Fracture, Scaphoid



Ovid: 5-Minute Sports Medicine Consult, The


Fracture, Scaphoid
Brent R. Becker
Keith A. Stuessi
Basics
  • Most commonly fractured of the 8 carpal bones of the hand
  • Usual mechanism of injury is a fall onto an outstretched hand
  • Scaphoid fractures, particularly fractures of the proximal pole, have an increased risk of nonunion.
  • Synonym: Fracture, carpal navicular
Epidemiology
  • Fractures of the carpal bones account for 6% of all fractures.
  • Fracture of the scaphoid accounts for 70% of all carpal fractures:
    • 75–80% of scaphoid fractures occur through the waist of the bone.
    • 15–20% through the proximal pole
    • 10–15% through the distal pole
  • Young adult males are the most common patient (children: Distal radial physis fails before scaphoid fracture; older adults: Distal radial metaphysis fails before scaphoid fracture).
Incidence
  • Incidence in athletes is unknown.
  • 4-fold greater incidence in men compared to women (1)
Etiology
  • Most commonly described mechanism is hyperextension of wrist with radial deviation and axial loading of scaphoid onto radial rim
  • Usually associated with falls, athletic injuries, or motor vehicle injuries
  • Increased risk of nonunion in proximal pole fractures due to tenuous blood supply
Diagnosis
History
  • Patients report falling on the extended wrist or other wrist trauma.
  • Pain at the wrist, near base of the 1st metacarpal
  • Pain located at the “anatomical snuffbox”: Area on radial side of wrist between extensor pollicis brevis and extensor pollicis longus
  • Pain described as deep and dull made worse with gripping or squeezing
Physical Exam
  • Tenderness in anatomical snuffbox (waist fracture or distal pole fracture):
    • Bordered dorsally by tendon of extensor pollicis longus and volarly by extensor pollicis brevis and abductor pollicis longus
    • Sensitivity 90%, specificity 40% (2)
    • False positives may occur by compression of a sensory branch of the radial nerve as it crosses the snuffbox.
  • Tenderness of scaphoid tubercle:
    • Extend patient wrist and apply pressure at proximal wrist crease
    • Sensitivity 87%, specificity 57% (2)
  • Scaphoid compression test: Axially/longitudinally compressing patient's thumb along a line of the 1st metacarpal:
    • Some studies show poor predictive value (2).
Diagnostic Tests & Interpretation
Imaging
  • 3 views of the wrist: Posteroanterior (PA), lateral, and “scaphoid” view, ie, anteroposterior view of wrist with 30 degrees supination and ulnar deviation
  • May request additional views: Radial oblique, ulnar oblique, and PA wrist with clenched fist in radial and ulnar deviation
  • Plain radiographs may be normal immediately after injury.
  • Fracture may become apparent 10–14 days after injury (immobilization allows demineralization of the fracture line).
  • Examine radiographs for evidence of the “Terry Thomas” sign (ie, widening of the scapholunate distance). Evidenced by >3 mm between the scaphoid and the lunate:
    • Indicates ligamentous injury to the scapholunate ligament
Bone scan:
  • Consider in patients with persistent snuffbox tenderness but negative plain radiographs
  • Cost-effective when compared to repeat radiographs (2)
  • Positive scan shows increased uptake at the scaphoid focally after 72 hr.
  • Excellent sensitivity (97%), but specificity (87%) is less than CT and MRI (3)
CT scan:
  • May be used to accurately help diagnose and delineate the fracture line and displacement
  • Sensitivity (93%) and specificity (99%) is similar to MRI (3).
MRI:
  • Consider when initial radiographs are negative and/or other ligamentous injury is suspected.
  • Sensitive (96%) and specificity (99%) (3)
  • Cost-effectiveness is unclear (2).
  • MRI shows diminished signal in T1-weighted and increased signal in T2-weighted images.

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Differential Diagnosis
  • Scapholunate dissociation
  • Distal radius fracture
  • Wrist sprain
  • Arthritis
Ongoing Care
  • Avascular necrosis of the proximal fracture fragment, leading to wrist dysfunction and early osteoarthritis
  • High incidence of fibrous nonunion at the fracture site (8–10%)
  • Frequent malunion
  • Carpal instability
  • Post-traumatic arthritis
Follow-Up Recommendations
  • Nondisplaced waist or distal pole fracture can be treated closed by primary care physician.
  • Refer patients with displaced scaphoid fracture.
  • Consider referring patient with proximal pole fracture (prone to nonunion and avascular necrosis).
  • Consider referring high-demand patients with nondisplaced fractures.
References
1. Rizzo M, Shin AY. Treatment of acute scaphoid fractures in the athlete. Curr Sports Med Rep. 2006;5:242–248.
2. Phillips TG, Reibach AM, Slomiany WP. Diagnosis and management of scaphoid fractures. Am Fam Physician. 2004;70:879–884.
3. Yin ZG, Zhang JB, Kan SL, et al. Diagnosing suspected scaphoid fractures: a systematic review and meta-analysis. Clin Orthop Relat Res. 2009.
4. Grewal R, King GJ. An evidence-based approach to the management of acute scaphoid fractures. J Hand Surg [Am]. 2009;34:732–734.
Additional Reading
Beeres FJ, Rhemrev SJ, den Hollander P, et al. Early magnetic resonance imaging compared with bone scintigraphy in suspected scaphoid fractures. J Bone Joint Surg Br. 2008;90:1205–1209.
Ram AN, Chung KC. Evidence-based management of acute nondisplaced scaphoid waist fractures. J Hand Surg [Am]. 2009;34:735–738.
Codes
ICD9
  • 814.01 Closed fracture of navicular (scaphoid) bone of wrist
  • 814.11 Open fracture of navicular (scaphoid) bone of wrist


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