Have you ever had a sore knee?
Yeah, me too...
Very often, when we have pain, we hope to get a specific structural diagnosis. There is something comforting, but also a little scary, about having a specific diagnosis. People often think that getting that diagnosis is going to solve their problems, since you will know what to "fix". However, this runs into murky territory, as the relationship between tissue damage or structural abnormalities and pain is not as clear as you may think.
Let's take the knee as our example...
Culvenor et al. (2018) carried out a systematic review and meta-analysis of 63 studies investigating the prevalence of osteoarthritic features on MRIs of asymptomatic individuals (i.e. people with no pain). The pooled prevalence of cartilage defects was 24%, and 10% for meniscal tears. When we look to those over 40 years of age, we see these rates increasing
to 43% and 19%, respectively. Along with this, the presence of bone marrow lesions and osteophytes were 18% and 25%. All in all, this points to a prevalence of features of osteoarthritis of 4-14% in those <40 years, and 19-43% in those >40 years. To reiterate, these individuals were asymptomatic, shedding further doubt on the presumed 1:1 relationship between structural pathology and pain. This also further reinforces the idea that these changes should be expected to take place as part of
aging, and they needn’t be associated with pain or disability.
If we look beyond the general population, and look specifically to athletes, these findings become even more interesting. Most of you reading this are active individuals, probably training pretty hard, so this may be even more relevant to you. In a group of 24 collegiate basketball players (12 male, 12 female), 100% of asymptomatic knees imaged had at least 1 structural abnormality (Pappas et al. 2016). Yes, 100%. This included fat pad edema (75% pre-season and 81% post), patellar tendinopathy (83%, 90%), quadriceps tendinopathy (75%, 90%), meniscus abnormalities (50%, 62%, no tears), bone marrow edema (75%, 86%) and cartilage defects (71%, 81%). While these are abnormally high rates versus some other studies, a high prevalence is still consistent in such studies. Kaplen et al. (2005) carried out a similar investigation, but this time in professional basketball players. In this case, the prevalence of cartilage lesions was 47.5%, and meniscal lesions 20%.
And finally, not only does this carry over to other sports, but also to adolescents, as demonstrated by a study of 28 asymptomatic 14-15 year olds. Soder et al. (2011) analysed the MRIs of the knees of 28 asymptomatic adolescents, 14 of which played soccer, and 14 of which were controls. In those who played soccer, 64.3% had at least one abnormality, versus 32.1% in the
control group. Again, this points to the fact that so-called abnormalities can be quite prevalent, even in asymptomatic individuals.
While this is explored in far more detail in a recent article in the Triage Militia, what I would like you to take from this is some reassurance that if you have had an MRI in the past to tell you that "you have the knees of an old man", or anything along those lines, it's likely not as big of a deal as you think it is. Joints change in their appearance over time. Hair goes grey, discs
degenerate, and cartilage gets a little fuzzy. It happens at different rates in all of us, and it doesn't mean that we are going to have pain. If you have pain, recognise that getting rid of that pain is not dependent on fixing a structure, as it is the relationship between structure and pain is a lot less clear then you have been led to believe.
Until next time...
Kind Regards,
The Triage Team
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