Ulnar Fracture

Overview

An ulnar fracture is a break in the ulna, the forearm bone that runs along the little-finger side of the arm, opposite the radius. The ulna helps form both the elbow and the wrist joints and is essential for forearm rotation and stability. Fractures can occur anywhere along its length, from the bony tip of the elbow (the olecranon) to the wrist.

A classic pattern is the so-called nightstick fracture of the middle of the ulna, which happens when a person raises an arm to shield the head from a blow. The ulna may break on its own or together with the radius, and some ulna fractures occur alongside a dislocation of a nearby joint, which changes treatment. Most ulnar fractures heal well, although the right treatment, from casting to surgery, depends on the location, alignment, and whether other injuries are present.

Symptoms

Symptoms depend on where the ulna is broken but usually appear right after the injury:

• Pain along the forearm, elbow, or wrist
• Swelling and tenderness over the break
• Bruising
• Difficulty bending or straightening the elbow or rotating the forearm
• A visible deformity if the bone is displaced
• Reduced grip strength
• Numbness or tingling in the hand if a nerve is affected

An open wound over the fracture, an obvious deformity, severe swelling, or numbness and coldness of the hand are warning signs of a serious injury that needs immediate care.

Causes

The ulna breaks when a force is greater than the bone can withstand:

• Direct blows: A strike to the forearm, including raising the arm to protect the head, can break the middle of the ulna.
• Falls: Landing on the arm or elbow can fracture the ulna, sometimes along with the radius.
• High-energy trauma: Car crashes and sports collisions can cause forearm fractures, occasionally with joint dislocations.
• Weak bones: Osteoporosis allows fractures from relatively minor falls.

Risk Factors

• Contact sports and activities with a high fall risk
• Osteoporosis or low bone density
• Older age and conditions that affect balance
• Physical assault (raising the arm to block a blow)
• High-speed activities such as cycling and motorcycling
• Smoking and poor nutrition, which weaken bone

Diagnosis

Diagnosis relies on examination and imaging to define the fracture and check for associated injuries:

• Physical exam: Assessing pain, swelling, deformity, elbow and wrist motion, and the nerves and circulation of the hand.
• X-rays: The main test, showing the location and alignment of the break. Views of the elbow and wrist are important because an ulna fracture can be paired with a joint dislocation.
• CT scan: Used for complex fractures, particularly those at the elbow or involving a joint surface.

Treatment

Treatment is tailored to the location of the fracture, its alignment, and any related injuries:

• Casting or splinting: Stable, well-aligned isolated ulna fractures, such as some nightstick fractures, can heal in a cast or functional brace.
• Surgery: Displaced fractures, fractures involving both forearm bones, those at the elbow tip, or those with a joint dislocation usually need surgery with plates and screws to restore alignment and allow early motion.
• Pain control: Rest, ice, elevation, and pain relievers help in the first days.
• Rehabilitation: Once healing is underway, exercises and therapy restore elbow and wrist motion, forearm rotation, and strength.

Restoring the precise alignment of the forearm bones matters because they work together to allow the hand to turn palm up and palm down. Healing typically takes several weeks, with strength and motion improving over months.

Prevention

Steps to reduce the risk and severity of ulnar fractures include:

• Keep bones strong with calcium, vitamin D, and weight-bearing exercise
• Get evaluated and treated for osteoporosis if at risk
• Wear protective gear for cycling, skating, and contact sports
• Reduce fall hazards at home and improve balance with exercise
• Avoid smoking, which impairs bone strength and healing

When to See a Doctor

See a doctor promptly after a forearm or elbow injury with significant pain, swelling, bruising, or difficulty moving the arm, even if you can still use it, because fractures and accompanying joint injuries are not always obvious.

Seek emergency care right away if the forearm is visibly deformed, if bone protrudes through the skin, if swelling is severe, or if the hand or fingers become numb, tingly, pale, or cold. These can indicate a serious fracture or injury to nerves or blood vessels that needs urgent treatment.

Related Topics

Frequently Asked Questions

References

1. American Academy of Orthopaedic Surgeons (OrthoInfo). Adult Forearm Fractures.
2. Mayo Clinic. Broken arm — Symptoms and causes.
3. National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS). Sports Injuries.
4. MedlinePlus, U.S. National Library of Medicine. Arm injuries and disorders.