Informed Consent After Montgomery: How Standards Differ Worldwide

The most consequential change in surgical medico-legal practice in the last thirty years was not a new operation or a new device. It was the collapse of the idea that surgeons decide how much surgeons should tell patients.

For most of the twentieth century, the adequacy of disclosure was judged the same way as the adequacy of an operation: by asking whether a responsible body of practitioners would have done the same. That is no longer the law in most of the common-law world. The standard is now set by reference to what a patient would want to know — and a surgeon who quotes departmental custom as a defence for what they did not mention is quoting something the court is no longer interested in.

This post sets out the current test, compares how jurisdictions arrived at it, and translates it into what a defensible consent conversation actually looks like in an orthopaedic clinic. For the communication craft of the conversation itself, see Doing Consent Well; this post is about the legal standard behind it.

What changed, and when

Australia, 1992

Australia got there first. In Rogers v Whitaker, Maree Whitaker underwent surgery on a right eye that had been blind since childhood. The operation was performed competently, but she developed sympathetic ophthalmia in her previously good left eye and was left effectively blind. The risk was roughly 1 in 14,000. She had not been warned of it — though she had asked repeatedly and specifically about complications affecting her good eye.

The High Court of Australia held that the duty to warn is not governed by professional opinion. A doctor must disclose any material risk, and a risk is material if a reasonable person in the patient's position would attach significance to it, or if this particular doctor is or should be aware that this particular patient would attach significance to it.

The second limb is the one that decided the case. A 1-in-14,000 risk is small by any measure. To a woman who had asked directly about her only seeing eye, it was everything.

The United Kingdom, 2015

The UK took another 23 years. In Montgomery v Lanarkshire Health Board [2015] UKSC 11, Nadine Montgomery was a woman of small stature with diabetes. Diabetic mothers carry a 9–10% risk of shoulder dystocia in vaginal delivery. She was not told. Her obstetrician's reasoning was that the risk of a serious outcome was very small and that, if told, mothers would opt for caesarean section, which she did not consider to be in their interest. Shoulder dystocia occurred and the baby was born with severe disabilities.

The Supreme Court overruled Sidaway and adopted essentially the Australian test: the doctor must take reasonable care to ensure the patient is aware of any material risks in the recommended treatment, and of any reasonable alternative or variant treatments.

Two features of the reasoning matter more than the headline.

First, the Court rejected the paternalism explicitly. The obstetrician's honest belief that disclosure would lead patients to make what she considered the wrong choice was precisely the attitude the judgment dismantled. A patient is entitled to make a decision the surgeon considers unwise.

Second, the Court was clear that materiality is not a function of magnitude alone. It depends on the nature of the risk, its effect on this patient's life, the importance to this patient of the benefit being sought, and the alternatives available and their risks.

The test, stated plainly

A risk is material if either limb is satisfied:

1. The objective limb — a reasonable person in the patient's position would be likely to attach significance to it; or
2. The subjective limb — the surgeon is, or should reasonably be, aware that this patient would be likely to attach significance to it.

The subjective limb is where most real cases are won and lost, and it is the limb surgeons under-serve. It is triggered by what you know about the patient — which means it is triggered by what you asked them. A surgeon who never asks what the patient does, or what they are hoping to get back to, cannot be aware of what would matter to them, and that ignorance is not a defence when the information was there for the asking.

What "material" means in an orthopaedic clinic

Abstract tests become concrete quickly in orthopaedics, because so many of our operations trade one function for another.

That last row is the most commonly litigated shape of failure, and it is not a failure to quote a complication. It is a failure to present a genuine alternative. See our topic on distal radius fractures in older adults for the underlying evidence.

Doing nothing is always one of the alternatives, and it is the one most often omitted. If a reasonable patient would want to weigh conservative management, delayed surgery, a different approach, or a different implant, those belong in the conversation.

The therapeutic exception, and why you should not rely on it

Montgomery preserved a narrow exception: a doctor need not disclose a risk if, in the reasonable exercise of medical judgement, disclosure would be detrimental to the patient's health. But the Court was pointed about its limits — the therapeutic exception cannot become the basis of the general rule, and it is not a licence to withhold information because the surgeon fears the patient will decide differently.

In practice the exception is close to unusable as a defence in elective orthopaedics. If you find yourself reasoning that a patient would be upset or would refuse a beneficial operation, you are describing the situation Montgomery was decided against, not an exception to it.

The related and legitimate situation is a patient who genuinely does not want the detail. A patient may waive information, and that is their right — but record that they were offered it and declined, because an undocumented waiver is indistinguishable from a conversation that never happened.

How jurisdictions compare

The United States is the genuine outlier: there is no national answer, and the standard is a matter of state law. A surgeon licensed in more than one state may be held to different disclosure standards in each.

Accurate as of July 2026. Case law and statute change. Confirm the current position in your jurisdiction before relying on it.

Who can take consent

A recurring failure that has nothing to do with the legal test: consent taken by someone who cannot answer the questions.

The person taking consent should be capable of performing the procedure, or trained specifically in consenting for it and able to answer questions about alternatives and complications with authority. Sending the most junior member of the team to obtain a signature on the morning of surgery, for a discussion they cannot competently have, is indefensible whatever the form says — and it is a pattern that appears repeatedly in claims.

Equally, consent obtained weeks earlier in clinic should be confirmed on the day, not merely reproduced. Circumstances change, patients reconsider, and a signature obtained six weeks ago does not establish that the patient still wants the operation.

What a defensible record looks like

The consent form proves that a form was signed. It proves very little else. What defends a case years later is a contemporaneous clinical note that shows a conversation happened. It should capture:

• The diagnosis and the operation proposed, in the words used with the patient
• The specific risks discussed, including any the patient raised
• The alternatives offered, expressly including non-operative management
• What the patient said mattered to them — their occupation, their goals, what they asked about
• Any written information provided, identified by name and version
• That the patient had the opportunity to ask questions

The fourth item is the one that wins cases, because it is direct evidence that you engaged the subjective limb of the test. A note reading "discussed risks of infection, VTE, stiffness, revision; patient is a tiler and asked specifically about kneeling — explained kneeling often not restored after TKA; alternatives incl. continued analgesia and injection discussed; information leaflet given" is worth more than any number of ticked boxes.

For the broader principles of record-keeping, see Defensible Clinical Documentation.

The failure modes, ranked

In roughly the order they appear in real claims:

1. No alternative discussed — particularly non-operative management, and particularly where the evidence for surgery is equivocal.
2. Generic risks only — a recited list with nothing specific to this patient's life or occupation.
3. The patient's actual concern never elicited — because nobody asked what they did or what they wanted back.
4. Consent taken by someone unable to discuss it — junior, unfamiliar with the procedure, on the day.
5. No record of the conversation — only a signed form, and no note of what was said.
6. Materially changed circumstances — a different implant, approach or extent of surgery than was discussed, with no fresh conversation.

None of these is a technical surgical error. All of them are avoidable in the length of an outpatient appointment.

The practical shape of a good consent conversation

1. Establish what they want back. Occupation, sport, hobbies, responsibilities. This is not small talk — it is how you discover what is material.
2. State the diagnosis and the proposed operation plainly, without jargon.
3. Give the realistic benefit, not the best case.
4. Cover the alternatives, expressly including doing nothing, and what would happen with each.
5. Discuss risks, weighted toward what matters to this patient rather than a recited list.
6. Ask what concerns them most, and then wait for the answer.
7. Offer written information and time to decide, where the surgery is elective.
8. Write it down — a genuine note, not a form.
9. Confirm on the day, briefly, that nothing has changed.

The summary

The law asks a straightforward question: did this patient have the information they needed to make this decision? Not whether other surgeons would have said the same, not whether the risk was statistically small, and not whether the surgeon thought the patient would choose wisely.

The surgeons who do this well are not doing anything legally sophisticated. They ask what the patient does for a living, they mention what would happen if nothing were done, and they write down what the patient said mattered. That takes a few extra minutes in clinic and it is the single highest-yield medico-legal habit in orthopaedic practice.

---

This article describes legal frameworks for educational purposes and is not legal advice. Standards vary by jurisdiction and change over time — take advice from your indemnity provider on any specific situation.