What does my x-ray or scan really mean?
Often when we get a scan of our knee the report can sound scary – there is often a lot of jargon and medical terms used that can be difficult to understand. It can be hard to see how this picture or scan relates to YOU and what it means for your journey and future.
What x-rays and scans DO NOT tell us much about:
- The amount of pain you feel now
- The amount of pain you will likely feel in the future
- How much activity you can do
What x-rays and scans DO tell us about:
Findings that are normal with age:
- Many of the reported findings may sound abnormal, but they occur naturally with age.
- E.g., arthritic or degenerative findings, cartilage defect, bony spur
- We know this to be the case because people with very little pain or without any pain at all show the same findings on scans as they get older.
- Thus, these findings are like “wrinkles on the inside”.
- May have been there before your pain started
- May still be there when your pain reduces
The structure of your knee joint:
- It is strong, stable, and surrounded by large muscles and ligaments
- It has adapted to load (e.g., walking, running) over time
- It needs movement to be healthy.
Here are some common (and potentially scary sounding) words on knee scan reports and what they really mean:
‘Arthritic’ or ‘degenerative’ findings
These are terms that describe general findings in bone and cartilage (the tough lining on your knee bones) that occur naturally with the ageing process. Bone and cartilage might appear thinner or less smooth than it once was, but this does not determine your ability to use your knee. Some people might have told you that these findings occur due to ‘wear and tear’ – but recent research shows that this is not true. Marathon runners (technically the ultimate ‘wear and tearers’) have thicker cartilage than people who do not run marathons. In fact, we now know that physical activity is the BEST thing for your knee. Instead, it is thought that these findings can contribute to pain when inflammation is present, as inflammation can increase the over-protectiveness of the pain system
These are growths of bone that can make the edges of your knee joint look a bit rough or stick out on a scan. They typically start as cartilage and then change into bone – they are thought to occur to provide stability (support) to your joint. They are common as we age. These findings in bone tell us very little about your current or future pain and they don’t predict OA progression. Rather, they can actually make your knee more stable by creating a solid platform.
Cartilage is the lining of your joint that can sometimes become thinner and less smooth as we get older, which might be described as ‘defects’ in a scan report. Cartilage is really tough stuff, so even if it is a bit thinner than it once was, it still does its job. Also, you will always have some cartilage left – knees are never truly ‘bone on bone’. While not commonly known, cartilage can even repair itself! For more information about the amazing ability of cartilage to ‘wear and repair’ see p. 26 of the Explain Pain Handbook. It is also important to remember that cartilage has no nerve endings, so even if there are ‘defects’, these do not cause pain.
You have two menisci in each knee – they are c-shaped cartilage cups that help you to absorb the loads that go through your joint. These menisci often undergo age-related changes so it is not uncommon to see small tears on a scan. Large studies show that there is no difference in pain or function in people that have the menisci surgically repaired or removed compared to people that do not.
Subchondral sclerosis or bone marrow lesions
Sclerosis or lesion are terms to describe areas of the bone that look different to other areas (they have increased water content). These findings can occur with age, but are often associated with higher levels of inflammation. These findings in your bone can resolve (or disappear) on their own and/or when your inflammation decreases.
Reduced joint space
Sometimes radiographers will report that there is ‘reduced joint space’ between the two main bones of the knee (i.e. the tibia and femur). This is a completely normal part of ageing. Remember that there is ALWAYS a gap in there, even if it doesn’t look like there is on a scan. Knees are never truly ‘bone on bone’.
It is important to remember that radiographers (the people who look at your scan and write the report) are REQUIRED to report everything they see in detail, even if it might not be relevant to your problem.
What does this mean for me?
You are MUCH MORE than just a picture of your knee. Your knee and surrounding tissues adapt and change to what you do – this is called bioplasticity. The very best thing to promote such change in your knee tissues and in your immune and nervous system is to undertaken activity that gradually increases over time. This means that you can live a happy and pain-free life – no matter what your scan shows.