Carpal Fractures
Breaks in the small bones of the wrist
Quick Facts
- Type: Bone fracture (wrist)
- Most common: Scaphoid fracture
- Common cause: Fall onto an outstretched hand
- Concern: Easy to miss; some heal slowly
Overview
The wrist contains eight small bones called the carpal bones, arranged in two rows between the forearm and the hand. A carpal fracture is a break in one of these bones. They are usually caused by a fall onto an outstretched hand, a direct blow, or a high-energy injury.
By far the most commonly fractured carpal bone is the scaphoid, on the thumb side of the wrist. Scaphoid fractures are important because they can be easy to miss on early X-rays and because part of the bone has a limited blood supply, which means some fractures heal slowly or fail to heal without proper treatment. Other carpal bones, such as the triquetrum or lunate, can also break. Prompt diagnosis and appropriate immobilization or surgery give the best chance of full healing and a return to normal hand function.
Symptoms
Carpal fractures can cause symptoms that are surprisingly mild, which is one reason they are sometimes overlooked:
- Pain and tenderness in the wrist, often on the thumb side for scaphoid fractures
- Swelling around the wrist
- Pain with gripping, pinching, or moving the wrist
- Tenderness in the small hollow at the base of the thumb (the anatomical snuffbox)
- Reduced grip strength
- Bruising, which may be subtle
Because pain may be modest, some people assume they only have a sprain and delay care. Persistent wrist pain after a fall, especially tenderness at the base of the thumb, should be evaluated, as an untreated scaphoid fracture can lead to long-term problems.
Causes
Carpal fractures result from force transmitted through the wrist:
- Falls onto an outstretched hand: The most common cause, driving force into the carpal bones, especially the scaphoid.
- Direct blows: Impact to the wrist from sports, tools, or accidents.
- High-energy trauma: Car crashes and falls from height can fracture and dislocate carpal bones.
- Repetitive stress: Less commonly, repeated loading can contribute to stress fractures in athletes.
Risk Factors
- Participation in sports with falls, such as skateboarding, cycling, and contact sports
- Younger, active adults (scaphoid fractures are common in this group)
- Osteoporosis or low bone density in older adults
- Activities involving repetitive wrist loading
- Smoking, which impairs healing of the scaphoid in particular
- A prior wrist injury
Diagnosis
Diagnosing carpal fractures, especially of the scaphoid, can require more than a single X-ray:
- Physical exam: Checking for tenderness, swelling, and specifically pain in the anatomical snuffbox at the base of the thumb.
- X-rays: The first test, though some scaphoid fractures are invisible at first and only become apparent days later.
- Repeat imaging: If a fracture is suspected but not seen, the wrist is often immobilized and re-examined or re-imaged in one to two weeks.
- MRI or CT: More sensitive scans used to confirm a suspected fracture early or to assess complex injuries.
Treatment
Treatment depends on which bone is broken, the location and displacement of the fracture, and how long ago it occurred:
- Casting: Non-displaced fractures, including many scaphoid fractures, are immobilized in a cast, sometimes for several weeks to a few months because of the slow healing of certain bones.
- Surgery: Displaced fractures, certain scaphoid fractures, and fractures that fail to heal often need surgery with a screw or pins to stabilize the bone.
- Bone grafting: Used when a scaphoid fracture has not healed or has poor blood supply.
- Pain control and rehabilitation: Pain relief early on, followed by therapy to restore motion and strength once healing allows.
Following the immobilization plan closely and avoiding smoking improve the odds of healing, particularly for the scaphoid, where incomplete healing can lead to arthritis over time.
Prevention
Carpal fractures cannot always be avoided, but the following help:
- Wear wrist guards for skating, skiing, and snowboarding
- Keep bones strong with calcium, vitamin D, and weight-bearing exercise
- Improve balance and strength to reduce falls
- Get prompt evaluation of wrist pain after a fall rather than assuming it is only a sprain
- Avoid smoking, which slows fracture healing
When to See a Doctor
See a doctor for wrist pain that persists after a fall or injury, particularly tenderness at the base of the thumb, even if you can still move the wrist and assume it is just a sprain. Early diagnosis is especially important for scaphoid fractures, which can heal poorly if missed.
Seek prompt or emergency care if the wrist is visibly deformed, if there is an open wound with exposed bone, if swelling is severe, or if the hand or fingers become numb, tingly, pale, or cold, which may signal pressure on nerves or blood vessels.
Frequently Asked Questions
Which carpal bone breaks most often?
The scaphoid, on the thumb side of the wrist, is by far the most commonly fractured carpal bone. It typically breaks after a fall onto an outstretched hand and can be easy to miss on early X-rays.
Why are scaphoid fractures a special concern?
Part of the scaphoid has a limited blood supply, so some fractures heal slowly or fail to heal if not treated properly. A missed scaphoid fracture can lead to long-term wrist problems and arthritis, which is why persistent wrist pain after a fall should be checked.
Can a carpal fracture be mistaken for a sprain?
Yes. Carpal fractures, especially of the scaphoid, often cause only mild pain and swelling, so people may think they have a sprain and delay care. If wrist pain continues after a fall, it should be evaluated to rule out a fracture.
How long does a carpal fracture take to heal?
It varies by bone and fracture. Many scaphoid fractures need a cast for several weeks to a few months because of slow healing, while some other carpal bones heal faster. Surgery may shorten immobilization or be needed if the bone does not heal.
Do all carpal fractures need surgery?
No. Non-displaced fractures are often treated with a cast. Surgery is used for displaced fractures, certain scaphoid fractures, and fractures that fail to heal, typically using a small screw or pins.
References
- American Academy of Orthopaedic Surgeons (OrthoInfo). Scaphoid Fracture of the Wrist.
- Mayo Clinic. Broken wrist — Symptoms and causes.
- American Society for Surgery of the Hand. Wrist fractures.
- MedlinePlus, U.S. National Library of Medicine. Wrist injuries and disorders.