DISTAL RADIUS FRACTURE
What is a Broken Wrist (aka Distal Radius Fracture) ?
A distal radius fracture is the most common wrist fracture and also one of the most common fractures of any kind. It occurs when someone falls onto an outstretched hand. Its most common in elderly people because its associated with osteoporosis (thinning of bones).
Typically the force of impact not only breaks the radius bone, but it also pushes the bone backward and out of position.
There are many variations of this injury. Of note, the crack sometimes enters the wrist joint, or sometimes the ulna (the other forearm bone) or the scaphoid (another wrist bone) breaks at the same time.
Although this is an injury most commonly seen in elderly, it can also occur in younger people, if there is an high energy accident (like falling off a ladder). In wrist fractures of younger people, the joint line is usually damaged more severely (because its a higher energy injury).
How is a Broken Wrist diagnosed?
The simple answer is "x-ray". However, we do not get x-rays of everyone that hurts their wrist.
So how do doctors know which injuries to get x-rays for?
Suspicion for this type of fracture arises from the history of the injury. It usually involves a specific event, and there is pain and swelling at the wrist. Inability to move the wrist is a good indicator to get an x-ray, as well as an obvious deformity of the wrist (the wrist will look bent out of place).
Often times the bone doesn't just break, it moves out of position. Doctors will look at how far the bone has moved on x-ray to decide how the injury should be treated. In fact, there are specific angles and distances that can be measured, which will tell doctors the likelihood that the wrist will return to normal. These measurements include "radial inclination", "radial height", "volar tilt", "articular congruity", and "ulnar deviance".
Once the fracture is identified, we will look at other surrounding bones, especially the scaphoid (the largest carapal bone, wrist bone) to ensure there are not other accompanying fractures. We also look for numbness and tingling in the hand, because fractures cause swelling and sometimes very swollen hands cause compression of the median nerve running through the carpal tunnel and you develop acute onset carpal tunnel syndrome.
There are classic fracture patterns that are seen with this fracture type.
How is a Broken Wrist treated?
Once identified, the best treatment depends on how badly the wrist is broken.
The wrist is usually straightened out in the emergency room, meaning if the bone moves out of position, its re-set, and then immobilized in a splint or cast.
The joint (articular congruity) is the most important thing to return to normal to prevent arthritis, and if there is asymmetry >2mm, theres almost a 100% risk of premature degeneration. Radial height loss changes the motion of wrist and causes loss of strength, loss of inclination causes decreased grip strength.
If these return to normal after the wrist is re-set, then treatment will be a splint for 2 weeks until the swelling goes down, then a cast for four more weeks.
Sometimes even if the wrist gets realigned perfectly, the broken bone is unstable, and it will separate again inside of the splint. Bad fracture have a higher risk of returning to its broken position. In fact, there are certain things that doctors can look at to predict the chance of this happening. These things include the amount of initial displacement (how far apart the bone fragments move), a persons age (older people have thinner bones where are less stable), the number of cracks in the bone ("comminution"), whether the break enters the wrist joint ("intraarticular"), and whether there are other injuries too (like a broken arm etc).
In cases where the broken bone cannot be held in a straight position, surgery is often useful. Surgery uses a small plate and screws to keep the radius bone straight while it has time to heal.
What is the long term outcome?
Low rate of long term disability when the broken bone is set, and held in the correct position.