When the breastbone is opened for heart surgery it is closed again with stainless steel wires, and those wires stay in permanently. Feeling them under the scar — usually as small hard bumps towards the top of the sternum — is normal and expected, and wires that can be felt but do not hurt are left alone. Wires are removed for a reason: pain that sits over a wire, a wire that has worked its way towards the skin, or a small opening over the scar that keeps discharging. Removal is not undertaken within the first three months, because the sternum is still healing and the wires are what hold it together. Dr Lawrence Okiror, Consultant Thoracic and Robotic Surgeon (GMC 6150382), assesses sternal wire problems at London Bridge Hospital and The Lister Hospital Chelsea within 2–3 days. Self-referrals welcome.
Last reviewed: September 2026 · Dr Lawrence Okiror FRCS(CTh) FRCSEd(CTh) · GMC 6150382
The wires are permanent. Small hard bumps under the scar, most often at the top of the breastbone, are the wires themselves. A wire you can feel but that does not hurt needs nothing done to it.
The wires hold the two halves of the sternum together while the bone knits. They are not removed inside the first three months. Discomfort in the early weeks usually settles as healing completes.
Where the symptomatic wires can be identified beforehand, only those are removed — and the published results are as good as removing all of them. Usually a day case.
Three quite different situations bring people to this page, and the answers are not the same. You can feel the wires but they do not hurt. This is much the commonest, and it is normal — the reassurance below is the whole answer. You can feel them and there is pain over them. This is the group in whom removal is considered, once the sternum has healed and other causes have been excluded. A wire is at the surface, or a small opening keeps discharging. That one needs assessing rather than watching.
The question that separates them is not how prominent the bump is and it is not how long ago the operation was. It is whether the wire is causing a problem. Being able to feel a wire is not a reason to remove it. Pain over a wire, a wire at the skin, or a sinus that will not close are reasons to remove it. Everything on this page follows from that distinction.
Both are common after heart surgery, and by feel alone they are not always easy to tell apart. Scar tissue is broader, softer and less sharply defined, and it usually softens over the first year. A wire is small, hard, and distinct — people describe it as a knot, a bead, or something with an edge to it — and unlike scar tissue it does not change with time. Wires are most often felt at the top of the breastbone, where there is least soft tissue over the bone, which is why so many people report a bump there and nothing lower down.
Examination settles the question in most cases, and where there is genuine doubt a plain chest X-ray shows every wire clearly. That is worth saying because people often expect a scan to be needed. It is not. The wires are metal and they are unmistakable on a simple film.
Becoming aware of the wires some time after the operation, rather than immediately, is also normal. The swelling of the first months settles, the tissues over the bone thin, and something that was always there becomes noticeable. Weight loss does the same thing — and for the same reason people become aware of collarbones and ribs. The wire has not moved; it has been uncovered. The same mechanism explains the lower breastbone becoming prominent after cardiac surgery, which is covered on the xiphoid process page.
This is the single most important thing on the page for anyone recently operated on. The breastbone is divided down the middle to reach the heart and is brought back together with wires. Those wires are not decoration — they are what holds the two halves in contact while the bone knits across the gap, in the same way a broken bone anywhere else needs to be held still to heal. Until that union is complete, the wires are load-bearing.
For that reason wires are not removed within the first three months after the original operation. Taking them out while the sternum is still healing risks the two halves separating, which is a far bigger problem than the one being treated. Soreness, tightness and an awareness of hardware over the scar during those early weeks and months are part of normal recovery, and in most people they settle as healing completes without anything being done at all.
In practice, most people who come to wire removal do so a good deal later than three months, once it is clear that the symptoms are not going to settle on their own. There is one exception to the waiting rule: a wire that is exposed through the skin, or an infected wire, is a different problem and is managed on its own timescale rather than by waiting.
Three situations, and they are not equally likely to be fixed by an operation. Being honest about that difference is the point of the consultation.
Pain that you can put a fingertip on, that is reproduced by pressing over that point, and that is provoked by the things that stretch the front of the chest — reaching overhead, arching backwards, yoga positions, press-ups and bodyweight work. This is the classic pattern, and it is the one for which the published outcome figures below apply.
Sometimes described as a wire poking out, or as something sharp that catches on clothing. The skin over it may be thinned, reddened, or broken. A wire that is no longer covered will not settle back down on its own, and this is the indication with the most reliable result from removal.
A pinhole or spot on the scar that weeps, crusts over, appears to heal and then breaks down again. This is a sinus tracking down to a wire, and it will keep recurring until the wire is dealt with. Repeated courses of antibiotics do not close it.
What is not on that list is a wire that can simply be felt. Nor is generalised aching across the whole front of the chest with no point that can be identified — that pattern is much less likely to be coming from the wires, and removal is correspondingly less likely to help. Where the pain is widespread rather than pinpoint, other chest wall causes are worth working through first, which is the subject of the unexplained chest pain page.
A breastbone that has not united. If the sternum clicks, grates, or feels as though it moves when you cough or push up out of a chair, the issue may be that the bone has not knitted rather than that a wire is irritating tissue. That is a different diagnosis with a different operation behind it, and removing the wires would make it worse, not better. It is the first thing to exclude in anyone whose pain has never settled since the original surgery.
Infection deep in the wound. A discharging sinus over a single wire is one thing. Infection involving the bone itself or the space behind it is another, and it is a serious problem that often needs a bigger operation, sometimes with plastic surgical input, rather than a wire being pulled out under sedation. It is more common in people with diabetes or poor circulation. Redness spreading across the scar, fever, or feeling generally unwell with it are the features that separate the two, and they warrant prompt medical attention rather than an outpatient appointment.
Both of these are excluded before wire removal is offered. That is the reason the assessment starts with the history of the original operation and an examination of how the sternum behaves, rather than with the bump itself.
It is a question people ask often, usually after noticing that they react to jewellery or belt buckles. Sternal wires are made of surgical stainless steel, which contains nickel — the commonest contact allergen there is. Reactions to sternal wires have been reported, with removal of the wires followed by resolution of the symptoms [3].
The honest position is that this evidence is thin. It consists of individual case reports rather than any series, and in the larger studies of wire removal the patients were not tested for metal allergy at all, so it is not possible to say how often allergy is genuinely the culprit. Nørgaard and colleagues did note that wire removal was carried out more often in patients with a history of allergy, which is suggestive rather than conclusive [1].
The practical answer is to test before operating, not after. Where allergy is genuinely suspected — a persistent eczematous rash over the scar, or a strong history of nickel reaction — patch testing through a dermatologist answers the question properly. Removing wires on the strength of an untested assumption means an operation without a diagnosis, and if the allergy was never the cause the symptoms will still be there afterwards.
The published experience is not large, but it is consistent, and it comes from surgeons reporting their own consecutive patients rather than from anything selected.
The figures used for consent are more conservative than the headline numbers. Nørgaard and colleagues suggested quoting patients with unexplained sternal pain a long-term rate of freedom from pain of about 65%, improvement with some remaining pain in 21%, no change in 14%, and worsening in 3% [1]. Those are the numbers worth holding in mind, because they describe the group with pain alone rather than a wire visibly at the surface.
For a wire protruding towards the skin, and for wire-related infection, the same series reported a higher success rate, although with smaller numbers behind it [1]. That matches what one would expect: removing a wire that has physically worked its way out solves an identifiable mechanical problem, whereas removing wires for diffuse pain is a judgement about where the pain is coming from.
The same study answers the question people ask most often about the scale of the operation. In 23 patients whose symptoms could be attributed to particular wires, only those wires were removed — and the results were as good as in patients who had all of them taken out [1]. There is no advantage in removing hardware that is not causing trouble.
It is a much smaller operation than the one that put the wires there. The work is done through the existing scar, so there is no new scar to speak of. The wires are exposed, untwisted and drawn out, and the skin is closed. It is usually a day case, performed under local anaesthesia with sedation or a light general anaesthetic, and most people go home the same day [4].
Wires can break as they are drawn out, particularly older ones and those twisted tightly at the original operation. That is an expected part of the procedure rather than a complication: the fragment is found and lifted out through the same incision. Very occasionally a fragment sits somewhere genuinely inaccessible and is causing no symptoms, in which case leaving it is reasonable, and that decision is made in theatre.
Recovery bears no resemblance to recovery from heart surgery. People are generally walking normally the same evening and back to ordinary activity within days, with the usual sensible caution about heavy lifting through the front of the chest while the skin heals. Where wires have been removed for a discharging sinus, the wound is managed slightly differently and that is explained at the time.
A thoracic surgeon. The sternum and the chest wall are thoracic territory, and sternal wire removal is a chest wall operation rather than a cardiac one. This matters in practice because people often assume they must go back to the cardiac surgeon who performed the original operation, and that is frequently difficult — the surgeon may be at another hospital, in another country, or no longer operating. You do not need to return to the original surgeon to have wires removed.
Wires from any median sternotomy behave the same way, whether the original operation was on the heart or in the chest. Sternotomy is also used for thoracic surgery — for a thymus gland operation, for some mediastinal tumours, and for operations on both lungs — and wire problems after those operations are managed identically.
Dr Okiror assesses sternal wire problems and chest wall pain at London Bridge Hospital and The Lister Hospital Chelsea, with outpatient consultations also available at the HCA clinics in Canary Wharf and the City of London. Private appointments are typically available within 2–3 working days. Self-referrals welcome. Bring the details of your original operation and any chest X-ray you have had since. Second opinions are available for patients already under another team’s care.
Questions most commonly asked by people who can feel the wires under their scar after heart surgery, or who have pain over them that has not settled.
Book an Assessment →Or call Jo Mitchelson:
020 7952 2882
Self-referrals welcome. Private appointments at London Bridge Hospital and The Lister Hospital Chelsea within 2–3 days. Dr Okiror examines the chest wall personally, establishes whether the wires are the source of the problem, and tells you clearly if they are not.
Jo Mitchelson, PA · 020 7952 2882 · pa@lungsurgeon.co.uk
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