Dr. Kevin Yip

Dr Kevin Yip
Orthopaedic Surgeon
MBBS(UK), FRCS(EDIN), FAM(SING), FHKCOS(ORTHO)

Featured on Channel NewsAsia

Scaphoid Fracture

Basics
Description
  • Fracture of the most radial (thumb side) of the carpal bones, usually as a result of a dorsiflexion injury to the wrist
  • The most common of the carpal fractures, estimated at 60%
  • Frequent problems include delayed diagnosis and nonunion.
  • Classification:
    • Chronologically: Acute or chronic
    • Anatomically: In the proximal, middle, or distal third
  • Displaced or nondisplaced
  • Direction: Transverse or oblique
  • By mechanism: High-energy (e.g., motor vehicle accident) or simple, low-energy fall
  • Simple fracture or complicated fracture with associated ligament injury or dislocation.
  • Synonym: Navicular fracture
General Prevention
Wear wrist protectors during high-risk activities such as rollerblading and in-line skating.
Epidemiology
Incidence
  • In 1 study, the annual fracture rate was 4.3 per 10,000 people, the average age was 25 years, and 82% occurred in males.
  • Scaphoid fractures account for ~2% of all fractures and 11% of hand fractures.
  • 2nd most common fracture of the wrist area after the distal radius
  • Rare in children
Prevalence
Usually an injury of young adults (males more commonly than females, probably because of activity level) after a fall, athletic injury, or motor vehicle accident.
Risk Factors
  • Contact sports
  • Rollerblading and in-line skating
  • Risk factors for nonunion:
    • Proximal pole fracture
    • Distal oblique or vertical fracture
    • Large displacement of the fracture
    • High-energy injury
Pathophysiology
  • The major blood supply to the proximal pole enters the bone through the distal 1/3 of the bone.
  • Vessel disruption causes compromise of the blood supply to the proximal pole.
Etiology
  • An axial force impacting on an outstretched hand
  • The scaphoid acts as a bridge between the proximal and distal rows of the carpus, making it vulnerable to fracture.
Diagnosis
Signs and Symptoms
History
  • Pain or clicking with wrist motion
  • The clinician must have a high index of suspicion to avoid missing the injury.
  • Patients occasionally present late (months or even years after the injury) with persistent ache, weakness, or clicking.
Physical Exam
  • Pain with wrist motion is common.
  • Swelling is variable because the fracture may or may not produce much bleeding.
  • Typically, palpate the snuffbox region (between the short and long extensor tendons to the thumb) and compare the findings with those of the uninjured side.
    • If tenderness is found here, presume that the patient has a fracture until proven otherwise.
Tests
Lab
No laboratory tests aid in the diagnosis.
Imaging
  • Radiography:
    • Posteroanterior, lateral, pronated oblique, and ulnar deviated posteroanterior radiographs of the wrist (scaphoid views)
    • Displacement of the normal fat plane on the volar surface of the navicular is suggestive of injury.
    • Carefully scrutinize radiographs for signs of ligament disruption and carpal dislocation.
  • If plain radiographs are negative but examination is suggestive of fracture, additional imaging is indicated, including:
    • Bone scan (in acute phase)
    • CT scan with 3D reconstruction
    • MRI, which is becoming the standard test because results are obtained quickly
Differential Diagnosis
  • Ligament injury or sprain
  • Perilunate dislocation
  • Distal radius fracture
  • Wrist instability
Treatment
General Measures
  • Immobilize the wrist in a thumb spica splint for 2 weeks if clinical suspicion of a fracture exists, even if a fracture is not seen on initial radiographs.
  • The type of splint or cast used is controversial; recommendations range from an above-the-elbow thumb spica cast to a below-the-elbow cast that does not immobilize the thumb.
  • Radiographs should be repeated at 10-14 days, at which time the fracture edges may be better seen.
  • For nondisplaced fractures, the patient should be placed in a below-the-elbow thumb-spica cast for 6-8 weeks and then reassessed clinically and radiographically.
  • Displaced fractures and proximal pole fractures require surgery.
  • Fractures in competitive athletes may be treated surgically to allow for earlier return to activity.
Activity
Heavy lifting or sports activities should be avoided until the fracture is healed and the patient is pain free.
Special Therapy
Physical Therapy
Physical therapy maintains finger ROM during immobilization and helps regain wrist motion after immobilization.
Surgery
  • Displaced fractures should be treated with reduction and screw fixation.
    • Cannulated screws that are headless and have variable threads currently are used for fixation.
    • These screws can gain compression of the fracture site without protrusion of the screw from the edge of the bone.
    • The use of a cannulated screw with a guide wire aids in correct screw placement.
    • Cannulated screws may be placed percutaneously.
  • Chronic fractures or nonunions should be treated with reduction and fixation plus bone grafting.
  • Salvage procedures for late-stage arthritis seen after untreated fractures include excision of the proximal row of carpal bones or partial wrist fusion.
Follow-up
Disposition
Issues for Referral
  • Displaced fractures
  • Associated fractures and dislocations
  • High-energy injuries
Prognosis
  • >90% of nondisplaced fractures heal
  • No benefit has been found for treating nondisplaced fractures with surgery.
  • No differences have been found between the dorsal and volar approach to scaphoid fixation.
  • Displaced fractures:
    • Higher nonunion rate if treated closed
    • Good outcomes with surgical reduction and fixation
  • Treatment of scaphoid nonunions with vascularized bone grafting and internal fixation seems to have the highest rate of healing.
Complications
  • Nonunion
  • AVN of the proximal pole
  • Reflex sympathetic dystrophy
  • Arthritis
  • Wrist instability
Patient Monitoring
Patients with acute fractures are reviewed clinically and radiographically every 2-4 weeks until the fracture is healed and rehabilitation has been completed.
Miscellaneous
Codes
ICD9-CM
814.01 Scaphoid fracture
Patient Teaching
  • Patients should be informed of the difficulty of making the diagnosis of an acute fracture and the need for prophylactic immobilization if snuffbox tenderness is present.
  • The risk of delayed union or nonunion should be discussed.
Activity
Patients should be advised not to attempt pushing or lifting while wearing a cast.
Prevention
Wrist protectors are thought to prevent wrist injury and should be used for rollerblading or in-line skating.
FAQ
Q: How is a scaphoid fracture diagnosed?
A: Patients with traumatic wrist pain should be assessed carefully for fracture. Good-quality radiographs should be taken acutely. If negative, the patient should be immobilized and then reassessed in 2 weeks or assessed with MRI scanning.
Q: Why is it important that nondisplaced scaphoid fractures be diagnosed?
A: If untreated, nondisplaced fractures may become displaced and lead to scaphoid nonunion, requiring surgery. When nondisplaced fractures are treated with immobilization, results are excellent.

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