What is the distal radius?
The 2 forearm bones are the radius and ulna. They articulate at the elbow with the humerus bone, and at the wrist with the carpal or wrist bones. These 2 bones also form joints with each other at both the elbow and the wrist to allow the forearm to rotate. The distal radius is the term given to the area of the radius bone within 2-3cm of the wrist joint.
How is it injured?
Fractures of the distal radius occur usually with a fall onto the outstretched hand. Often, the tip of the ulna will fracture at the same time.
Who gets this injury?
The largest group of patients who get this injury are women over the age of 50. Bones are very strong and full of calcium in young patients up to around the age of 30-35. As people get older, generally their bones lose density at a low level rate. This process of losing the bone density is accelerated in women after menopause, causing the bones to become weaker faster than before menopause. This process can result in osteopaenia (loss of bone density on xray) or osteoporosis (loss of bone density at a higher level than most people). The second group of patients who get this fracture are young people, more commonly men, who have high energy injuries – injuries where they have fallen from a height or fallen at speed, such as coming off a bike or falling from a ladder. We call this distribution bimodal – younger higher energy patients and older osteopenic patients.
What happens when it breaks?
1) STABLE INJURY A stable injury is one where the bones stays in its usual position and has a very low risk of moving from this position, even if untreated. In many cases of distal radial fracture, although the bone fractures, there is no movement or displacement of the bone, and the soft tissues around the bone are not disrupted.
2) UNSTABLE INJURY When the injury is unstable, it means that the broken parts of the bone do not move together, and often there is a gap on the xray between the bone ends, or an abnormal angulation between the bone ends.
A good analogy is when a plate cracks – often you can see the crack, but the plate is still able to work as a plate. This is a stable crack. However if the crack breaks the plate, then the plate is in 2 pieces and cannot function as a plate until the crack is repaired (although with a plate, it would usually go in the bin!!). This would be an unstable crack.
What symptoms will I have?
Fractures of the distal radius produce immediate severe pain, swelling and often deformity of the wrist. It is usually very sore to move the wrist and fingers. Sometimes the fingers feel tingly or numb following a fracture.
What are the treatment options?
It is rare for a fracture of the distal radius not to heal with time. Surgeons have been arguing for decades over the best way of treating these fractures. We use evidence based on scientific studies to guide our recommendations for treatment. Best evidence currently tells us that:
1) Outcome following a distal radial fracture in elderly patients is the same whether or not the bone is fixed in position surgically. The definition of ‘elderly’ is the problem here! Many 60 year olds have active, young bone, and many have weaker bone. Certainly, by around 70, this rule applies to the majority of patients.
2) Outcome in younger patients is better if the fracture is put back into a position similar to the normal position. This can be done with a plaster, or with an operation using wires or a plate.
The aim of treatment is to convert an unstable injury into a stable injury. This can be done with:
– A plaster cast. The broken bone is manipulated under an anaesthetic block into a position more like the pre-injury position. This method is very commonly used. The benefit of this type of treatment is that no operation is required. The main risk is that as the swelling goes down, the position of the fracture ‘slips’ back to the post-injury position.
– An operation. At operation, the surgeon will again manipulate the bones back into position and fix them there with either some wires (these wires are a bit like barbeque skewers – they are relatively stiff with a pointed end to drill into the bone), or a plate. If a bone plate is used, a wound is made over the palm side of the wrist, and the plate inserted under the muscles and tendons.
Although surgery stabilises the bones and usually allows early movement, there are risks involved with surgery, and you can read more about these here. Although the surgeon will aim for a perfect position of the bones, this is not always achieved, and occasionally the fixation fails to hold the position of the bones. Late problems associated with the use of bone plates include tendon irritation or rupture, and the risks and benefits should be discussed with the surgeon before having this type of operation.
How long does it take for the bone to heal?
Most fractures of the distal radius heal within 6-12 weeks. Bone heals much faster than the soft tissues around the bone, and these can take many months to heal. Most people are able to use their hand for light everyday use by 4-6 weeks after their injury. By 3 months, the majority of people can do the majority of tasks, with the exception of heavy lifting / twisting movements. It takes around a full year, however, to recover from this injury and improvement can be ongoing up to 2-3 years after this injury.
Are there any complications of this injury?
There are 4 classical complications of a fracture of the distal radius:
1) Carpal tunnel syndrome. This can be a direct result of the injury, or a consequence of the shape of the bone changing slightly after this injury.
2) Malunion. A malunion occurs when the bone position is not maintained and the bone heals with a deformity. This is a very common complication of treatment for a distal radial fracture. The surgeon will discuss with you whether surgery is appropriate to improve the position of the bone, but a malunion usually does not impair normal function in the long term.
3) Rupture of the thumb tendon. The tendon responsible for straightening out the thumb runs in a tunnel at the back of the wrist, and is particularly prone to being damaged by the broken bone. It snaps in around 1-3% of patients. Sometimes other tendons compensate for this complication, but usually a simple operation is required to regain movement.
4) Complex regional pain syndrome (CRPS). This complication is a devastating condition where the hand and often the arm become painful, hypersensitive and very stiff. It often improves over the course of a year or 2 with physiotherapy, but usually leave a permanent functional impairment.
© Fife Hand Service 2020