explainer · updated 18 September 2026 · illustrative scenario, not a real patient

Before you agree to knee surgery: seven questions, and what the trials actually found

What to ask when arthroscopic knee surgery is offered for a degenerative tear — and the trial evidence on surgery versus structured physiotherapy, including the number that matters most for deciding.

A recommendation for knee surgery can leave little time to prepare questions. This guide focuses on one defined situation: degenerative meniscal tears with mild-to-moderate osteoarthritis. It cannot determine whether an operation is appropriate for you.

The trial

The MeTeOR trial randomised 351 patients aged 45 and over who had a meniscal tear visible on imaging together with mild-to-moderate osteoarthritis. One group had arthroscopic partial meniscectomy followed by physiotherapy. The other had a standardised physiotherapy regimen alone, with the option to cross over to surgery later.

At six months, the surgery group improved by 20.9 points on the WOMAC physical-function scale and the physiotherapy group by 18.5. The difference was 2.4 points, with a 95% confidence interval from −1.8 to 6.5 — that is, the data are consistent with no difference. Results at twelve months were similar, and the frequency of adverse events did not differ significantly between groups.

In this trial, 30% of those assigned to physiotherapy had surgery within six months. Crossover makes comparison harder, but shows that the trial allowed reassessment rather than a permanent choice against surgery. These results do not prove the treatments are equivalent for every patient.

Seven questions to ask

1. What specific finding is the operation meant to fix? Ask how the diagnosis, symptoms and examination fit together.
2. Has anyone read the images, or only the report? A report is a summary written for the doctor who ordered the scan.
3. What non-operative treatment has been tried, for how long, and how was it measured? "Physiotherapy" without duration and adherence is not an answer.
4. What would count as failure, and when would we know? A trial of conservative treatment needs a decision point.
5. Is it safe to wait, and for how long? For some conditions it does. Ask which.
6. What is the plan if the findings at surgery differ from the imaging?
7. What would make you change this recommendation?

An illustrative scenario

The following is an illustrative scenario, not a real patient. It is written to show how the questions work in sequence, and describes no one.

A person is offered arthroscopy after an MRI describes a degenerative tear. Before booking, they ask how the scan relates to their symptoms, what non-operative options are suitable and when reassessment should happen. They request a written explanation and bring it to their treating clinician. No treatment outcome is assumed in this example.

The useful feature of the scenario is the question sequence, not a promised result. A records review may identify questions for an examination; it cannot replace every part of a clinical assessment.

Where this reasoning does not apply

These findings concern adults with degenerative meniscal tears and mild-to-moderate osteoarthritis. They do not settle the management of acute traumatic tears in younger patients, a genuinely locked knee, or advanced joint destruction, where the balance of considerations is different. Trial populations also differ from individuals: an average result across 351 people is not a prediction for you.

If you want the images reviewed

An independent written review means a clinician reads your imaging and reports and writes down what they see, what they would do, and what they would not do. Ask the provider whether the service includes a consultation, examination or ongoing treating relationship. For the logistics of arranging care abroad, see Cross-Border Care Guide.

Sources

• Surgery versus Physical Therapy for a Meniscal Tear and Osteoarthritis New England Journal of Medicine, 2013