Carpal Bone Fractures of the Wrist
Fractures of the small wrist bones, especially the scaphoid, may not show on the first X-ray and can be missed. Early diagnosis lowers the risk of non-union.
The wrist is made up of eight small bones (the carpal bones) arranged in two rows between the forearm bones and the hand. Fractures of these bones usually happen after a fall onto an outstretched hand. The most commonly fractured carpal bone is the scaphoid. Because of its blood supply, scaphoid fractures are prone to healing problems and are often missed.
Symptoms
- Pain and swelling in the wrist, especially on the thumb side
- Tenderness in the hollow at the base of the thumb (the anatomical snuffbox)
- Pain when gripping and bending the wrist
- Symptoms can be mild and mistaken for a sprain
Diagnosis
Carpal fractures do not always show on the first X-ray. If a scaphoid fracture is suspected but the X-ray is normal, the wrist is protected and assessed with MRI or CT. MRI is the most valuable test for showing hidden fractures early.
Treatment
Casting
Some undisplaced fractures of the waist of the scaphoid can be treated in a cast that includes the thumb. Healing can take several weeks to a few months and is followed with imaging.
Surgery
Screw fixation may be recommended for displaced fractures, fractures of the upper pole of the scaphoid, delayed union or non-union, and for patients who need to return to work or sport quickly. In suitable fractures, a single screw is placed through a small incision under imaging guidance. Non-unions may need bone grafting.
Other carpal bones
Fractures of the triquetrum, hamate and other carpal bones are treated with a cast or surgery depending on the fracture. Associated ligament injuries are also assessed.
What happens without treatment?
Missed or untreated scaphoid fractures may not heal. A non-union gradually disturbs the balance between the wrist bones and can lead to wrist arthritis over the years.
First steps after a wrist injury
If there is pain and swelling after a fall on the wrist, keep the wrist still, apply ice and keep the arm raised. Waiting a few days thinking “it’s just a sprain” can delay diagnosis, especially of scaphoid fractures. If there is tenderness at the base of the thumb, assessment is important even if the first X-ray is normal.
Why does the scaphoid heal poorly?
Blood reaches the scaphoid mostly from one end and flows towards the other. Because a fracture can cut this flow, part of the bone may not be nourished well enough, especially in fractures of the upper pole. This can lead to delayed healing, non-union and sometimes death of part of the bone (avascular necrosis). Scaphoid fractures are therefore followed with regular imaging.
Ligament injuries
Even without a fracture, a fall on the wrist can tear the ligaments between the carpal bones, most often the one between the scaphoid and lunate. These injuries can be missed on the first X-ray and over time disturb the alignment of the wrist bones. MRI or special X-ray views are used when suspected.
Frequently asked questions
My X-ray is normal but I still have pain. What should I do?
Scaphoid fractures may not show on the first X-ray. If suspicion remains, the wrist should be protected and assessed with MRI.
How long will I be in a cast?
It depends on the site of the fracture and how it heals. Scaphoid fractures may need a cast for longer than other wrist fractures.
When can I use my hand after screw fixation?
The hand can be used for light daily tasks soon after surgery. Heavy loads and sport are planned once imaging confirms healing.
Can a scaphoid non-union be treated years later?
Yes. Healing can be achieved with bone graft and a screw. If arthritis has developed, other surgical methods may be needed.
Why is the thumb included in the cast for a scaphoid fracture?
Thumb movements can also move the scaphoid, so the thumb is included in the cast to keep the fracture still.
The information on this page is general and does not replace an examination. An examination is needed to decide which treatment suits you.