A radial head fracture is the commonest fracture around the elbow. It usually happens after a fall onto an outstretched hand, and most are minor and heal well — but some need surgery, and a few come with important associated injuries. So how do we grade a radial head fracture, and how is each type managed?
What is the radial head?
The elbow is made up of three bones — the upper arm bone (humerus) and the two forearm bones (radius and ulna). The radial head is the disc-shaped top of the radius, which sits against the capitellum of the humerus and rotates as you turn your palm up and down. It’s also an important stabiliser of the elbow — which is why some radial head fractures matter beyond the break itself.
What causes a radial head fracture?
The classic mechanism is a fall onto an outstretched hand (FOOSH), which drives the radial head against the capitellum. It can also follow a direct blow to the elbow. Radial head fractures are common in sport and everyday falls, and are seen more often in younger, active people.
Symptoms of a radial head fracture
Typical features include:
- Pain on the outer side of the elbow, worse with movement
- Swelling and bruising around the elbow
- Difficulty and pain when turning the forearm (palm up and down)
- Tenderness over the radial head
- In some cases, a mechanical block to fully straightening or rotating the elbow, which is an important sign
How is a radial head fracture diagnosed?
An X-ray — with both front (AP) and side (lateral) views — is the first-line test and usually confirms the fracture. Sometimes the only clue on X-ray is a “sail sign” (a raised fat pad) indicating bleeding in the joint. A CT scan is used for complex or comminuted (multi-fragment) fractures, to define the pieces and plan surgery.
How are radial head fractures classified?
Radial head fractures are graded by the Mason classification, which guides treatment:
- Mason type 1 — non-displaced, or minimally displaced (less than 2 mm). Stable, with no mechanical block.
- Mason type 2 — displaced (more than 2 mm) or angulated (greater than 30 degrees), a partial fracture of the joint surface.
- Mason type 3 — comminuted (several fragments) and displaced, involving the whole radial head.
- Mason type 4 — any radial head fracture together with a dislocation of the elbow (a modification of the original classification).
Radial head fracture treatment
Treatment follows the grade:
Mason type 1 (non-displaced)
Treated without surgery. A short period in a sling (usually less than a week) for comfort, followed by early movement — because moving the elbow early is the key to avoiding stiffness, which is the main complication. Most do very well.
Mason type 2 (displaced)
Some are managed non-operatively with early movement, particularly if there’s no mechanical block. Where there’s a block to rotation, or significant displacement, surgery to fix the fragment (open reduction and internal fixation, ORIF) restores the joint surface.
Mason types 3 and 4 (comminuted / with dislocation)
Usually need surgery. Options are fixing the fragments (ORIF) or, where the radial head is too shattered to reconstruct, replacing it (radial head replacement). A type 4 fracture with an elbow dislocation also requires addressing the associated ligament injuries to restore stability.
Don’t-miss associated injuries
A radial head fracture isn’t always an isolated injury, and the associated ones matter. Because the radial head stabilises the elbow and forearm, a fracture can come with an elbow dislocation, a tear of the forearm’s interosseous membrane (an Essex-Lopresti injury, which also involves the wrist), or the “terrible triad” of the elbow. This is why the wrist and the whole forearm are assessed, not just the elbow, and why a careful specialist review matters.
The terrible triad consists of posterior dislocation of the elbow, fracture of the radial head, and fracture of the coronoid process. Any evidence of a radial fracture with a coronoid fracture suggests the elbow joint may be unstable and warrants further imaging, such as MRI and CT.
Frequently asked questions about a radial head fracture treatment
How long does a radial head fracture take to heal?
A non-displaced (Mason type 1) fracture usually settles over about 6 weeks, with early movement started within days to avoid stiffness. Displaced or surgically treated fractures take longer to heal, with a graded return to activity over a few months. Stiffness — not non-union — is the main issue to prevent.
Do I need surgery?
Most non-displaced fractures (type 1) don’t — they heal well with early movement. Displaced fractures with a mechanical block, and comminuted or dislocated fractures (types 2–4), often do need surgery, either to fix or replace the radial head. The Mason grade guides the decision.
Why is early movement so important?
Because the main complication of a radial head fracture is elbow stiffness, not failure to heal. Moving the elbow early — once it’s safe to do so — keeps the joint supple and gives the best functional result. This is why even a broken elbow is often mobilised early rather than kept still.
Can this fracture cause long-term problems?
Most heal well. Some stiffness can persist, and fractures involving the joint surface carry a small risk of arthritis years later. Associated injuries (such as a dislocation, an Essex-Lopresti injury or co-existing coronoid fracture), if missed, are the bigger cause of long-term trouble — which is why a thorough assessment matters.
Final word from Sport Doctor London about a radial head fracture
A radial head fracture is the commonest elbow fracture, usually from a fall on an outstretched hand. The Mason grade guides treatment — most minor (type 1) fractures respond well to early movement, while displaced, comminuted, or dislocated fractures often require surgery. The keys are grading it correctly, mobilising early to avoid stiffness, and not missing the associated injuries.
If you have elbow pain after a fall, Dr Masci can assess you in London, including the right imaging. Contact the team here or call +44 (0) 203 488 0350.
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