Bennett's Fracture: Break At The Base of Your Thumb

Anatomy

By: Ehren Allen, PT/Certified Manual Therapist

The hand is composed of 5 long bones or “metacarpals” that connect the wrist bones to the finger bones or “phalanges”. The thumb consists of one metacarpal bone and two phalanges (proximal and distal). 

The base of the metacarpal bone articulates with the trapezium bone of the wrist, forming the Carpometacarpal (CMC) joint. 

A Bennett's fracture or Bennett, named after Edward Hallaran Bennett who first described the fracture, is an intra-articular fracture located at the base of the first metacarpal extending into the CMC joint. 

Bennett's Fracture X-ray.Image of a Bennett's Fracture.

A Bennett’s fracture is the most common fracture of the thumb. The CMC joint is a highly mobile joint that is responsible for the gripping and pinching actions of the hand. 

A Bennett's fracture can result in: 

  • thumb and wrist pain weakness
  • loss of motion or function

This can make it difficult to perform activities of daily living, homemaking tasks, and recreational activities.

Mechanism of Injury

A Bennett’s fracture usually occurs when there is a force applied upon a flexed metacarpal, such as punching a hard object or falling on an outstretched hand, and is usually associated with subluxation (partial dislocation) or dislocation of the thumb. 

This injury is common in athletes participating in boxing, football, rugby, and soccer (goalkeeper).

Bennetts Fracture Treatment

A formal evaluation should be performed by an upper extremity orthopedic physician to determine proper diagnosis and treatment. Physical examination and diagnostic imaging (x-ray) will confirm a Bennett’s fracture. 

Treatment options range from conservative to surgical interventions. Treatment depends largely upon the mechanism of injury, severity, displacement, and incongruity of the fracture. 

Anti-inflammatory medication and ice can help reduce pain and inflammation initially following the fracture. 

In most cases, closed reduction and immobilization via a thumb spica orthosis for 4-6 weeks can be effective at managing the fracture. 

Closed reduction is the manipulation of the fracture back into alignment without surgical incision. Closed reduction is not suitable for open or unstable fractures. 

If there is continuous CMC joint subluxation or greater than 1 mm of joint incongruity following closed reduction, surgical intervention is recommended.


Depending on the severity of the fracture, surgical treatment involves either closed reduction with percutaneous pinning or open reduction and internal fixation (ORIF). 

Closed reduction with percutaneous pinning involves first manipulating the fracture back into alignment then inserting pins into the thumb metacarpal and trapezium of the wrist to stabilize the fracture. 

In contrast, open reduction involves a surgical incision and incorporates the use of wires, screws, and plates for proper alignment and stability of the fracture to allow it to heal appropriately. 

Following closed reduction or surgery to repair a Bennett's fracture, the orthopedic physician may also prescribe a course of occupational or hand therapy. 

Immobilization of the thumb and wrist for a prolonged period of time can lead to stiffness and weakness. 

Skilled occupational therapy interventions will aim to: 

  • maximize functional ROM and strength 
  • address scar/edema management 
  • apply modalities as needed to allow patient to return to prior level of function with activities of daily living, homemaking tasks, and recreational activities


If you want more information about Bennetts Fracture Treatment, go to JOIonline.net or call JOI-2000 for an appointment.


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