Updated: 2/1/2021

Isolated Ulnar Shaft Fracture

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  • Isolated ulnar shaft fractures are rare fractures of the forearm caused by either direct blow to the forearm ("nightstick" fracture) or indirect trauma (fall).
  • Diagnosis and treatment plans made primarily by physical exam and plain radiographs.
  • Minimally displaced (< 50% displacement and < 10° of angulation) are often treated nonsurgically, while treatment has historically been surgical open reduction and internal fixation with compression plating for displaced fractures.
  • Epidemiology
    • incidence
      • rare (< 1% of upper extremity fractures)
    • demographics
      • highest incidence in
        • men between age 10 and 20 
        • women over age of 60
  • Pathophysiology
    • mechanism of injury
      • direct trauma
        • direct blow to forearm ("nightstick" fracture)
      • indirect trauma
        • motor vehicle accidents
        • falls from height
          • axial load applied to the forearm through the hand 
  • Associated conditions
    • elbow and DRUJ injuries
      • Monteggia fractures 
      • Essex-Lopresti injuries
    • compartment syndrome 
      • evaluate compartment pressures if concern for compartment syndrome
  • Prognosis
    • For minimally displaced and angulated fractures (< 50% displacement and < 10° of angulation), nonoperative management has equivalent clinical outcomes to surgical treatment.
  • Osteology
    • axis of rotation of forearm runs through radial head (proximal) and ulna fovea (distal)
      • distal radius effectively rotates around the distal ulna in prono-supination
      • the ulna and radius from a functional unit; mal-angulation of ulna fractures can lead to limitation of forearm rotation
  • Ligaments
    • Interosseous membrane (IOM) 
      • occupies the space between the radius and ulna
        • permits rotation of the radius around the ulna
      • comprised of 5 ligaments 
        • central band is key portion of IOM to be reconstructed
        • accessory band
        • distal oblique bundle
        • proximal oblique cord
        • dorsal oblique accessory cord
  • Descriptive
    • closed versus open
    • location
    • comminuted, segmental, multi-fragmented
    • displacement
    • angulation
    • rotational alignment
  • OTA classification
    • ulna diaphyseal fractures 
      • Type A (simple) 
        • simple fracture that is spiral (A1), oblique (A2), or transverse (A3)
      • Type B (wedge) 
        • wedge fracture that is intact (B2) or fragmentary (B3)
      • Type C (multifragmentary) 
        • multifragmentary fracture that is intact segmental (C2) or fragmentary segmental (C3)
  • Symptoms
    • pain and swelling
    • loss of forearm and hand function
  • Physical exam  
    • inspection
      • gross deformity
      • open injuries
      • check for tense forearm compartments
    • neurovascular exam
      • assess radial and ulnar pulses
      • document median, radial, and ulnar nerve function
    • provocative tests
      • pain with passive stretch of fingers
        • alert to impending or present compartment syndrome
  • Radiographs
    • recommended views
      • AP and lateral views of the forearm 
    • additional views
      • oblique forearm views for further fracture definition
      • ipsilateral AP and lateral of the wrist and elbow
        • to evaluate for associated fractures or dislocation
        • radial head must be aligned with the capitulum on all views
  • Nonoperative 
    • cast or brace immobilization, soft compression dressing  
      • indications
        • isolated nondisplaced or distal 2/3 ulna shaft fx (nightstick fx) with
          • < 50% displacement and
          • < 10° of angulation 
      • modality
        • bracing
          • functional fracture brace
        • casting
          • Muenster cast with good interosseous mold 
        • soft compression dressings
          • allowing immediate mobilization
      • outcomes
        • union rates > 92% if above criteria met
        • similar union and functional outcomes with casting and bracing/soft compression dressings
  • Operative
    • external fixation
      • indications
        • severe soft tissue injury (Gustilo IIIB)
    • ORIF
      • indications 
        • displaced distal 2/3 isolated ulna fractures
        • proximal 1/3 isolated ulna fractures
        • Gustilo I, II, and IIIa open fractures may be treated with primary ORIF 
      • outcomes
        • goal is for cortical opposition, compression, and restoration of forearm anatomy
    • ORIF with bone grafting
      • indications
        • open fractures with significant bone loss (bone grafting often performed in a delayed fashion) 
        • nonunions 
      • outcomes
        • use of autograft is critical to achieve fracture union
      • technique
        • cancellous autograft
          • indications
            • ulnar fractures with significant bone loss
        • vascularized fibula grafts
          • indications
            • can be used for large defects and have a lower rate of infection 
        • Masquelet technique
          • indications
            • utilized in cases of non-union or open fractures with significant bone loss
    • IM nailing
      • indications
        • poor soft-tissue integrity
      • outcomes
        • recent studies have shown similar union rates compared to ORIF for isolated ulnar shaft fractures
  • Cast or brace immobilization, soft compression dressing
    • technique
      • cast/brace may extend just above elbow to control forearm rotation, however, randomized studies have shown no difference in outcomes between above elbow and below elbow immobilization
        • monitor very closely (~1 week) for displacement
        • should be worn for at least 6 weeks
        • Some authors have advocated for immediate mobilization as tolerated
  • External fixation 
    • technique
      • 2nd and 3rd metacarpal shaft can both be utilized for distal pin placement
      • pin diameter should not exceed 4 mm
  • ORIF 
    • approach
      • subcutaneous approach to ulna shaft 
    • technique
      • 3.5 mm DCP plate (AO technique) is standard 
        • 4.5 plates no longer used due to increased rate of re-fracture following removal
      • compression mode preferred when the fracture allows to achieve anatomic primary bony healing
        • to minimize strain, six cortices proximal and distal to fracture should be engaged
      • locked plates are increasingly indicated over conventional plates in osteoporotic bone 
      • bridge plating may be used in extensively comminuted fractures 
      • interfragmentary lag screws (2.0 or 2.7 screws) if necessary 
      • open fractures 
        • irrigation and debridement should be performed to remove any contaminated tissue or bony fragments without soft tissue attachments
    • postoperative care
      • early ROM unless there is an injury to proximal or distal joint
      • should be managed with a period of non-weight bearing due to risk of secondary displacement of the fracture 
        • generally 6 weeks
  • ORIF with bone grafting
    • technique 
      • bone graft options
        • cancellous autograft
          • iliac crest, proxmial tibia, reamer-irrigator-aspirator (RIA)
        • vascularized fibula grafts 
        • Masquelet technique ("induced-membrane" technique) can also be utilized in cases of non-union or open fractures with significant bone loss
          • 2 stage technique
            • 1st stage: I&D, cement spacer and temporizing fixation 
            • 2nd stage: placement of bone graft into "induced membrane" and definitive fixation 
              • Studies show optimal time frame for bone grafting to be 4-6 weeks after placement of cement spacer
  • IM nailing
    • approach
      • inserted through the posterior olecranon
    • technique
      • may use a small incision at fracture site to facilitate passing of nail

  • Infection
    • incidence
      • 3% incidence with ORIF
    • risk factors
      • open fractures
  • Compartment syndrome
    • incidence
      • up to 15% depending on mechanism and fracture characteristics
    • risk factors
      • high energy crush injury
      • open fractures
      • low velocity GSWs
      • vascular injuries
      • coagulopathies (DIC)
  • Nonunion
    • incidence
      • < 5% after compression plating 
      • up to 12% in extensively comminuted fractures treated with bridge plating
    • risk factors
      • extensive comminution
      • poorly applied plate fixation
    • treatment
      • atrophic nonunions can be treated with 3.5 mm plates and autogenous cancellous bone grafting 
      • Infection and atrophic nonunions can also be treated with the Masquelet technique
      • Hypertrophic nonunions treated with debridement and compression plating
  • Malunion  
    • risk factors
      • direct correlation between restoration of radial bow and functional outcome
  • Neurovascular injury
    • risk factors
      • PIN injury with Monteggia fxs
      • Type III open fxs
    • treatment
      • observe for three months to see if nerve function returns
        • explore if no return of function after 3 months
  • Refracture 
    • incidence
      • up to 10% with early hardware removal
    • risk factors
      • removing plate too early 
        • plates should not be removed < 1 year from implantation
      • large plates (4.5 mm)
      • comminuted fractures
      • persistent radiographic lucency
    • treatment
      • wear functional forearm brace for 6 weeks and protect activity for 3 months after plate removal

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(OBQ10.85) A 25-year-old female sustains the isolated fracture seen in Figure A. The patient elects to have nonoperative management. When compared to operative treatment, which of the following is true of the clinical outcome following nonoperative management?

QID: 3173

Long arm cast immobilization is necessary with nonoperative management




Twenty degree loss of forearm rotation is expected with nonoperative management




Loss of wrist motion is expected with nonoperative management




Loss of elbow motion is expected with nonoperative management




Equivalent clinical outcomes



L 2 C

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(OBQ05.178) A 42-year-old male sustains a closed, isolated ulna shaft fracture with 2mm displacement and 3 degrees valgus angulation. He is treated conservatively with early range of motion but presents at one year with a painful atrophic nonunion. What treatment is indicated at this time?

QID: 1064

Dynamic splinting




Open autogenous cancellous bone grafting




Open reduction internal fixation with autogenous bone grafting




Closed reduction and percutaneous pinning




Use of an implantable ultrasound device



L 1 C

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Evidence (10)
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