Broken leg

Legs break in very different ways: hit by a car at a crossing, landing badly on a trampoline, falling down stairs, or simply running on hard roads for weeks without a rest day. Some fractures are obvious at once, because the leg bends where there is no joint. Others are mistaken for a sprain for a week and a half. What follows is how to tell one from the other, what to do in the first hours, and why in a shin fracture the pain building up under the cast can matter more than the bone itself.

Which bones break, and why

The leg runs from the pelvis to the toes, and fractures behave quite differently depending on the level.

• Thigh bone. The largest bone in the body. In a young adult it breaks only under real force — a collision, a fall from height — and is always treated in hospital. In an older person it is the upper end near the joint that goes, and a fall from standing height is enough.
• Shin. Two bones: the thick tibia and the slim fibula. They break when the foot twists, from a direct blow, or on the ski slope. The tibia lies straight under the skin, which is why its fractures are more often open ones.
• Ankle. The commonest of all: a foot rolls off a kerb and something cracks. Telling an ankle fracture from a bad sprain by eye is not possible.
• Foot and toes. Something heavy dropped, a little toe against furniture, a missed step on the stairs. The small bones across the midfoot often break without anyone noticing.

Bone gives way more easily when it is weakened: after the menopause, on long-term steroid treatment, or with vitamin D deficiency. Separate again is a fracture in an adult with no convincing injury: if a bone cracks during an ordinary step, the cause is looked for inside the bone, secondary cancer deposits included.

How to tell it is a fracture

Reliable signs:

• the leg is bent, twisted or visibly shorter than the other one;
• bone is visible in a wound;
• moving the leg produces a grating you can hear or feel;
• bearing any weight at all is impossible.

Less reliable but common signs: swelling that grows quickly, bruising that spreads down to the toes or under the ankle bone, and sharp pain when you press on the bone itself rather than on soft tissue.

The trouble is that an undisplaced crack looks exactly like a sprained ligament: it hurts, it swells, weight-bearing is unpleasant but possible. Hence a simple rule — if you cannot take four steps after the injury, if the pain is pinpoint and sits directly over bone, or if there is no improvement after two or three days, you need an X-ray. Waiting it out achieves nothing here.

Stress fracture: pain with no injury

This is a story of its own, and almost always missed. A bone can crack not from a single impact but from many small loads, when it is not given time to repair itself. The typical account: someone suddenly raises their weekly mileage or changes surface, and a few weeks later the shin or the foot starts to hurt — at first at the end of a run, then from the start, then when simply walking.

What to look out for:

• the pain sits in one spot you can point to with a finger;
• it settles overnight and comes back with load;
• a plain X-ray often shows nothing for the first two or three weeks, which does not mean the bone is intact — when the picture is convincing, an MRI is the answer;
• in female runners with irregular or absent periods and tight food restriction these fractures come easily, because the body simply has no spare resource for bone repair.

Many stress fractures are harmless and heal with rest. But those in the neck of the thigh bone and along the front edge of the tibia are dangerous — they can go on to a complete break. So groin pain in a runner, or a stubborn ache along the shin bone, is not something to push through for another week.

Call an ambulance right now if

• the leg is deformed, twisted or shortened;
• bone is showing through a wound, or the wound is deep and dirty;
• bleeding does not stop with pressure;
• the foot has turned pale, cold or numb and the toes will not move;
• cold sweat, weakness, a fast pulse, shallow breathing or greying skin and lips appear — a fractured thigh or shin can bleed heavily inside.

While you wait, do not move or straighten the leg and do not let any weight go through it. Pack rolled clothing or a blanket along both sides so it cannot flop over. Cover an open wound with a clean cloth and press if it bleeds. Do not give food or drink, since surgery may follow. Painkillers from the cupboard are acceptable if the person is fully awake and certainly not heading to theatre within the hour, but waiting for the medical team is better. Across Europe the emergency number is 112; elsewhere, use your local one.

There is one more situation that sends you back to hospital after the cast is already on. If the pain does not settle but grows hour by hour, if it is out of proportion to the injury, if it worsens when you try to straighten the toes, if the shin feels bursting from within, the skin is tight and numbness appears, the muscles may be being squeezed inside their closed compartment. The clock runs in hours: the cast has to be split and sometimes surgery is needed. It is a rare complication, but it is exactly the one nobody mentions and the one that costs people their leg.

How it is treated

The aim is single: put the fragments back where they belong and hold them there while they knit. The method depends on the bone and on the displacement.

• A cast or a rigid brace when the fragments are already in line. Ankle, foot and undisplaced shin fractures are usually managed this way.
• Surgery. A nail is passed inside the bone, or a plate and screws are applied on the outside. The thigh bone and displaced shin fractures are almost always operated on, because it gets the person upright sooner.
• External frame. Pins passed through the skin into the bone with a structure outside. Used for severe open fractures and heavy swelling, often as a temporary measure.
• An open fracture is always urgent: the wound is washed out in theatre within hours and antibiotics are started immediately, otherwise infection settles into the bone and stays for years.

Traction with weights and pulleys, standard treatment for decades, is now used rarely and mostly as a temporary step. When weight-bearing may start is agreed separately: the operating surgeon decides that, and improvising is expensive here.

Recovery

A shin bone usually knits in six weeks to three months, the thigh bone takes longer and the small bones of the foot less; getting strength and a confident stride back takes several months more. Follow-up X-rays show whether healing is on track.

What helps and what gets in the way:

• move your toes and work the joints that are free from the first days — it shifts the swelling;
• keep the cast dry and never push anything under it to scratch, because grazed skin under a dressing gets infected;
• once the cast is off the leg will look thin and feel stiff; that is normal and it is treated with exercise, not with rest;
• smoking measurably slows bone healing, and it is one of the few things entirely within your control;
• go back to contact sport and running when your doctor says so, not when the pain stops.

While the leg is immobilised, blood pools in the veins. If the calf of the healthy leg becomes firm, hot and painful, or sudden breathlessness and chest pain on breathing in appear, that is a clot and its complication, and it needs emergency care rather than observation.

Online consultation

A fresh fracture is diagnosed on an X-ray and treated with hands, so a suspected one means a trip to the emergency department. Everything afterwards, though, is convenient to discuss from home: going through the radiology report, understanding whether healing is progressing, working out why the leg still swells in the evening a month after the cast came off, and when driving or the gym become reasonable again. A separate reason to get in touch is recurring pain with no injury in someone who runs: the doctor can advise which scan makes sense and which specialist to see.

This material is for information only and does not replace medical advice.