A patient with knee pain needs an orthopaedic opinion when there is a problem an operation can fix and the patient wants it fixed, when the knee is mechanically obstructed, when a structural injury is repairable and time-critical, or when non-surgical management has genuinely been completed and the patient's function remains substantially impaired. Everything else is a matter of sequence rather than a matter of referral.
National guidance is more specific than most local pathways suggest. NICE recommends considering referral for joint replacement where joint symptoms are substantially impacting quality of life and non-surgical management has been ineffective or unsuitable, and it explicitly says the referral decision should be made on clinical assessment rather than on a numerical severity score.
The harder question is the one guidance does not answer, and it is the reason this page exists: what counts as non-surgical management having been completed, and what does not by itself justify a referral at all.
This page is written for general practitioners, musculoskeletal first contact practitioners, MSK physiotherapists and advanced practitioners: the clinicians who actually make knee referral decisions, and who rarely get to see how those decisions turn out.
It is not written for patients, and it is not a substitute for local pathways or for clinical judgement. Where your service has agreed criteria, those govern.
Serious pathology in a knee is uncommon, and it does not go through an elective referral or an advice service. It goes through the local urgent or emergency pathway, on the day. The categories worth holding in mind at first contact are these.
A hot, swollen, acutely painful knee with restricted movement, fever or systemic upset, and any new pain or effusion in a knee that has a prosthesis in it. Significant trauma with deformity, or a knee dislocation even if it has already reduced.
Inability to lift the straight leg off the bed, or a palpable gap in the extensor mechanism. A genuinely locked knee that cannot be fully straightened. A calf or knee presentation that could be a deep vein thrombosis rather than a joint problem.
Unexplained night or rest pain, unexplained weight loss or a history of cancer. An inflammatory pattern: early morning stiffness over thirty minutes, other joints involved, psoriasis or inflammatory bowel disease. And hip and lumbar spine as a source of referred knee pain.
Recognition of serious musculoskeletal pathology is set out nationally in the ARMA guidance on urgent and emergency musculoskeletal conditions requiring onward referral, which is the document to work to rather than this page. NHS England is explicit that serious pathology should not be routed through specialist advice services at all.
Four things trigger knee referrals every day that national guidance says should not trigger them on their own. Naming them is not a criticism of referrers. It is a criticism of a system in which nobody tells you what happened to the last one.
Radiographic severity is not the referral trigger. A patient coping well with a poor-looking radiograph does not need an operation because of the picture, and delay in that patient costs very little. NICE recommends deciding on clinical assessment rather than on numerical severity scoring, and the same logic applies to grading a film.
A degenerate meniscal tear is a common finding, not a surgical indication. The national guideline from the British Association for Surgery of the Knee is that the large majority of meniscal tears are treated non-operatively first, and that arthroscopic meniscectomy is not a first-line treatment. The trigger is mechanical obstruction, a repairable traumatic tear, or a root tear in a knee without established arthritis, not the word tear in a report.
NICE is unambiguous: do not exclude people with osteoarthritis from referral for joint replacement because of age, sex, smoking, comorbidities, or being overweight or obese. These may affect the outcome of surgery. They are not obstacles to referral, and using them as a filter is an access barrier rather than a clinical criterion.
NICE recommends using clinical assessment when deciding to refer someone for joint replacement, rather than systems that numerically score severity of disease. Oxford Knee Scores and similar instruments are useful for measuring change. They were not recommended as the basis for deciding who is referred.
Referral criteria almost universally require that non-surgical management has been tried. Almost none of them say what that means, so in practice the phrase covers everything from twelve weeks of supervised strengthening to a photocopied exercise sheet handed over eighteen months ago. Those are not the same answer, and a surgeon reading the referral cannot tell them apart.
Three things make the difference legible to whoever reads the referral next. How many weeks of exercise, and whether it was supervised or self-directed. What analgesia was tried, and what it did. And if there was an injection, not just that one was given, but how long the response lasted, because the duration of the response is the discriminating variable and it is almost never recorded.
Therapeutic exercise is core first-line treatment for osteoarthritis under NICE, alongside weight management where relevant. Nobody has failed non-surgical management until they have actually had it.
For suspected osteoarthritis in a patient over forty-five, the useful investigation is a weight-bearing plain radiograph, not an MRI. An MRI in that patient will find degenerate change, and finding it changes neither the diagnosis nor the management.
Where the images are held matters as much as whether they were done. Image transfer between organisations is named repeatedly as a reason a decision cannot be made at the first appointment, so say where the films are and attach the report.
Ask it, at first contact, every time. Preface it with one plain sentence saying that most knee problems do not need an operation and that the answer changes nothing about what is offered today.
It is never a reason to refuse or delay a referral, and it must never be used as one. It changes the order of the plan, not the patient's access. A patient who says no in March may say yes in October, so the answer is recorded with its date and asked again. Nationally, almost a third of first orthopaedic outpatient appointments end in discharge after a single attendance. A great many referrals are already requests for advice. Very few say so.
There is no national standard for what a knee referral must contain. Local pathways ask referrers to demonstrate that core treatment was offered and stop there, which is why referrals are rejected for missing information that was never specified in the first place.
In this surgeon's view, a knee referral becomes decidable when it carries five things: the safety screen, answered rather than left blank; the presentation, including mechanism if there was an injury and whether there is true locking, catching or giving way; what the patient cannot do now and what they want back, in their own words; what has been tried and for how long, with the duration of any injection response; and the imaging, with the date and where the images are held. Add one line saying what you actually want, whether that is advice, a diagnostic opinion, a surgical assessment or a second opinion for the patient.
None of that requires a new examination. All of it is already known to the person writing the referral.
This page covers the adult knee at first contact, in an elective context. It does not cover trauma, children, the painful or infected joint replacement, inflammatory arthritis, or spinal and hip pathology presenting as knee pain, each of which follows a different route.
It is general information for health professionals about referral pathways. It is not clinical advice, it is not a protocol, and where your local pathway differs, your local pathway governs.
The wider policy context is on MSK referral optimisation, which explains why a referral decision can be wrong in two directions and why referral volume is a poor measure of referral quality. The category of software that supports this decision is explained on what MSK clinical decision support is, and where these decisions are made in the NHS is covered on MSK triage explained and first contact practitioners and MSK roles.
Osteoarthritis in over 16s: diagnosis and management, NG226, National Institute for Health and Care Excellence, 2022. Referral for joint replacement, and the recommendation to use clinical assessment rather than numerical severity scoring. Read it here.
Abram SGF, Beard DJ, Price AJ, et al. Arthroscopic meniscal surgery: a national society treatment guideline and consensus statement. Bone and Joint Journal, 2019. British Association for Surgery of the Knee. Read it here.
National consensus on the definition, investigation and classification of meniscal lesions of the knee, 2018. Read it here.
Urgent and emergency musculoskeletal conditions requiring onward referral, Arthritis and Musculoskeletal Alliance, version 2, 2020. Read it here.
Musculoskeletal orthopaedic approach to referral optimisation, NHS England, publication reference PR2103, 2023. Read it here.
Written and clinically reviewed by Dr Arj Imbuldeniya, Consultant Orthopaedic knee and hip surgeon, and last reviewed on 21 August 2026. If anything here is out of date or wrong, particularly if you work in one of these services, please tell me and I will correct it. None of the organisations named or linked on this page has reviewed, approved or endorsed Orwyn.
Orwyn is being co-designed with the clinicians who will use it and with patients, and is designed for NHS Trusts and the services that commission musculoskeletal care.
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