Scaphoid fracture

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Scaphoid fracture
Classification and external resources
Scaphoid waist fracture.gif
ICD-10 S62.0
ICD-9 814.x1
eMedicine emerg/844 radio/747 plastic/318 pmr/127

A scaphoid fracture, a fracture of the scaphoid bone also known as the carpal navicular, is the most common type of carpal bone fracture.[1] Scaphoid fractures usually cause pain at the base of the thumb accompanied by swelling in the same area. Scaphoid fractures usually cause pain and sensitivity to palpation in the anatomic snuffbox at the base of the thumb accompanied by swelling in the same area. These are also called navicular fractures (the scaphoid also being called the carpal navicular) as navicular is the traditional name for the scaphoid bone, although this can be confused with the navicular in the foot. Treatment depends on the location of the fracture.

Fractures of scaphoid can occur either with direct axial compression or with hyperextension of the wrist, such as a fall on the palm on an outstretched hand. The most common classification of scaphoid fractures categorizes them by location: distal third (distal pole), central third (waist) and proximal third (proximal pole). [2]

Diagnosis[edit]

Clinically patients present with snuff box tenderness. Focal tenderness is usually present in one of three places: 1) volar prominence at the distal wrist for distal pole fractures; 2) anatomic snuff box for waist or midbody fractures; 3) distal to Lister's tubercle for proximal pole fractures. [3]

Scaphoid fractures are often diagnosed by X-rays. However not all fractures are apparent initially. Therefore people with tenderness over the scaphoid (those who exhibit pain to pressure in the anatomic snuff box ) are often casted for 7–10 days at which point a second set of X-rays is taken. If there was a hairline fracture, healing will now be apparent. Even then a fracture may not be apparent. A CT Scan can then be used to evaluate the scaphoid with greater resolution. Fractures can take between 6 and 12 weeks of casting to heal. The Scaphoid receives its blood supply primarily from lateral and distal branches of the radial artery. Blood flows from the top/distal end of the bone in a retrograde fashion down to the proximal pole; if this blood flow is disrupted by a fracture, the bone may not heal. Surgery is necessary at this point to mechanically mend the bone together.

The use of MRI, if available, is preferred over CT and can give one an immediate diagnosis.[4] Bone scintigraphy is also an effective method for diagnosis fracture which do not appear on Xray.[5]

Complications[edit]

Scaphoid pseudarthrosis, before and after treatment with Herbert screw.

Avascular necrosis (AVN) is a common complication of a scaphoid fracture. Risk of AVN depends on the location of the fracture.

  • Fractures in the proximal 1/3 have a high incidence of AVN (~30%)
  • Waist fractures in the middle 1/3 is the most frequent fracture site and has moderate risk of AVN.
  • Fractures in the distal 1/3 are rarely complicated by AVN.

Non union can also occur from undiagnosed or undertreated scaphoid fractures. Arterial flow to the scaphoid enters via the distal pole and travels to the proximal pole. This blood supply is tenuous, increasing the risk of nonunion, particularly with fractures at the wrist and proximal end. [6] If not treated correctly non-union of the scaphoid fracture can lead to wrist osteoarthritis.

Treatment[edit]

Treatment of scaphoid fractures is guided by the location in the bone of the fracture (proximal, waist, distal), displacement (or instability) of the fracture, and patient tolerance for cast immobilization.

Non displaced or minimally displaced waist and distal fractures have a high rate of union with closed cast management. The choice of short arm, short arm thumb spica or long arm cast is debated in the medical literature and no clear consensus or proof of the benefit of one type of casting or another has been shown; although it is generally accepted to use a short arm or short arm thumb spica for non displaced fractures. Non displaced or minimally displaced fracture can also be treated with percutaneous or minimal incision surgery which if performed correctly has a high union rate, low morbidity and faster return to activity than closed cast management.[7]

Prevention[edit]

In 2006 Knox, a British manufacturer of impact protection for use in extreme sports, patented the SPS (scaphoid protection system). Designed for motorcyclists, SPS offers protection against common scaphoid injuries caused either by a compression fracture or by hyper extension when a glove palm made contact with the road. SPS consists of two low-friction pads positioned on the palm of each glove designed to eliminate the ‘grab’ effect and allowing the hand to slide. In 2012 Knox introduced SPS for mountain biking and cycling applications too. SPS has been adopted by many brands of motorcycle glove[8]

Athletes with fracture[edit]

Several professional athletes have suffered from this injury such as multiple World Champion cyclist Tony Martin, baseball player Ryan Lavarnway, ice hockey player Patrick Kane, basketball player Kendall Marshall, basketball player Jared Jeffries and Louisville Cardinals Center Gorgui Dieng

Epidemiology[edit]

Fractures of the scaphoid are common in young males. [9] :188

References[edit]

External links[edit]