You've hurt your knee. You go through the process, wait for your appointment, sit through the MRI, and then wait again for the results. Finally, they come back — and something doesn't add up.
Maybe the scan shows a tear, but you're walking around relatively fine and wondering what all the fuss is about. Or maybe the report says everything looks okay, but your knee still doesn't feel right. It's swollen, it's painful, and something just feels off.
If this sounds like you, I want you to know: you are not imagining it, and you are not alone. This situation — where MRI scan results and your actual symptoms don't seem to match — is one of the most confusing and frustrating parts of an ACL injury, and it's something I see come up again and again. Let me explain what's actually going on.
Why MRI Scans Don't Always Tell the Full Story
An MRI scan is one of the most powerful diagnostic tools we have. It gives clinicians a detailed picture of the soft tissue inside your knee — the ligaments, the menisci, the cartilage. When it comes to diagnosing ACL tears, a good quality MRI in the right clinical context is highly accurate.
But here's the thing that often gets lost in translation between the radiologist's report and your kitchen table: an MRI is a snapshot. It captures what your knee looks like at a single moment in time, in a controlled, static environment. It doesn't capture how your knee performs under load, how stable it feels when you change direction, or how your nervous system is coping with the injury. It doesn't capture pain.
This is why MRI scan results and symptoms don't always line up neatly.
When Your Scan Shows a Tear But You Feel Relatively Fine
This is probably the most commonly misunderstood scenario I come across. Someone sustains a knee injury, gets an MRI, and is told they have a complete ACL tear. But they're still walking. They can manage the stairs. They went to work the next day. Surely something is wrong with the scan?
Not necessarily. The ability to walk — even to function reasonably well in daily life — does not rule out an ACL tear. The ACL is primarily a stability ligament, not a weight-bearing structure in the way your bones and muscles are. What it does is prevent your tibia (your shin bone) from sliding forward relative to your femur (your thigh bone) and controls rotational movement. When it's torn, the instability it causes tends to be most obvious under load and during dynamic activities — pivoting, cutting, landing from a jump, changing direction at speed.
For many people, especially in the early days and weeks after injury, the surrounding muscles — particularly the quadriceps and hamstrings — will work overtime to compensate and provide some level of functional stability. The knee feels manageable. Pain may be present but tolerable. This is why some people are genuinely surprised when they're told the ACL is gone.
The catch is that this compensation has limits. As you return to higher-level activity, that instability becomes harder to mask — and that's when things can go wrong.
When Your Scan Looks Fine But Your Symptoms Are Telling a Different Story
Now let's flip it. This is the scenario that causes the most anxiety and — if I'm being honest — the most frustration within the healthcare system.
You've had a knee injury. Your knee is swollen, stiff, and painful. Something happened to it. You have an MRI, and the report comes back saying the ACL looks intact. So why does your knee still feel like this?
There are several things worth understanding here.
First, MRIs can miss things. The accuracy of an MRI depends on the quality of the machine, the positioning of your knee during the scan, and — critically — the experience of the person reporting it. A partial ACL tear can be particularly difficult to identify on imaging. The ligament may still appear structurally present but have significant fibre damage, altered signal on the scan, or loss of tension that doesn't always scream out on standard imaging. ACL sprains — where the ligament is stretched rather than fully torn — can be even harder to pick up. Yet they still cause pain, swelling, instability, and a very real impact on your daily life.
Second, an ACL injury very rarely happens in isolation. The forces that cause an ACL tear are significant, and they often cause additional damage at the same time — to the menisci, the joint cartilage, bone bruising (bone contusions), or other ligaments like the MCL. Some of these associated injuries may not be the focus of the radiology report, or they might be noted but downplayed. But they could absolutely be the source of your ongoing pain.
Third — and this is important — pain doesn't just come from tissue damage. After a significant knee injury, your nervous system becomes sensitised. You develop heightened pain responses around the joint as part of the body's protective mechanism. This is a real, physiological process. It's not in your head. But it means that your pain experience doesn't always map directly onto what a scan can show.
The Reddit Reality Check
I've spent a lot of time reading through the real experiences of people going through ACL injuries and recovery — and the "scan vs symptoms" disconnect is a theme that crops up constantly. People post about being told their knee looks fine on MRI while a physiotherapist is convinced there's a full tear. There are threads about having two doctors say no tear, while another practitioner says it's completely gone. There are people describing how they went for months before anyone took their symptoms seriously.
One particularly striking thread is titled simply: "HELP! 2 doctors saying no ACL tear, PT saying it's fully torn." 126 comments deep. People who've lived this exact situation sharing their stories.
If you're in that situation right now, I want to be direct with you: your symptoms are real data. They matter. A scan is a valuable piece of the puzzle, but it is one piece. How your knee feels, how it moves, how stable it is under load — these are all equally valid sources of clinical information.
The Clinical Assessment Is Not Optional
When there is a mismatch between your scan results and your symptoms, the most important thing is a thorough physical assessment by an experienced clinician — not just a review of a piece of paper.
There are clinical tests that are specifically designed to assess ACL integrity. The Lachman test, the anterior drawer test, and the pivot shift test all assess the stability of the knee directly. In experienced hands, these tests have very high sensitivity for detecting ACL tears. In some studies, a skilled clinician's physical assessment is actually more accurate than MRI for diagnosing ACL tears.
If your scan has come back unclear or negative but your knee still isn't right, push for that proper physical examination. Ask to see a specialist in knee injuries — an orthopaedic surgeon, a sports medicine physician, or an experienced musculoskeletal physiotherapist. Don't let a scan result be the end of the conversation.
What About After Surgery? Scans Don't Reflect How Well You're Recovering
There's another dimension to this that I want to address, because it catches a lot of people off guard during recovery.
Many people post-ACL reconstruction will have a follow-up MRI at some point during their recovery. The scan might show a graft that looks structurally intact — the "plumbing" is in place. And then they wonder: so why can't I run? Why does my knee still swell when I do too much? Why does it still hurt at 8 months?
This is a crucial point. An MRI showing a structurally intact graft tells you almost nothing about whether you are ready to return to sport. What it cannot show is whether the graft has matured and remodelled (a process called ligamentisation that takes 18–24 months), whether your neuromuscular control has been restored, whether your quadriceps strength is within the acceptable range relative to your other leg, or whether your movement patterns have been properly rehabilitated.
The graft can be intact on a scan and you can still be at very high risk of re-injury if you rush back before the biological and functional criteria are met. That's why in my rehabilitation programme, I use objective performance tests to guide progression — not arbitrary timelines, and not scan images.
So What Should You Actually Do?
If you're in a situation where your scan results and your symptoms are telling different stories, here is my advice:
Don't dismiss your symptoms because of what a piece of paper says. Your body is giving you information. Listen to it. At the same time, don't catastrophise based on the scan result alone either. Context matters enormously.
Seek a comprehensive physical assessment from someone who specialises in knee injuries. Make sure they actually examine your knee — test its stability, its range of movement, how it responds to load. Bring your scan images with you so they can be reviewed in the context of your presentation.
Track your symptoms objectively. Keep a record of your pain levels, your range of movement, any swelling. These measurements over time are incredibly useful in guiding management decisions, and I cover exactly how to do this in my ACL Recovery Roadmap.
Understand that recovery from an ACL injury — whether surgical or conservative — is about far more than what any scan can show. It's about restoring strength, movement, stability, and confidence in your knee. That process takes time, consistency, and the right guidance.
Want to Understand Your ACL Injury Better?
If you're at the beginning of this process — whether you're waiting for a diagnosis, trying to make sense of confusing scan results, or just wanting to know what's ahead of you — my free ACL Injury Survival Guide is a great place to start. It walks you through timelines, explains what's happening at each stage, covers the do's and don'ts, and helps you understand how to give yourself the best possible chance of a great recovery.
You can also use my free ACL Diagnostic Quiz if you want personalised guidance on where you currently are in your recovery and what your next steps should be.
And if you're further along in your journey and looking for a structured, evidence-based rehabilitation programme, the ACL Recovery Roadmap has helped many people get from injury through to confident return to sport — with a clear, level-by-level framework that takes the guesswork out of your recovery.
You're dealing with something complicated. But you don't have to navigate it alone, and you don't have to be left confused by a piece of paper that doesn't match how you feel.
Always seek the advice of a qualified medical professional regarding your individual diagnosis and treatment. This article is for informational purposes only and does not constitute medical advice.
