Are scaphoid fractures common?

Carpal fractures account for about 5% of all fractures, and among them the scaphoid fracture is the most common, making up about 70% of carpal fractures. Roughly 60% occur in the waist, with about 20% each in the proximal and distal poles. The incidence is higher in men than in women.

How does a scaphoid fracture usually happen?

The classic mechanism is an axial load applied to a hyperextended and radially deviated wrist, typically during a fall onto an outstretched hand with the weight pressing on the palm. It can also occur during sports or car accidents.

Who is more likely to get a scaphoid fracture?

Young men aged 20 to 30 are at higher risk, as are people involved in high-impact or fall-prone sports such as basketball, football, skiing, and cycling. Some research suggests that wearing wrist guards during activities like inline skating, skateboarding, and skiing may help reduce the chance of wrist fractures.

What symptoms occur after the injury?

The main symptom is wrist pain, especially near the base of the thumb, and the wrist may swell after the injury. Pain may worsen when moving the thumb or wrist and when pinching, gripping, pushing, or pulling objects.

How does a physician check for a scaphoid fracture?

The physical examination includes anatomical snuffbox tenderness, scaphoid tubercle tenderness, and the axial load test. Clinical examination has high sensitivity but lower specificity, and initial X-rays may also miss the fracture, so follow-up radiographs at 10 to 14 days or an MRI or CT are advised when a fracture is suspected.

Scaphoid Fracture Explained: The Most Common Hidden Danger Among the Carpal Bones

The word scaphoid comes from the Greek for boat. The scaphoid is relatively long and curved, shaped somewhat like a boat, and sits just beyond the distal radius, playing an important role in wrist motion and stability. It is the most commonly fractured of the carpal bones, and fractures can occur at three anatomical sites: proximal pole, waist, and distal pole. The usual mechanism is wrist hyperextension during a fall, and proximal fractures carry a higher risk of poor healing (nonunion).

This is mainly because the scaphoid’s blood supply is retrograde: blood enters the part of the scaphoid closest to the thumb (the distal pole) and then flows toward the part closest to the body (the proximal pole). As a result, distal scaphoid fractures heal much faster than proximal ones. In fact, a proximal scaphoid fracture can completely interrupt the blood supply, causing part of the scaphoid to become necrotic or die. This phenomenon is called avascular necrosis and can cause long-term problems in the wrist.

A scaphoid fracture usually happens during a fall onto an outstretched hand, with the weight pressing on the palm. In such a fall, the larger forearm bone (the radius) may also fracture, depending on the position of the hand at landing. The injury can also occur during sports activities or car collisions.

Epidemiology

Carpal fractures account for 5% of all fractures.
The scaphoid fracture is the most common carpal fracture, making up 70%:
- 60% occur in the waist
- 20% occur in the proximal pole
- 20% occur in the distal pole
The incidence is highest in men aged 20 to 24, and it is less common in children and the elderly.
- In children, a scaphoid fracture is more often replaced by a distal radial growth plate fracture (Salter-Harris type 1 and type 2 fractures).
- In older adults, a scaphoid fracture is more often replaced by a distal radius fracture.
Incidence:
Overall, the incidence is higher in men than in women.
It is estimated that about 1 in every 100 college rugby players sustains a scaphoid fracture.

Etiology

Classic mechanism of injury:
- An axial load applied to a hyperextended and radially deviated wrist.

Risk Factors

Age and sex:
- Men (especially young people aged 20 to 30) are at higher risk of scaphoid fracture.
Type of activity:
- High-impact sports or those involving falls, such as basketball, football, skiing, and cycling.
- Some research suggests that using wrist guards during high-energy activities such as inline skating, skateboarding, and skiing may help reduce the chance of fractures around the wrist.
Personal characteristics:
- Reduced bone density (although this is mentioned less often in scaphoid fractures).
Occupation:
- Jobs where the wrist is frequently under stress or falls are possible, such as construction workers or athletes.

History

Chief complaint
- Pain in the wrist (especially near the base of the thumb)
- Wrist swelling may accompany the injury.
- Pain may be quite severe when moving the thumb or wrist, or when trying to pinch, grip, push, or pull something.
Typical presentation
- The injury usually results from wrist hyperextension during a fall.
- The patient may recall feeling severe pain when the palm hit the ground.
Relevant history
Any past history of similar wrist injury or fracture
Whether the person engages in high-risk activities

Physical Examination

Main examination steps
1. Anatomical snuffbox tenderness:
  - Press on the snuffbox region on the lateral side of the thumb to check for pain.
2. Scaphoid tubercle tenderness:
  - Press on the scaphoid tubercle on the palmar side of the wrist to check for tenderness.
3. Axial load test:
  - Grasp the patient’s thumb and apply axial pressure to check for a pain response.
Note:
Although clinical examination has high sensitivity, its specificity is lower.
At the first visit, the X-ray may fail to detect the fracture.

Diagnostic Tools

Imaging studies:
1. X-ray:
  - The first-line examination tool.
  - If a fracture is suspected but the initial images are normal, repeat radiographs 10 to 14 days later are advised.
2. MRI:
  - 80% sensitivity and 100% specificity; consider it when the X-ray does not detect a fracture.
  - Suitable for early diagnosis and assessing blood flow.
3. CT:
  - Used to confirm the extent of the fracture and plan surgery; 93% sensitivity and 99% specificity.
Other tools:
A bone scan can serve as an adjunct tool, with 98% specificity and 100% sensitivity.

Fracture Classification

Many classifications are used for scaphoid fractures; based on their clinical nature there are at least three.

The Herbert classification is based on fracture stability. An unstable fracture is one with displacement greater than 1 mm between fragments or angulation greater than 15 degrees.
The Mayo classification, based on the location of the fracture line, divides scaphoid fractures into proximal (10%), middle (70%), and distal (20%).
Russe’s anatomical classification is based on the fracture pattern and can predict the tendency toward fracture healing. It distinguishes between horizontal oblique, transverse, and vertical oblique fracture lines.

Initial Treatment

Conservative treatment
- For stable fractures or patients with a suspected scaphoid fracture:
  - Immobilize with a short-arm thumb spica cast.
  - Follow-up and imaging are advised within 10 to 14 days.
  - Scaphoid fractures displaced less than 1 mm have a healing rate of 90%.
Surgical considerations
- For waist or proximal fractures, and/or if the fracture is displaced, surgery may be advised.
- Common procedures include screw fixation.
Medication
- Used to relieve pain and reduce the inflammatory response.
- Common choices include ibuprofen or naproxen.
- Acetaminophen can be used when pain is milder.
Antibiotics (used only after surgery or when the risk of infection is increased):
- Used to prevent infection after surgery.
- Chosen according to the individual patient’s situation and the type of surgery.
Rehabilitation
- Begins after the cast or brace is removed, to restore wrist range of motion and strength.
- Includes passive and active exercises, grip strength training, and resistance training.
Bracing
- In some unstable or delayed-healing cases, a specially designed wrist brace can provide ongoing support.
Bone stimulation therapy
- Suitable for patients with delayed healing or limited retrograde blood supply.
- Includes low-intensity pulsed ultrasound (LIPUS) or electromagnetic stimulation.
- There is relatively little research on this.

Surgery

Indications
- Fracture displacement greater than 1 mm or multiple bone fragments
- Proximal fracture
- Poor healing or nonunion after conservative treatment
Common surgical approaches
1. Closed reduction and internal fixation (CRIF):
  - Percutaneous screw fixation is often used.
  - Minimally invasive, with faster recovery.
2. Open reduction and internal fixation (ORIF):
  - Suitable for complex fractures or severe displacement.
  - The fracture site is directly observed during surgery.
Postoperative monitoring
- Cast immobilization may be needed for 6 to 12 weeks after surgery, usually not less than 8 weeks.
- Regular imaging to monitor the healing process.
- For high-risk fracture patterns or patients, healing can take as long as 12 to 14 weeks.

Follow-up

Regular follow-up
- Patients treated conservatively need clinical and imaging examination after 4 to 6 weeks.
- Surgical patients need suture removal and reassessment within 2 weeks after surgery.
Long-term follow-up
Continued monitoring to confirm complete healing
Preventively reducing the risk of future wrist injury, for example by using appropriate protective equipment

Prognosis

Influencing factors
- Fracture location:
  - Waist and distal fractures have high healing rates.
  - Proximal fractures have a higher rate of poor healing due to limited blood supply.
- Timing of treatment:
  - Early diagnosis and intervention can markedly improve the prognosis.
Complications
- Nonunion, 5 to 10% after fixation, with a higher rate in proximal fractures
- Osteoarthritis
- Avascular necrosis (especially in proximal pole fractures), 13 to 50% of all scaphoid fractures
Functional recovery
Most patients can return to normal activities after complete healing.
High-demand athletes may need a longer recovery period.