What a broken arm is
The upper arm bone (the humerus) runs from the shoulder to the elbow. Below the elbow, two bones run to the wrist: the radius on the thumb side and the ulna on the little-finger side, and the radius turns around the ulna to turn your palm up and down. This guide covers breaks of the middle parts (the shafts) of these bones.
A break can be a crack or in several pieces, still lined up or out of place, and open, with a wound over it, which needs urgent treatment because of the risk of infection. Two forearm injuries combine a break with a dislocation: a Monteggia injury (the ulna broken and the top of the radius out of joint at the elbow) and a Galeazzi injury (the radius broken and the ulna out of joint at the wrist). Breaks at the top of the humerus, at the elbow and at the wrist end of the forearm have their own guides.
Sources 1, 2
Who breaks the middle of the armEmerging evidence
Breaks of the upper arm shaft are 1% to 3% of adult fractures. In Denmark, 23,718 were recorded over 23 years: about 25 for every 100,000 adults each year, 62% in women, 78% in people aged 50 or over, and 87% treated without surgery. In 936 breaks at one Finnish trauma centre, over 60% followed a simple fall, the commonest groups were older women and young men, 24% of people had another injury (most often to the radial nerve, in 10%), 3% of breaks were open, and 9.2% of people had died within a year, a sign of how frail many of them were.
In adults it takes a strong force to break the middle of the forearm, so both bones usually break: from a fall onto an outstretched arm in sport or from a height, or in a road crash. A single ulna usually breaks from a direct blow, such as an arm raised to protect yourself.
In children, forearm breaks are up to half of all fractures, mostly from falls in the playground or in sport, but 3 in 4 are at the wrist end, which our broken wrist guide covers. Children's bones are softer, so they often bend and crack on one side (a greenstick fracture) or buckle.
Sources 3, 4, 5, 1, 2
How it's recognised
The NHS says a broken arm is usually painful, swollen, bruised and difficult to move, and it may change colour, look bent or twisted, or feel numb. A broken forearm often looks bent and shorter, and you can't turn your palm up or down. You'll probably need an X-ray.
In hospital the team checks the skin, the pulse, the feeling and movement in the fingers, and the joints above and below the break, with X-rays of the elbow and wrist in children, because one fall can break more than one place. UK orthopaedic standards ask for the pulse, the blood supply to the fingers and each nerve to be checked and written down when you arrive, and again after the bones are set or a cast is put on.
Sources 6, 1, 2, 7, 8
The radial nerve and wrist drop
The radial nerve winds around the back of the upper arm bone on its way to the hand. If a break bruises or stretches it, the back of the hand can feel numb and the muscles that lift the wrist and fingers weaken, so you can't pick things up or carry them in that hand. The drooping wrist is called wrist drop.
It happens with about 1 in 10 breaks of the upper arm shaft: 10% in a review of 1,758 people and in the Finnish series, and 11.8% in an older review of 4,517 breaks. It's commoner with breaks in the middle and lower part of the shaft, and with breaks straight across or in a spiral. A new palsy after an operation is commoner than after bracing: 4% against 0.4% in one review, and 17.4% against 0.7% in pooled trials. In children with this break it's rare, at about 4%.
How often it recovers, and whether the nerve should be looked at in an operation, are covered in the evidence notes below: the figures and the advice differ.
Sources 9, 10, 11, 5, 12, 13
What the X-ray does and doesn't mean
A healed upper arm bone often keeps a slight bend on the X-ray, and that's usually fine. An Edinburgh NHS sheet says the humerus has a great ability to heal and does not need to be in a perfect position, and in a large US series of braced breaks, 87% of those X-rayed healed with less than 16 degrees of sideways bend, which the authors judged acceptable for use and appearance. Children's bones reshape as they grow, so a child's forearm can be accepted with more angle than an adult's.
What matters more than the picture is whether the bone joins. Pain in the arm that is still there beyond about 3 months, difficulty lifting anything heavy, and a clicking at the break can mean it hasn't, and need a review.
Sources 14, 15, 7
How it usually goesEmerging evidence
Upper arm, in a brace: the brace goes from the shoulder to the elbow and is worn day and night with a collar and cuff sling until the clinic says, usually 6 to 8 weeks for a simple break and sometimes up to 20. NHS leaflets say the bone takes 9 to 12 weeks to join, or 12 to 26. Physiotherapy often starts 6 to 12 weeks after the injury, and simple daily activities can take up to 4 months, longer with strenuous work. In a US trial of 58 people, a plaster splint for the first days was a little less painful than a brace straight away; an older US series used a splint for an average of 9 days first. UK practice varies.
In the Finnish FISH trial, two-thirds of the people treated in a brace healed and at 2 years scored as well on an arm disability questionnaire as those operated on straight away (6.0 and 6.8 out of 100, where 0 means no disability). The third whose bone didn't heal and needed a later operation scored 17.5.
Stiffness is the usual problem afterwards: the NHS says the arm may be stiff and weak for several months once the cast or brace is off. When the braces came off in the large US series, 98% of people had lost no more than 25 degrees of shoulder movement.
Forearm, adults: the bones take 3 to 6 months to heal fully, and some stiffness is common but doesn't usually affect daily life. Plates usually stay in. In 30 adults 5.4 years after plating both bones, the injured arm had 63% to 84% of the other side's strength; 21 years on, in 71 people, forearm turning was 91% and grip 94% of the other side, and 72% had no pain.
Sources 16, 17, 18, 19, 15, 20, 6, 1, 21, 22
Children's forearm breaks: how they healEmerging evidence
A greenstick break heals in about 3 to 6 weeks, and a break that had to be set over about 6 weeks. A stable buckle break needs 3 to 4 weeks in a cast or splint, and a Monteggia injury 6 to 10 weeks. After the cast, the wrist and elbow are often stiff for 2 to 3 weeks and loosen up without physiotherapy, and most children have their movement back within 2 to 4 weeks.
Children do well in the long run: 11 years after casting, 47 Finnish children had normal forearm turning and grip. Breaks through a growth plate may be followed for up to a year. Forearm shaft breaks can happen again: in 2% to 8% in earlier studies, and in 7% within a year in a Danish group of 837 children.
Sources 23, 24, 2, 25, 26, 27
Older adults: bones and falls
Most upper arm breaks in later life follow a simple fall. NICE (the National Institute for Health and Care Excellence) asks for a fracture risk assessment for people aged 50 or over who break a bone in a fall from standing height or less, and a falls assessment for people who have fallen. The NHS says a fracture liaison service can help if you're over 50. Weak bones don't slow healing, the Royal Osteoporosis Society says, and NICE advises against anti-inflammatory painkillers for frail or older people with fractures.
Sources 5, 28, 29, 6, 30, 31
