Base of Thumb Fractures


35 year old male comes in after a fall whilst playing contact sport. He has pain and deformity to the thumb with gross swelling and bruising.


Thumb function constitutes 50% of overall hand function. Recognition, early diagnosis and treatment generally result in better functional outcomes after thumb injuries. 80% of thumb fractures involve the base of the thumb or metacarpal. The 1st metacarpal is the most commonly injured as it has no protection from adjacent bones and less stability.


  • History
    • Usually caused by an injury involving an axial force applied to the thumb whilst it is flexed.
    • In the younger age this is usually a sports injury or road traffic accident.
    • In the older age-group (>50 years) the injury is usually an accidental fall.
    • Immediate pain, swelling, bruising and limitation of movement following injury
  • Delayed presentations
    • Hyperextension deformity may be present with a history more in keeping with base of thumb osteoarthritis.
    • Swelling and bruising may have resolved with reduction in pain and partial restoration of function.


  • Look
    • Localised swelling and bruising
    • Deformity or asymmetry
    • Look for any skin breaches suggestive of open fracture (High risk of infection)
  • Feel
    • Localised tenderness over base of thumb
    • Check neurovascular status (thumb tip pink, warm, CRT<2s, sensation to light touch)
  • Move
    • Pain limiting ROM


Red Flags:

Skin overlying the fracture compromised = OPEN fracture


  • Imaging
  • X-ray Hand/Thumb (PA/Lateral/Oblique views)(Figure 1)
  • CT Thumb
    • Not routinely performed, useful to confirm joint subluxation or for pre-operative planning
    • Not typically available to primary care clinicians
  • MRI shoulder
    • Not routinely performed, useful if associated soft tissue injury suspected
    • Not typically available to primary care clinicians



  • Soft tissue injury


Based on fracture pattern (Figure 2)

  • Extra-articular (Figure 1a and b)
  • Oblique
  • Transverse
  • Intra-articular
  • Bennett (Figure 1c and d)
  • Rolando (Figure 1e)
  • Comminuted

Extra-articular Fracture

  • Usually at meta-diaphyseal junction
  • Flexor pollicis longus tends to pull the distal fragment into flexion
  • Abductor pollicis holds the proximal fragment in abduction

Bennett Fracture

  • Fracture line into the joint surface
  • Palmar ulna fragment held in place by strong anterior oblique (beak) ligament
  • Abductor pollicis longus pulls shaft radially and dorsally can leave the joint subluxed/dislocated

Rolando  Fracture

  • Fracture line into the joint surface
  • Y or T shaped fracture line
  • Multiple fragments

Figure 2



  • Closed reduction + thumb spica cast/splinting
  • Elevation
  • NSAIDs
  • Physiotherapy after immobilisation


  • Closed reduction + k-wire fixation
  • Open reduction + fixation with screws or plates
  • Distraction and external fixation

When to Refer

See treatment algorithm (figure 3)

Prognosis/Managing Expectations

  • Immobilisation for 4-6 weeks
  • Mobilisation and functional rehabilitation 3-4 months

Incidence of post-traumatic osteoarthritis unknown but higher risk with intra-articular base of thumb fractures

Treatment Algorithm


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