Scaphoid Fracture

Notes

Overview

Scaphoid fracture is the most common carpal bone fracture, accounting for ~60–70% of all carpal fractures. It occurs most frequently in young adults (15–40 years) following a fall on the outstretched hand (FOOSH). The scaphoid’s tenuous blood supply predisposes to non-union and avascular necrosis, especially in proximal fractures. Early recognition is essential as delayed or missed diagnosis is common and may lead to long-term disability.

Definition

FOOSH: “Fall On Outstretched Hand,” common mechanism of wrist injuries.
Anatomical snuffbox: Depression between tendons of extensor pollicis longus and brevis; tenderness here is pathognomonic for scaphoid fracture.
Avascular necrosis (AVN): Bone death due to disruption of blood supply. A common site for avascular necrosis is to the scaphoid bone as well as the hip.
Non-union: Failure of bone fragments to heal within expected timeframe.

Anatomy & Physiology

Scaphoid: Boat-shaped carpal bone on radial side of wrist; articulates with radius, trapezium, trapezoid, capitate, lunate.
Blood supply: Retrograde from dorsal carpal branch of radial artery → enters distally → supplies proximal pole last.
Clinical relevance: Proximal fractures at highest risk of AVN due to poor vascularity.

Proximal pole = poor healing → high risk AVN.

Aetiology and Risk Factors

Aetiology

Direct trauma: FOOSH (most common).
Less common: Punching injuries, direct blow to wrist.

Risk Factors

Young, active adults (sports injuries, falls).
Males > females.
High-energy trauma (e.g., motor vehicle accidents).

Pathophysiology

FOOSH → axial load transmitted through radial styloid.
Scaphoid bone compressed against distal radius.
Fracture occurs, most often at the waist (70%), less at proximal pole (20%) or distal pole (10%).
Retrograde blood supply disrupted → risk of delayed healing or AVN (especially proximal).

Mechanism + vascular anatomy explains why scaphoid fracture is high risk despite being a “small bone.”

Clinical Manifestations

Wrist pain after FOOSH.
Clinical examination
- Anatomical snuffbox tenderness (classic).
- Tenderness over scaphoid tubercle (volar wrist).
- Pain with axial compression of thumb.
- ↓ wrist motion, swelling may be minimal.
Often subtle → patients may continue to use wrist.

Snuffbox tenderness = scaphoid fracture until proven otherwise.

Diagnosis

Clinical suspicion: FOOSH + snuffbox tenderness.
X-ray (wrist, scaphoid views): May be normal initially (up to 30% missed).
Repeat imaging: X-ray after 10–14 days if initial negative.
MRI (gold standard): Detects occult fractures within 24 hours.
CT scan: Best for assessing union and fracture displacement.

Differential Diagnosis

Condition	Differentiating Features
Distal radius fracture	More swelling/deformity, visible on plain films
Wrist sprain	No bony tenderness, normal MRI
Scapholunate ligament injury	Pain on Watson’s test, widening on imaging

Always immobilise if suspicion is high, even with negative initial X-ray.

Classification

Distal pole (~10%) – good healing, low risk AVN.
Waist (~70%) – most common.
Proximal pole (~20%) – poor healing, high risk AVN.

Treatment

Non-displaced distal/waist fractures: Immobilisation in thumb spica cast for 6–12 weeks.
Proximal or displaced fractures: Surgical fixation (percutaneous screw or open reduction).
Follow-up imaging: CT/MRI for union assessment.
Rehabilitation: Gradual mobilisation once union confirmed.

Distal = cast; Proximal = screw.

Complications & Prognosis

Complications

Non-union (5–15%).
Avascular necrosis (esp. proximal pole).
Osteoarthritis (SNAC wrist – Scaphoid Non-union Advanced Collapse).
Chronic pain, stiffness, ↓ grip strength.

Prognosis

Good if treated early
Poor outcomes with delayed diagnosis.

References

Gelberman RH, Menon J. The vascularity of the scaphoid bone. J Hand Surg Am. 1980;5(5):508–13.
Yin ZG, Zhang JB, Kan SL, et al. Diagnostic accuracy of imaging modalities for suspected scaphoid fractures: meta-analysis. BMJ. 2012;344:e3052.
Fowler JR, Hughes TB. Scaphoid fractures. Clin Sports Med. 2015;34(1):37–50.
Ibrahim T, Qureshi A, Sutton AJ, et al. Surgical vs non-surgical treatment of acute scaphoid fractures: systematic review and meta-analysis. Cochrane Database Syst Rev. 2008;(4):CD006770.
Buijze GA, Ochtman L, Ring D. Management of scaphoid fractures in adults: what’s new? Injury. 2010;41(11):1120–8.