What is a boxer's fracture?

A boxer's fracture is a break in the neck of the fifth metacarpal, the long bone in the hand that connects the wrist to the base of the little finger. The bone usually breaks just behind the knuckle, with the knuckle (the head of the bone) tipping downwards into the palm. Despite the name, it is rarely seen in experienced boxers, who learn to punch correctly, it is far more common in the inexperienced, often following an angry punch at a wall.

The injury usually looks dramatic: the knuckle appears flattened or absent, the hand is swollen and bruised, and a small lump may be visible in the palm where the bone end has dropped. Despite this appearance, most boxer's fractures heal extremely well without surgery. A degree of "angulation" (tipping down) of the knuckle is well tolerated, the bone has remarkable capacity to remodel, and the small functional cost (slight loss of grip strength) is usually clinically insignificant.

The key things to check are: how much the bone is tipped (the angulation), whether the finger rotates correctly when bent (malrotation is much less acceptable), and whether the skin over the knuckle is broken (a "fight bite" wound, which can become infected if it has cut through into the joint after striking a tooth).

Common causes

Closed-fist punch, the dominant cause
Direct blow to the back of the hand
Fall onto a clenched fist
Sports injury (rarely; usually inexperienced contact)

Who is at risk? Young men in their teens and twenties are by far the most affected group. Alcohol intoxication is associated with around half of all cases. Recurrent injuries should prompt enquiry about anger management or interpersonal violence.

Symptoms

Symptoms vary depending on the severity and duration of the condition. Common symptoms include:

Pain and swelling over the knuckle of the little finger after a punch
Loss of the normal prominence of the knuckle
A small lump visible in the palm
Bruising and stiffness of the little and ring fingers
Pain on making a fist
Skin laceration over the knuckle, suggests a "fight bite" wound (urgent)

When to seek help: See your GP or attend an Emergency Department for X-ray. Any laceration over the knuckle should be treated as a "fight bite" wound and assessed urgently, these can cause serious joint infections if not washed out promptly.

How is it diagnosed?

Your hand surgeon will take a detailed history and examine the hand and wrist. The following investigations may be arranged to confirm the diagnosis:

Plain X-rays of the hand in three views (PA, oblique, lateral)
Measurement of the angulation of the metacarpal neck
Assessment for malrotation (the most important clinical sign)
Examination of the skin for fight bite wounds
Assessment of finger movement, including the cascade of the fingers when curled

The single most important assessment is for malrotation. When the fingers are flexed into a fist, they should all point towards the scaphoid tubercle, if one finger crosses over (scissors with) the others, malrotation is present and surgery is needed. Angulation up to 30-40 degrees is usually well tolerated in this bone.

Treatment pathway

Treatment is tailored to the severity of the condition, your age, activity level, and overall health. Most conditions are treated in a stepwise fashion, starting with the least invasive options.

First line, most cases

Buddy strapping or soft splint

For fractures with acceptable angulation and no malrotation, treatment is straightforward: a buddy strap to the ring finger and early movement, sometimes with a short period (1-2 weeks) in a cast for pain relief only. Most fractures heal in 4-6 weeks with minimal long-term issues.

Closed reduction

Manipulation under anaesthetic

For fractures with significant angulation (typically >30-40 degrees), the bone is reduced under local or regional block. The classic technique (Jahss manoeuvre) bends the metacarpophalangeal joint to 90 degrees and pushes the knuckle upwards. A cast or splint holds the position for 3-4 weeks. Many fractures slip back after manipulation.

Surgical option

K-wire or plate fixation

For malrotated, severely angulated, multiple, or open fractures, surgical fixation is offered, either with crossed K-wires (most common) or a small plate. Allows earlier movement. Open fight-bite wounds need formal washout in theatre before any fixation.

Recovery

Most boxer's fractures heal well within 6 weeks. Some swelling and stiffness in the knuckle is common for several weeks. The flattened knuckle profile is permanent in most cases but rarely causes any functional issue. Hand therapy is rarely required.

Buddy strap and movement: 4-6 weeks
Cast (if used): 2-3 weeks
Return to light activities: 4-6 weeks
Heavy gripping and sport: 8-12 weeks

What results can I expect?

Excellent in the great majority of cases. Patients should be warned that the knuckle may always look slightly flattened compared to the other side, but that this does not affect strength or function. Outcomes after surgery are equally good but should be reserved for the small group with rotational deformity or open wounds.

In numbers

5th

metacarpal most often[1]

the bone behind the little finger

Punching

is the usual mechanism[1]

often a closed-fist punch onto a hard surface

Most

treated without surgery[1]

closed reduction and protective splinting suffice for most cases

4-6

weeks immobilised[1]

typical splinting or buddy strapping period

What the evidence shows

A degree of angulation is well tolerated in the 5th metacarpal because of the mobility of the carpometacarpal joint behind it, much more than in the index or middle metacarpals[1]

Rotational deformity (scissoring of the fingers on making a fist) is the key indication for surgery and must be carefully assessed at presentation[1]

A "fight bite" injury (a punch that breaks the skin over a knuckle by contact with teeth) is a surgical emergency because of the risk of joint sepsis[1]

Hand therapy with early controlled movement reduces stiffness and accelerates return to function[2]

A small bump on the back of the hand often remains as a cosmetic feature, but does not affect function[1]

When can I…?

Typical activity timelines for this condition. These are approximate and vary considerably between patients. Always follow the specific guidance given by your surgeon and hand therapist.

Activity	Typical timeline	Notes
Move fingers	Day one	Active finger movement from day one (including in the splint where possible) prevents stiffness.[2]
Drive	When grip is safe	When the splint allows safe grip, often 2-4 weeks. Confirm with surgeon and insurer.[3]
Shower	Splint covered	A waterproof cover keeps the splint dry.
Desk work	Within a few days	Light typing and writing with the splint or buddy strap in place.[1]
Manual work	4-6 weeks	Heavy gripping and impact wait until the bone has healed and tenderness has settled.[1]
Sport	6-8 weeks	Non-contact sport earlier, contact and impact sport (and any sport involving punching) only after full healing.
Make a full fist	Within weeks	Most patients regain a full fist within 4-6 weeks with hand therapy. Persistent inability is uncommon and worth reviewing.[2]

Is this normal?

Common concerns from patients with this condition or recovering from treatment, and whether they are expected or worth mentioning to your team.

Yes. A small permanent bump (loss of the prominence of the knuckle and a hump just behind it) is common after a fifth metacarpal neck fracture. It is cosmetic and does not affect function.[1]

Yes. Some loss of knuckle prominence on a clenched fist is common because the bone heals slightly bent. Function is usually unaffected.[1]

No, this is a sign of rotational malunion and requires assessment. Rotational deformity is one of the few reasons a metacarpal fracture needs surgery. Contact your team.[1]

Mild tenderness over the fracture site and the joint surface can persist for months after healing, particularly with cold or heavy gripping. It usually settles in the first year.[1]

No, this needs urgent assessment. Any break in the skin over a knuckle from a punch (a "fight bite") is at high risk of joint infection. Even a small wound needs prompt attention, often surgical washout and antibiotics.[1]

References & further reading

References are to UK clinical guidance and patient information from recognised organisations. This page is for general information and does not replace personalised advice from your own clinical team.

Boxer's fracture