183ms
Updated: Jul 14 2021

Scaphoid Fracture

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Average 4.3 of 99 Ratings

Images
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  • Summary
    • Scaphoid Fractures are the most common carpal bone fracture, often occurring after a fall onto an outstretched hand.
    • Diagnosis can generally be made by dedicated radiographs but CT or MRI may be needed for confirmation.
    • Treatment may require a prolonged period of cast immobilization, percutaneous surgical fixation, or open reduction and internal fixation. 
  • Epidemiology
    • Incidence
      • 15% of acute wrist injuries
      • 60% of all carpal fracture
      • 8 per 100,000 females, 38 per 100,000 males
    • Demographics
      • 2 :1 male : female
      • most common in third decade of life
    • Anatomic location
      • percentage of fractures by scaphoid anatomic location
        • waist -65%
        • proximal third - 25%
        • distal third - 10%
          • Historically the distal pole is most common location in pediatrics due to ossification sequence, however more recently waist fractures have become most common
  • Etiology
    • Pathophysiology
      • pathoanatomy
        • most common mechanism of injury is axial load across a hyper-dorsiflexed, pronated and ulnarly-deviated wrist
        • common in contact sports
        • transverse fracture patterns are considered more stable than vertically or obliquely oriented fractures
    • Associated conditions
      • SNAC (Scaphoid Nonunion Advanced Collapse)
  • Anatomy
    • Osteology
      • complex 3-dimensional structure described as resembling a boat, skiff, and twisted peanut
      • oriented obliquely from extremity's long-axis (implications for advanced imaging techniques)
      • largest bone in proximal carpal row
      • > 75% of scaphoid bone is covered by articular cartilage
      • articulates with radius, lunate, trapezium, trapezoid, and capitate
    • Blood supply
      • major blood supply is dorsal carpal branch (branch of the radial artery)
        • enters scaphoid in a nonarticular ridge on the dorsal surface and supplies proximal 80% of scaphoid via retrograde blood flow
      • minor blood supply from superficial palmar arch (branch of volar radial artery)
        • enters distal tubercle and supplies distal 20% of scaphoid
      • creates vascular watershed and poor fracture healing environment
    • Biomechanics
      • link between proximal and distal carpal row
      • both intrinsic and extrinsic ligaments attach and surround the scaphoid
      • the scaphoid flexes with wrist flexion and radial deviation and extends during wrist extension and ulnar deviation (same as proximal row)
    • See Wrist Ligaments and Biomechanics for more detail
  • Classification
      • Herbert and Fisher Classification (based on fracture stability)
      • Type A
      • Stable, acute fractures
      • Type B
      • Unstable, acute fractures (distal oblique, complete waist, proximal pole, trans-scaphoid and perilunate associated fractures)
      • Type C
      • Delayed union characterized by cyst formation and fracture widening
      • Type D
      • Nonunion
      • Mayo classification (based on location of fracture line)
      • Type I
      • Distal tubercle fracture
      • Type II
      • Distal articular surface fracture
      • Type III
      • Distal third fracture
      • Type IV
      • Middle third fracture
      • Type V
      • Proximal third fracture
      • Russe Classification (based on fracture pattern)
      • Type I
      • Horizontal oblique fracture line
      • Type II
      • Transverse fracture line
      • Type III
      • Vertical oblique fracture line
  • Presentation
    • History
      • high or low energy fall onto outstretched hand
    • Symptoms
      • variable level of pain over wrist
    • Physical exam
      • inspection
        • wrist swelling
        • rarely any ecchymosis, hematoma, or gross deformity
      • motion
        • worsened wrist pain with circumduction
      • pain with resisted pronation
      • provocative tests
        • anatomic snuffbox tenderness dorsally
        • scaphoid tubercle tenderness volarly
        • scaphoid compression test
          • positive test when pain reproduced with axial load applied through thumb metacarpal
        • 87-100% sensitivity and 74% specificity when all three tests positive within 24 hours of injury
  • Imaging
    • Radiographs
      • recommended views
        • neutral rotation PA
        • lateral
        • semi-pronated (45°) oblique
        • scaphoid
          • 30 degree wrist extension, 20 degree ulnar deviation
          • waist fractures seen best
      • findings
        • if radiographs are negative (27%) and there is a high clinical suspicion
        • repeat radiographs in 14-21 days
    • Bone scan
      • indications
        • occult fractures in acute setting
      • sensitivity and specificity
        • specificity of 98%, and sensitivity of 100%, PPV 85% to 93% when done at 72 hours
    • MRI
      • indications
        • most sensitive for diagnosis occult fractures < 24 hours
        • immediate identification of fractures / ligamentous injuries
        • assessment of vascular status of bone (vascularity of proximal pole)
          • proximal pole AVN best determined on T1 sequences
      • sensitivity and specificity
        • approach 100% for occult fractures
    • CT scan with 1mm cuts along scaphoid axis
      • indications
        • best modality to evaluate fracture location, angulation, displacement, fragment size, extent of collapse, and progression of nonunion or union after surgery
      • sensitivity and specificity
        • 62% sensitivity and 87% specific for determining stability and fracture
        • less effective than bone scan and MRI to diagnose occult fracture
  • Treatment
    • Nonoperative
      • cast immobilization
        • indications
          • stable nondisplaced fracture (majority of fractures)
          • if patient has normal radiographs but there is a high level of suspicion can immobilize in thumb spica and reevaluate in 12 to 21 days
        • outcomes
          • scaphoid fractures with <1mm displacement have union rate of 90%
    • Operative
      • percutaneous screw fixation
        • indications
          • unstable fractures as shown by
            • proximal pole fractures
            • displacement > 1 mm without significant angulation or deformity
          • non-displaced waist fractures
            • to allow decreased time to union, faster return to work/sport, similar total costs compared to casting
        • outcomes
          • union rates of 90-95% with operative treatment of scaphoid fractures
            • CT scan is helpful for evaluation of union
      • open reduction internal fixation
        • indications
          • significantly displaced fracture patterns
          • 15° scaphoid humpback deformity
          • radiolunate angle > 15° (DISI)
          • intrascaphoid angle of > 35°
          • scaphoid fractures associated with perilunate dislocation
          • comminuted fractures
          • unstable vertical or oblique fractures
        • outcomes
          • accuracy of reduction correlated with rate of union
  • Technique
    • Cast immobilization
      • technique
        • start immobilization early
          • nonunion rates increase with delayed immobilization of > 4 weeks after injury
        • long arm spica vs short arm casting is controversial
          • no consensus
          • duration of casting depends on location of fracture and risk of nonunion
          • immobilization maintained until radiographic fracture healing demonstrated, usually no sooner than 8 weeks
          • may be required for up to 12-14 weeks for high-risk fracture patterns/patients
          • athletes should not return to play until imaging shows a healed fracture
        • may opt to augment with pulsed electromagnetic field (studies show beneficial in delayed union)
        • formal therapy following immobilization to regain range of motion
    • Percutaneous screw fixation
      • approach
        • dorsal approach
          • best for proximal pole fractures
          • care must be taken to avoid EPL tendon and to preserve the blood supply when entering the dorsal ridge
            • limit exposure to the proximal half of the scaphoid
          • percutaneous has higher risk of unrecognized screw penetration of subchondral bone
        • volar approach
          • indicated in waist and distal pole fractures
          • fractures with humpback flexion deformities
          • allows exposure of the entire scaphoid
          • avoids jeopardizing scaphoid blood supply
          • uses the interval between the FCR and the radial artery
          • careful capsule management to allow closure and restoration of RSC ligament
        • arthroscopic assisted approach
          • has also been described to aid in anatomic reduction
      • technique
        • precise wire placement in central axis to guide cannulated screw
        • do not violate scaphotrapeziotrapezoidal joint cartilage
        • rigidity is optimized by long screw placed down the central axis of the scaphoid
        • oblique fluoroscopic images to confirm placement and appropriate screw length
    • Open reduction internal fixation
      • approach
        • dorsal and volar approaches as above
      • technique
        • allows direct visualization and reduction at fracture site
        • screw placement as above
  • Complications
    • Scaphoid Nonunion
      • incidence
        • 5-10% following immobilization, higher rates for proximal pole fractures
      • risk factors
        • vertical oblique fracture pattern, displacement >1mm, advancing age, nicotine use
      • treatment
        • vascularized or nonvascularid bone grafting procedures
    • Osteonecrosis
      • incidence
        • 13-50% of all scaphoid fractures
        • many studies showing 100% in proximal fifth fractures with immobilization
    • Malunion
      • flexion of distal fragment and extension of proximal fragment due to pull of scapholunate interosseous ligament creating shortened bone with humpback deformity
      • treatment
        • no clear indications supporting operative versus non-operative treatment
    • Subchondral bone penetration with arthrosis due to prominent hardware
      • incidence
        • seen following mini-open fixation techniques
        • incidence has decreased with use of fluoroscopy
      • treatment
        • revision surgical fixation versus implant removal following union
    • SNAC wrist (scaphoid nonunion advanced collapse)
  • Prognosis
    • Incidence of AVN (without treatment) is directly correlated with proximity of fracture to proximal pole
      • proximal 5th AVN rate of 100%
      • proximal 3rd AVN rate of 33%
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