Thumb Dislocations

MANUAL MINORS

Thumb dislocations occur when the joint surfaces of the bones separate, most commonly at the metacarpophalangeal (MCP) or interphalangeal (IP) joints. This injury is typically caused by severe hyperextension or abduction forces, such as falling onto the thumb or direct trauma. It presents with pain, visible deformity, and an inability to move the thumb.

Diagnosis

Diagnosis is based on clinical observation of deformity, pain, and swelling, along with the inability to move the thumb. X-rays confirm the diagnosis by revealing the displacement of joint surfaces and ruling out associated fractures.

Differential Diagnosis

Condition	Key Differences
First metacarpal fracture	Visible fracture line on X-rays, with localised pain and greater functional impairment.
Thumb sprain	Pain and swelling without evidence of joint displacement on X-rays.
Gamekeeper’s thumb	Ulnar collateral ligament injury, potentially with avulsion fracture.
Thumb subluxation	Partial joint displacement without complete separation of the bone surfaces.

Emergency Management

• Immediate immobilisation of the thumb in its deformed position to prevent further damage.

  
  

• Application of ice to reduce swelling and administration of analgesics or anti-inflammatories for pain relief.

  
  

• Closed reduction of the dislocation under local anaesthesia or sedation, using precise techniques to avoid additional injury.

  
  

• Post-reduction X-rays to confirm correct joint alignment.

  
  

• Immobilisation with a splint or cast to protect the joint during recovery.

  
  

Definitive Treatment

After reduction, the thumb should be immobilised for 2-4 weeks, depending on the severity. If the dislocation is unstable or accompanied by ligament injury, surgery may be required to repair the tissues and stabilise the joint. Post-reduction rehabilitation with physical therapy is essential to restore thumb mobility and strength.