SynopsisCodesLook ForDiagnostic PearlsDifferential Diagnosis & PitfallsBest TestsManagement PearlsTherapyReferences
Ulnar shaft fracture
Other Resources UpToDate PubMed

Ulnar shaft fracture

Contributors: William Zhuang, Danielle Wilbur MD
Other Resources UpToDate PubMed


Emergent Care / Stabilization:
  • Reduction
  • Immobilization
Causes / typical injury mechanism: Ulnar shaft fractures typically result from direct trauma to the medial forearm, such as with blocking a blow from a bat or a nightstick. These are commonly called "nightstick fractures." This fracture can also be seen after a fall.

Classic history and presentation: Patients present with localized tenderness and swelling of the forearm following a blow to the medial forearm or a fall.

Prevalence: Bimodal distribution.
  • Younger, active men
  • Older women
Risk factors:
  • Athletic participation or an active lifestyle
  • Increased age in women, due to osteopenia / osteoporosis
  • Living in an area with a higher prevalence of violence
Pathophysiology: A direct blow to the ulna or axial load across the ulna leads to this type of fracture.

Grade / classification system: 
  • Stable –
    • Displacement of less than 50%
    • Angulation of less than 15 degrees
    • Location in middle and distal third of ulna
  • Unstable –
    • Displacement of more than 50%
    • Angulation of more than 15 degrees
    • Ipsilateral instability of distal radial ulnar joint or proximal radial ulnar joint
AO / Orthopaedic Trauma Association (OTA) Classification
Ulna fractures are classified as 2U fractures, and then further classified as:
  • 2U2: Diaphyseal segment of ulna fracture
Ulna fractures are further classified by type:
  • Type A: Simple fractures
    • A1: Spiral
    • A2: Oblique (greater than or equal to 30 degrees)
    • A3: Transverse (less than 30 degrees)
  • Type B: Wedge fracture
    • B2: Intact wedge
    • B3: Fragmentary wedge
  • Type C: Multifragmentary
    • C2: Intact segmental
    • C3: Fragmentary segmental
Ulnar shaft fractures should also be classified as open or closed.


S52.209A – Unspecified fracture of shaft of unspecified ulna, initial encounter for closed fracture
S52.209B – Unspecified fracture of shaft of unspecified ulna, initial encounter for open fracture type I or II
S52.209C – Unspecified fracture of shaft of unspecified ulna, initial encounter for open fracture type IIIA, IIIB, or IIIC

42760000 – Open fracture of shaft of ulna
53792000 – Closed fracture of shaft of ulna

Look For

Subscription Required

Diagnostic Pearls

Subscription Required

Differential Diagnosis & Pitfalls

To perform a comparison, select diagnoses from the classic differential

Subscription Required

Best Tests

Subscription Required

Management Pearls

Subscription Required


Subscription Required


Subscription Required

Last Reviewed:01/14/2024
Last Updated:01/18/2024
Copyright © 2024 VisualDx®. All rights reserved.
Ulnar shaft fracture
Copyright © 2024 VisualDx®. All rights reserved.