Fracture, Scaphoid

By admin On Sep 17, 2023

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.

P.251

Differential Diagnosis

Scapholunate dissociation
Distal radius fracture
Wrist sprain
Arthritis

Treatment

Scaphoid fractures or suspected fractures with negative radiographs (2)[C]:

Immobilize in a thumb spica splint
Sling for comfort
Ice and elevation

Medication

Tylenol or NSAIDs as needed
Narcotics for breakthrough pain

Additional Treatment

Classification systems exist (Herbert, Mayo, etc.); however these classifications are not prognostic.
<1 mm separation of the fracture is generally considered nondisplaced (1).
Most nondisplaced fractures can be treated successfully with cast immobilization (1,2,4)[B].
Time to fracture union varies by location:
- Distal pole (6 wks) < Waist (12 wks) < Proximal pole (3–6 mos) (1)
Thumb immobilization does not appear to reduce healing time or increase the risk of nonunion (2)[B].
Long arm cast (vs short arm) may decrease healing time but does not improve nonunion rates (1,2,4)[C].
Displaced fractures should be referred for surgical fixation (1,2)[B].

Additional Therapies

Associated injuries include fracture of the distal radius, radial head, and lunate; soft tissue ligamentous injury leading to scapholunate dissociation; and possible injury to the median nerve
Postoperative or postcasting hand therapy

Surgery/Other Procedures

Surgical intervention should be undertaken for displaced fractures (1,2,4)[B].
Also consider surgery for nondisplaced fractures in high-demand athletes/patients where the necessary length of casting would interfere significantly with competition, training, or work (1)[C].
Multiple surgical techniques can be used (dorsal open reduction internal fixation [ORIF], volar ORIF, percutaneous, arthroscopic assisted):
- No current evidence to suggest one technique is superior:
  - Each has advantages and disadvantages.
- Surgeon preference and experience is often the deciding factor in operative technique.

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