Informed Consent and Shared Decision-Making

Informed consent is the ethical and legal permission a patient gives before an intervention. Ethically it rests on respect for autonomy — the first of the four principles of biomedical ethics (Beauchamp and Childress): autonomy, beneficence, non-maleficence and justice. The legal origin of the idea is usually traced to Justice Cardozo, who wrote in Schloendorff v Society of New York Hospital (1914) that "every human being of adult years and sound mind has a right to determine what shall be done with his own body." Touching a patient without consent is, in law, a battery; failing to warn of a risk before treatment is negligence.

The single idea examiners most want you to hold onto is that consent is a process, not a form. The signed form is evidence that a conversation happened; it is not the consent itself. A form signed by a patient who was never told the material risks, or who lacked capacity, or who was put under pressure, is worthless — and operating on that basis is an assault.

Consent is examined in every orthopaedic exam (FRACS, FRCS, ABOS, EBOT) because every operation, every injection and every reduction is a consent event. It sits in the professionalism and ethics domain, and a weak answer here fails a viva that was otherwise clinically perfect.

For a consent to be legally and ethically valid, three elements must all be present. The mnemonic CIV holds them together: Capacity, Information, Voluntariness.

• Capacity (competence). The patient must be able to understand, retain, use and weigh the relevant information, and communicate their decision. Capacity is presumed in every adult, is decision-specific (a patient may have capacity to consent to a carpal tunnel release but not to a complex revision arthroplasty) and is time-specific (delirious patients may regain capacity). It must be supported — explain in a way the patient can follow, and never simply declare someone incapacitated because you disagree with their choice.
• Information (disclosure). The patient must be told what a reasonable person in their position would want to know: the diagnosis, the proposed treatment and its purpose, the material risks, the reasonable alternatives (including the option of no treatment), and the likely outcome of doing nothing. The legal standard for what counts as a "material risk" is set by Montgomery and is covered in the next section.
• Voluntariness. The decision must be made freely, without coercion or undue influence — from relatives, staff, or circumstance. Confirm the patient knows the decision is theirs, that they can take time, and that declining will not change how they are treated.

Two further conditions frame the three elements. Consent must be specific to the procedure actually performed (consent for a knee arthroscopy does not cover converting to an arthroplasty), and it must be continuing — a competent patient can withdraw consent at any time, including on the table before induction.

What you must tell a patient about risk has moved, over half a century, from a doctor-centred test to a patient-centred test. Knowing the sequence is a standard viva question.

For most of the twentieth century, UK law applied the Bolam test (Bolam v Friern Hospital Management Committee, 1957): a doctor was not negligent if acting in accordance with a practice accepted as proper by a responsible body of medical opinion. This professional standard was extended to consent — if responsible doctors would not have warned of a particular risk, neither had to the doctor in the dock. In Bolitho (1997) the House of Lords qualified this: a court may reject a body of expert opinion if it lacks a logical basis, reasserting the court's right to judge the reasonableness of medical practice.

The decisive shift came in Montgomery v Lanarkshire Health Board (UK Supreme Court, 2015), which discarded Bolam specifically for risk disclosure. A doctor must now take reasonable steps to ensure the patient is aware of any material risks of the recommended treatment and of any reasonable alternative. A risk is material when either:

1. a reasonable person in the patient's position would be likely to attach significance to it, or
2. the doctor is, or should reasonably be, aware that this particular patient would be likely to attach significance to it.

The first limb is the reasonable-patient standard; the second is what makes it shared decision-making — it forces you to ask what this patient would care about. Therapeutic privilege (withholding information for the patient's own good) is not a defence except in the narrow case where disclosure would cause serious harm. The treatment itself — how you operate — is still judged on the Bolam professional standard; it is only the consent conversation that Montgomery governs.

This patient-centred standard is now effectively global, though it arrived by different routes:

The practical convergence is the point an examiner wants: disclose what a sensible patient in front of you would want to know, name the alternatives, and tailor it to the individual.

Shared decision-making is the modern, positive form of consent — not a doctor listing options and a patient signing, but a deliberation between clinician and patient in which the clinician brings the evidence and the expertise, and the patient brings their values, goals and circumstances. It directly satisfies the "particular patient" limb of Montgomery.

The structure of the conversation is easily remembered as BRAN — the four things every consent discussion must cover:

In the UK, the General Medical Council's guidance Consent: patients and doctors making decisions together (2020) sets out the dialogue in detail: the diagnosis and its uncertainties, the options (including no treatment), the purpose, the potential benefits, the common and serious risks, and the outcome with and without treatment. In the United States the AAOS Code of Ethics and Professionalism requires orthopaedic surgeons to obtain informed consent, to discuss material risks, benefits and alternatives, and to respect patient autonomy and refusal. The Choosing Wisely campaign (in which AAOS participates) pushes the same direction — encouraging clinicians and patients to choose care that is evidence-based, necessary and free from harm, and to avoid low-value interventions.

Decision aids — written, video or digital — improve knowledge and produce more realistic expectations, and reduce decisional conflict for preference-sensitive choices such as arthroplasty. Offering one is good shared decision-making and good evidence of a thorough consent process.

Most consent is straightforward; examiners probe the edges. Four situations recur: the emergency, the minor, the patient who lacks capacity, and the patient who refuses treatment.

For capacity, the UK Mental Capacity Act 2005 gives a two-stage test: first, is there an impairment or disturbance of the mind or brain; second, if so, is the person unable to make this decision — meaning they cannot understand, retain, use or weigh the information, or communicate the decision. In the UK, no relative can consent for an adult who lacks capacity; the clinician decides on the best interests standard (MCA s 4), weighing the patient's past wishes, values and beliefs, the views of family and carers, and choosing the least restrictive option. In contrast, most US states and Australia recognise a surrogate or proxy decision-maker, an enduring power of attorney or a court-appointed guardian.

For refusal, a competent adult's refusal of treatment — even of life-saving treatment, even if the reason is one you disagree with — must be respected (Re T, 1992; reinforced by Malette v Shulman in Canada). A refusal can be vitiated if the patient lacked capacity, was materially misinformed, or was under undue influence. A valid advance decision (advance directive) refusing specific treatment stands as if the now-incapacitous patient were refusing it in person.

A good consent conversation is necessary but not sufficient. The operation itself is protected by layered safety systems, of which the WHO Surgical Safety Checklist is the centrepiece. Haynes and colleagues showed, in a global study of 7,688patients across 8 hospitals, that introducing the checklist cut surgical complications from 11.0% to 7.0% and in-hospital deaths from 1.5% to 0.8%.

The checklist has three phases, and confirming that consent has been obtained is the first item of Sign In — consent is wired directly into the safety system:

Site marking and the team pause exist to prevent wrong-site and wrong-procedure surgery — never events that almost always trace back to a consent or verification failure. Beyond the checklist, handover and communication tools such as ISBAR (Identify, Situation, Background, Assessment, Recommendation) structure the team communication that keeps a consented plan safe as it moves between people and places.

Underneath all of this sits James Reason's Swiss-cheese model of human error (Reason, 1990; BMJ 2000): disasters rarely come from a single failure; they occur when the holes in several defensive layers — consent, marking, the checklist, team communication — align. Consent is one of those layers, which is why a thorough, documented conversation is a safety intervention, not paperwork.

The consent form records that a signature was given; the medical record records the conversation. After a proper Montgomery-standard discussion you should be able to write, in the notes, what you explained — the diagnosis, the options discussed including no treatment, the specific material risks you raised for this patient, that alternatives were offered, and that the patient's questions were answered. For high-stakes or contested decisions (a refusal of recommended surgery, a best-interests decision, a Jehovah's Witness refusing blood) the quality of this entry is what protects both the patient and you.

Where relevant, note decision aids offered, family members present, the time taken, and any capacity assessment with its outcome. A signed form without a corresponding note is a consent of unknown quality; a clear note is the evidence that shared decision-making actually happened.

This condenses the topic for revision and viva practice — the points that score, the memory hooks, three worked vivas, and a one-screen cheat sheet.