injury (including posterior interosseous nerve which branches from Radial Nerve)
      3. Evaluate extension of thumb, wrist and MCP joint
5. Types: Bado Classification
   1. Type 1: Extension (60-70% of Fractures, esp. children)
      1. Radial head dislocates anteriorly
   2. Type 2: Flexion (15% of Fractures, esp. adults)
      1. Radial head dislocates posteriorly or posterior-laterally
   3. Type 3: Lateral (20% of Fractures)
      1. Radial head dislocates laterally or anterior-laterally
   4. Type 4: Combined (1% of Fractures)
      1. Radial head dislocates anteriorly AND
      2. Radial Fracture (in addition to the proximal Ulna Fracture)
6. Differential Diagnosis
   1. See Forearm Fracture (GRUM Mnemonic)
   2. See Radial Head Dislocation
   3. Galeazzi Fracture
   4. Elbow Dislocation
7. Imaging: Forearm XRay
   1. Images
      1. 
   2. Ulna Fracture may not be obvious (greenstick Fracture)
   3. Radial Head Dislocation may be subtle and overlooked
      1. Draw a radiocapitellar line using lateral Elbow XRay (with elbow at 90 degrees)
      2. Radiocapitellar line drawn down the longitudinal midline of the radius should pass through the capitellum
   4. Xray joint above and below Forearm (standard protocol)
      1. Wrist XRay
      2. Elbow XRay
8. Management
   1. Acute Management
      1. Most adult cases will require operative management with ORIF
      2. Emergent orthopedic consult for displaced Monteggia Fracture Dislocations (unstable)
      3. Closed reduction AND Long Arm Splint immobilization for stable, non-displaced Fractures
         1. Reduce BOTH the Ulna Fracture and the Radial Head Dislocation
   2. Follow-up with orthopedic surgery
      1. Child: Closed reduction may suffice
      2. Adult: Open reduction and internal fixation (ORIF)
9. Complications
   1. Missed Radial Head Dislocation
      1. Chronic unreducible dislocated radial head
      2. Results in Chronic Pain and limited Forearm supination and pronation
   2. Posterior interosseous nerve palsy
      1. Results from Radial Head Dislocation
      2. Results in loss of thumb extension and loss of metacarpophalangeal joint (MCP) extension
      3. Preserved wrist extension
10. References
    1. Beutel (2012) Orthopedics 35:138-44
       1. http://m3.wyanokecdn.com/b66c8c9139965793f132ca2210e3033b.pdf
    2. Delpont (2018) Orthop Traumatol Surg Res 104(1):S113-20
    3. Hartman, Morrissey and Kiel (2020) Crit Dec Emerg Med 34(1): 16-17
    4. Johnson and Silberman (2021) Monteggia Fractures, StatPearls, Treasure Island, FL
       1. https://www.ncbi.nlm.nih.gov/books/NBK470575/