Updated: 11/7/2018

Triquetrum Fracture

Review Topic
  • Epidemiology
    • incidence
      • second most common carpal bone fracture
      • accounts for up to 15% of all carpal fractures
  • Pathophysiology
    • mechanism of injury
      • based on type of fracture
        • dorsal cortical fractures
          • impaction
            • most common mechanism
            • usually a fall onto wrist in dorsiflexion and ulnar deviation
            • ulnar styloid can act as a chisel driven into the dorsal cortex of the triquetrum
          • avulsion
            • results from extreme palmar flexion with radial deviation
              • due to attachment of dorsal radiotriquetral and triquetroscaphoid ligaments
          • shearing force
            • results from shearing of proximal edge of the hamate against the distal dorsal triquetrum during wrist extension
        • body fractures
          • sagittal fractures
            • results from axial dislocations or anterior-posterior crush injury
          • medial tuberosity fractures
            • results from direct blow
          • transverse proximal pole fractures
            • associated with perilunate dislocations
          • transverse body fractures
            • associated with perilunate dislocations
          • comminuted fractures
            • results from high-energy trauma
        • palmar cortical fractures
          • avulsion of palmar ulnar triquetral ligament and LTIO ligament
          • shearing force from pisiform
  • Associated conditions
    • perilunate dislocations (seen in 12-25% of triquetral fractures)
    • radius or ulna fractures
  • Osteology
    • triquetrum is a wedge-shaped carpal bone located in the proximal row
    • articulates with
      • hamate
      • pisiform
      • lunate
  • Ligaments
    • extrinsic
      • ulnotriquetral ligament
        • originates from the palmar aspect of the triangular fibrocartilage complex (TFCC)
        • inserts on the palmar aspect of the triquetrum
      • dorsal radiotriquetral (radiocarpal) ligament
        • originates from the dorsal distal radius
        • inserts on the dorsal ridge of the triquetrum
    • intrinsic
      • palmar and dorsal lunotriquetral ligaments
        • palmar ligament is thicker and stronger
        • distal fibers blend with scapholunate ligament to form palmar and dorsal scaphotriquetral ligaments
      • triquetrocapitate and triquetrohamate ligaments
        • blend with ulnocapitate ligament to form ulnar arm of arcuate ligament
      • dorsal intercarpal ligament
        • originates from ulnar aspect of dorsal triquetrum
        • inserts on dorsal rim of the scaphoid, trapezium, and trapezoid
  • Blood Supply
    • receives blood supply from nutrient arteries to non-articular surfaces
Triquetrum Fractures
Dorsal cortical fractures
 • most common (accounts for up to 93%)
 • mechanism includes avulsion, shearing force, or impaction

Body fractures
 • second most common
 • subtypes: sagittal, medial tuberosity, transverse proximal pole, transverse body, comminuted

Palmar cortical fractures
 • mechanism includes avulsion or shearing force
 • risk of instability

  • Physical exam
    • swelling/deformity of ulnar wrist
    • pain with palpation directly over triquetrum
    • pain with wrist flexion and extension if dorsal cortical fracture
  • Radiographs
    • recommended views
      • PA
      • lateral
        • useful for visualizing dorsal cortical fractures
      • IR oblique
        • useful for visualizing dorsal cortical fractures
    • optional views
      • radial deviation
        • may be helpful in identifying palmar cortical fractures
  • findings
    • "pooping duck" sign
      • represents dorsal cortical fractures
  • CT
    • indications
      • obtain if high suspicion of triquetral fracture
  • MRI
    • indications
      • recommended for palmar cortical fractures due to concern for carpal instability
      • obtain if concern for extrinsic intercarpal ligament injuries or occult fracture
  • Nonoperative
    • immobilization for 4-6 weeks
      • indications
        • dorsal cortical fractures without evidence of instability
        • nondisplaced body fractures
        • palmar cortical fractures without evidence of instability
  • Operative
    • ORIF
      • indications
        • dorsal cortical fractures with evidence of instability
        • displaced body fractures
        • palmar cortical fractures with evidence of instability
  • Open reduction internal fixation
    • approach
      • dorso-ulnar approach
        • radial to ECU
    • soft tissue
      • longitudinal capsulotomy
    • instrumentation
      • interfragmentary screws
      • suture anchors
        • if ligamentous injury requiring repair
      • K wires
        • if instability
  • Non-union
    • rare in triquetral body fractures
    • can perform excision if symptomatic
  • Persistent carpal instability
  • Pisotriquetral arthritis

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