Orthopaedic imaging and meniscal tears for GPs: good knee X-rays, no CT-guided knee injections, and when a tear needs surgery

Speaker

Specialist who performs knee arthroscopy and meniscal repair — an orthopaedic surgeon by role (not named in the recording; the role is inferred from first-person comments such as putting “the telescope” into the knee and “I’m taking away as little as I can”. The speaker’s phone number was on a slide, but no name was spoken).

Audience

GPs and physiotherapists ask questions and are labelled “Speaker 2–4” or “Unknown Speaker”; none are named. No sponsor or disclosure statement was captured.

Session context

Otter title Orthopedic Imaging Techniques · id eDgYBygRliy_EC8jUlL0ByJwbOM · ~19 min, recorded 21 March 2026 11:03 am AEST. The recording starts mid-discussion (the first sentence is a fragment about CTs and ultrasounds in older patients) and ends when the chair announces that the next session starts at 11:30 and asks everyone to “bring the food back to the table”. The speaker also mentioned having things to say about ACL/MCL injuries, but this was not covered in the recording.

Key messages for GPs

• Request a good quality, weight-bearing, full-view AP knee X-ray for arthritis. It “doesn’t cost much” and gives “a world of information” — in the speaker’s words, “90% of the radiology we need for the arthritis workup” (as stated).
• Check the plane: the tibial plateau should be square-on so you see a single line; if two edges of the tibia show like a disc, the angle is wrong and the film should be retaken.
• CT-guided knee injections are hard to justify — ionising radiation for a joint “right under the skin surface”.
• About 30% of people have a meniscal tear and no symptoms (as stated). Do not leap from “MRI shows a tear” to “you need a scope”.
• Five things should line up before arthroscopy: symptoms that fit, a knee that isn’t arthritic, an MRI that confirms the tear, a proper non-operative trial, and a shorter duration of symptoms.
• “Ignore the report. First listen to the patient.” The symptoms, examination and imaging must “marry up”.
• Root tears are a different problem and need earlier specialist attention.
• The specialist invites GPs and physios to message an X-ray and MRI when they are stuck.

A good knee X-ray: plane, weight-bearing, full view

The speaker asked that GPs focus on good quality X-rays. For an AP film, the tibia should be orthogonal — at right angles — so it appears as a straight line. Often patients are rushed through and the tibia is tilted, so “you can see two parts of the tibia, and it’s like a disc”. In that case the angle has not been set correctly, and the radiographer should stop, change the gantry a bit and take another shot.

• Why it matters: what you are really assessing is joint space narrowing, which is “very hard to appreciate” if the film is oblique and the tibia appears sloped.
• Weight-bearing films are essential. If you are requesting an X-ray for osteoarthritis, the imaging provider “shouldn’t have to” be told it must be weight-bearing and full view — “they should do that automatically”. If not, “you should be on the phone again” and ask for a full-view, good-quality film, or send the patient back.
• X-ray first, MRI later (in older patients): the X-ray is “the lay of the land, whereas the MRI is the granular detail”. A closed-up joint space on an X-ray is far easier to explain to a patient than hyaline cartilage and meniscus on an MRI. “Good quality weight-bearing X-ray, case closed, and then we can order an MRI if they need.” In younger patients, an MRI and X-ray have often been done before they get to the specialist.

CT-guided knee injections

The speaker said this “came up a few times”: some patients are having CT-guided injections. “I don’t like the idea that [there’s] ionising radiation to find an injection into a joint which is right under the skin surface.”

• “I think all of us right now can inject straight into the knee without any aids” — or use ultrasound. The speaker understood that a rebate may be involved.
• CT guidance for a hip or back injection is understandable (“I get it”), but for a knee it is “a bit ridiculous” and “aggressive”. “I wouldn’t have it for any of you or my family.”
• The speaker understood that the reason offered is so that the service can bulk bill, but said “a financial concern is not my problem — I just want to protect that patient from… extra radiation.”
• Action: if a provider keeps doing it, “I’d be saying, thank you very much, I’ll be sending [patients] elsewhere next time.”
• An audience member said they have patients who have it done every six months; another said they were not aware of the practice and wondered about the quality of how it is done (the passage is partly garbled).

Meniscal tears are common — and often silent

“Everyone comes to the desk and says, I’ve got a meniscal tear; my friend had an arthroscopy in [their] bedding… when are we going to do it?” The speaker’s response starts with a statistic: if you took everyone in the room, about 30% would have a meniscal tear and none would have symptoms (as stated). So “be careful about saying ‘this is what we’re going to do — you’ve got a meniscal tear’”. A meniscal tear needs “a few things going for it before we get too excited”.

Why the posterior horn tears

An audience member asked whether meniscal injury is common with hyperflexion. “Very common.” The explanation:

• The meniscus is C-shaped. When you bend the knee, the femur does not stay centred and spread the load; it rolls back (seen on deep-flexion MRI in experimental studies, as stated).
• Beyond about 90 degrees the femur “slips back” and does not distribute weight to the front or middle; the load goes onto the posterior horn. The transcript gives a figure for the share of pressure borne by the posterior horn (“90 to 95%”) but the wording is garbled.
• Squatting, crouching, kneeling and plunging movements are “high yield” for injuring the meniscus, stirring up symptoms from an existing tear, and causing locking or displacement.
• The medial meniscus takes more load and is more fixed, so it has less capacity to move out of the way and is injured more often. The lateral meniscus is very flexible. The most common site is posterior and medial — “maybe 80, 90%” (as stated).

Five things before arthroscopy

The speaker said it “boils down to these five”. They are the things that should line up for someone to be a “home run” for arthroscopy:

1. Symptoms of a meniscal tear. The patient can point to it — localised pain, “like a dagger” — rather than “it’s all around the knee, or it radiates up to the thigh, or I can’t really tell what it is… it’s just a mild swelling”.
2. The knee isn’t worn out. “We’re not doing knee scopes on arthritic patients anymore.” The old “10,000-kilometre cleanup”, where the knee was washed out, “doesn’t do anything”. If anyone suggests it for an arthritic patient, consider a second opinion.
3. MRI confirms a meniscal tear that fits the clinical picture — “hallelujah, and it all agrees”.
4. Adequate non-operative management. Typically six to eight weeks of anti-inflammatories, physio, paracetamol and ice (ASR: “the ICU”, presumably ice), and possibly a steroid or PRP injection — “take it as far as the patient needs”. If they are totally disabled — can’t work or look after children — an earlier assessment may be reasonable. Not for a root tear or a bucket-handle tear.
5. Shorter duration of symptoms. Symptoms of two weeks are very different from two years. The speaker likened it to carpal tunnel: after two years of symptoms “you release a carpal tunnel, [and] symptoms take a long time to resolve”, so expect a slower response the longer they have been there. (The ASR numbering of the five items is not clear; this is the order they were spoken.)

Do meniscal tears heal?

An audience member asked about the natural progression: do they heal, or stay split? “Very poorly.” The speaker showed a cross-section image:

• Outer third — some blood supply. Middle third — not much. Inner third — none.
• The meniscus is not like skin, bone or muscle; it is a poorly healing tissue (the ASR reads “a 40 year level substance”, which is garbled). “Inner margin tears almost never [heal]; outer margin tears, and particularly meniscocapsular injuries, have some potential.”
• For a simple answer: “the vast majority” don’t heal. The analogy used: “a stone in your shoe” — it won’t spontaneously pop out, but it may “rumble around for a while, irritate you”, and then get stuck somewhere where it feels okay. Many tears then stop being a problem “that we need to address right now”.

What arthroscopy does — and the arthritis question

An audience member asked: if we do an arthroscopy and “just take out the fragment”? The speaker explained:

• The aim: “If I’m doing my job right, I’m taking away as little as I can” — only “a tiny arc”, the part that is torn. “If you’re a cowboy, you could scuff the cartilage above… or take out too much.”
• The physio’s warning: a physio may say “don’t have an arthroscopy, you’ll get arthritis.” The speaker’s reply: “that is true, but actually you signed up for arthritis when you tore the meniscus, because that piece of meniscus isn’t padding your knee anymore.” If the torn piece is not giving symptoms, you will probably get a little more arthritis than you would otherwise, “but I’ll leave it in”. If it is giving symptoms and is taken out, “you’ll probably still get the same amount of arthritis”.
• The history: about 30 years ago the meniscus was thought of as an “embryologic remnant”, so surgeons removed a lot of it if it tore. “Now we know it’s a pad; it gives conformity, it gives stability.” The principle now: leave everything you can, and suture repair whenever possible, especially in young patients.

Suture repair: who is suitable

• Suture repair is “lovely to do, technically not difficult”, but is typically reserved for younger patients because the meniscus is a poor healer and the younger patient’s ability is “quite good”.
• Under 25: “every time, I’ll try to repair.” 25 to 35: maybe, depending on the tear. For an older patient — “if you’re my age” — “probably not” often, because the rate at which they heal is limited.
• The cost of a failed repair: “nine months of rehab, you did everything right, I did everything right, and then it tears out again… so frustrating beyond belief.” So be cautious with patient selection, “even though we’ve moved much more toward repair”.

Athletes, adolescents and duration of symptoms

• Professional athletes are “a very different mode of treatment, 100%”, because they do not have the luxury of waiting three months and then needing surgery — it might be the start of the off-season. The speaker would make a judgment call about the likelihood of re-injury and flare (a figure is given as “34%”, as captured — unclear).
• Adolescents (the example was a 16-year-old): “I don’t want to be operating on him without a compelling reason. I wouldn’t have it done to my own child.” Athletes and the “promising” child “are different too”, which is a more nuanced conversation, and the speaker will change the options profile.
• Duration: as above — a patient with two years of symptoms is very different from a patient with two weeks.

Case: a 50-year-old with six months of knee pain

An audience member described a 50-year-old, 96 kg patient with six months of knee pain and a meniscal tear, no arthritic change. The speaker said it is very hard to advise on so little information, but gave a rough algorithm:

1. Make the diagnosis — find the pain generator. Is it truly meniscus? Is there something else, such as the hip or back, referring pain? “If I MRI all of these people in this room with no knee pain, there’s going to be some meniscal tears.” Ignore the report; listen to the patient. Does the patient’s own description fit a meniscal problem? (An audience comment about the medial side and swelling is garbled.) It “has got to marry up”.
2. Non-operative options if it truly is meniscus: physio, PRP injections, anti-inflammatories, weight reduction and other ancillary measures. They can be “surprisingly effective”, but be clear to the patient that “none of these things fix the meniscus”. They may “blanket it enough” to cope.
3. Then look at the tear type and morphology: would it suit a partial meniscectomy? At this age, “almost certainly not going to offer repair”; maybe a partial meniscectomy if there are unremitting symptoms. At 50 with no arthritis, there is “probably not much arthritis” yet — but weight is a problem.
4. Make sure it is not a root tear. “At that age, female, we want to make sure it’s not a root tear.”

Root tears are different

The speaker showed an image of a root tear. In a typical (“garden-variety”) tear, part of the meniscus is torn. In a root tear, the entire root is severed: “when the weight comes down on the knee, the meniscus slides out of position… the whole meniscus displaces out of position. The patient runs into arthritis very quickly.” That is “very different to the garden-variety tears”.

That is why a root tear (and a bucket-handle tear) is not managed with the usual “wait and see” trial — if you are not sure which type of tear it is, “maybe message someone, just ask: is this okay to sit on?”

Injections: expectations and honest counselling

The last part of the recording covers an injection treatment. The product is not named in the captured passage; in context it seems to be the PRP injection mentioned earlier, but this is not certain. The speaker’s counselling points:

• Efficacy: “two thirds of patients, for most pathologies, [get] some relief. The other third say, ‘that was a waste of time’ — so make sure you tell them that.”
• Cost: “it’s a bit expensive — it’s $400” (as stated). So you would not use it for severe arthritis; you would use it for mild to moderate disease, because it has more efficacy the milder the arthritis.
• Role: “it’s not a fix of arthritis. It is a symptom management tool. It’s like giving paracetamol. It doesn’t fix the arthritis; it manages it.” If pain is minimal and function good, “that’s fantastic”.
• Schedule: response is “very variable”. Do one, then another a month later; “if it’s a winner”, repeat at two, three or four months. Some patients say it did nothing — “so be realistic”.
• Steroid injection: “works much more effectively and lasts far less time. I rarely use steroid.” The duration the speaker gave (“10 to 14”) was cut off — the unit is not captured.

Asking the specialist for help

“My number is on there.” The speaker said the only thanks specialists can give GPs for referrals is that “once in a while, 4:59 on a Friday, you’re stuck with a patient — you’re like, what the hell do I do? Please send a message, text… X-ray, MRI, can you have a look? Tell me what you do, because I’m stuck.” The speaker thinks the other specialists in the room would say the same, and said physios and GPs message them “all the time” and “it works well”. They added that they would not want too many questions about shoulders, because “I’m not good enough”.

GP clinic checklist

1. Request a weight-bearing, full-view, good-quality AP knee X-ray for suspected osteoarthritis; check the tibial plane; phone the provider if it isn’t right.
2. Inject the knee without imaging aids, or use ultrasound, as the speaker described; question routine CT guidance for a knee.
3. Before blaming a meniscal tear, ask: are the symptoms localised and mechanical? Is the knee arthritic? Does the MRI match?
4. Remember that ~30% of people have a silent tear (as stated): “ignore the report; listen to the patient”.
5. Rule out other pain generators (hip, back).
6. Try 6–8 weeks of non-operative care for a simple tear; explain that none of it “fixes the meniscus”.
7. Think about root tears (the speaker specifically said to check for one in the 50-year-old woman) and bucket-handle tears — these are not managed with the usual wait-and-see trial; ask the specialist.
8. Set realistic expectations for injections: about two-thirds benefit; cost; a symptom tool, not a cure.
9. Remember that repair is mainly for the young (under 25 definitely; 25–35 selectively).
10. When stuck, message the specialist with the X-ray and MRI.

Transcript caveats

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