What is a Bennett’s fracture?
A Bennett's fracture is the term for a fracture and dislocation of the base of the thumb, specifically the joint where the first metacarpal bone meets the carpal bones of the wrist called the carpometacarpal joint. The metacarpal bones connect your carpal bones to your phalanges (fingers and thumb), which are individually divided into three parts: distal, middle and proximal. In the case of a Bennett’s fracture it is the proximal bone that fractures. The lower position of the fracture ensures that in almost all cases there is a degree of dislocation to the thumb.
Why and when do Bennett’s fractures happen?
Bennett’s fractures are most commonly the result of a traumatic downwards force through the thumb. This is most commonly seen in boxers after punching an opponent’s skull or in individuals who have punched a wall. It is also a common injury in cyclist falls in particular, mountain biking as the thumb stays extended and wrapped around the handle bar. Most contact sports can be responsible for a Bennett’s fracture including rugby, American football, hockey, and basketball.
What does a Bennett’s fracture feel like?
A Bennett's fracture from trauma causes a very intense immediate sharp pain around the fracture site at the base of the thumb. The sharp pain often radiates up into the forearm and across into the wrist and hand. The fracture is often accompanied by swelling and bruising around the thumb and wrist. Due to the combination of fracture and dislocation the base of the thumb may look slightly deformed, limp and out of alignment. The pain levels will be aggravated by most hand or wrist movements this makes using the effected hand excruciating. The intense pain after a break will last for several hours which will be aggravated or prolonged by any treatment options like manipulation or traction. Post-surgery or after treatment when the bone starts to heal there will be a dull continuous ache from the swelling and healing process that will last weeks to months. During the healing process the bone is trying to knit together and re-unite, this stage can be quite painful and it is very important to rest through this stage to ensure that the bone reconnects properly. The soft tissue surrounding the fracture also starts to form scar tissue to bind everything together allowing the structure to try and restore its original state and function.
How is a Bennett’s fracture diagnosed?
Patients may be taken to A&E and a full examination will be done to rule out any additional injuries or complications like nerve damage or infection. Your doctor will order an X-ray of the thumb to confirm the diagnosis and identify the exact location of the fracture and the extent of the dislocation. Occasionally, if the extent of the fracture isn’t fully visible on an X-ray then an MRI or a CT scan will be ordered as this will give a more detailed view of the fractured site although this is rarely needed for a Bennett’s fracture. Doctors may also use an MRI scan to assess whether the pain felt after trauma is coming from injury to the wrist and hand muscles, ligaments or joint capsules and not indeed from a fracture. The occurrence of a Bennett’s fracture from mild trauma may prompt doctors to investigate for any underlying bone weakening conditions like osteoporosis.
What treatment options are available for Bennett’s fractures?
The treatment options and healing times for Bennett’s fractures vary depending on the position of the fracture and severity of the dislocation and also on the complications from any additional injuries like infection with open fractures. In most cases doctors recommend surgical fixation to stabilise the fracture this is due to a high incidence of long term thumb instability problems. Traction or manipulation may be used to correct the position of the fractured and dislocated bone and a splint or a cast will be used to reinforce and stabilise the fracture until it is well healed. Patients will initially have to rest and avoid using the effected hand whilst recovering. The doctor will most likely prescribe anti-inflammatory medication and painkillers for pain relief and to reduce any swelling. A Bennett’s fracture can take anything from 8 -12 weeks to heal if not longer for more severe breaks. Patients will be referred through to a physiotherapist who will provide exercises to strengthen the hand to aid the healing process. Fluctuating pain levels will be experienced throughout the healing process however most of the discomfort towards the end of the healing process comes from stiffness levels caused by long term immobility. The rehabilitation exercises as well as massage and some manipulative therapies can aid in recovering your thumb, wrist or hand strength and flexibility. There are also great products to use at home to rebuild thumb strength such as therapeutic putty and therapy balls.