Prevalence of Knee Osteoarthritis Features on Magnetic Resonance Imaging in Asymptomatic Uninjured Adults: a Systematic Review and Meta-Analysis
The British Journal of Sports Medicine, June 9th, 2018
Culvenor Et. Al
Institute of Anatomy, Paracelsus Medical University Salzburg & Nuremberg, Salzburg, Austria
Raise your hand if you hear a version this nocebo every day in the clinic:
“Yeah, I’m probably always gonna have knee pain… My doctor imaged my knees and said I got the knees of an 80-year-old.”
We love imaging so much in western medicine that we spend about $14 billion worth in it each year. Although imaging can give a fantastic insight into pathology, it doesn’t come without its own negative side effects. For example, studies have shown that early MRI in individuals with low back pain can lead to inferior outcomes, possibly due to the threatening language, negative self-perception, and nocebo that may come with it.
Inherently, you know positive signs on imaging of OA isn’t a death sentence for joints, but how can you effectively communicate that to your patients suffering in the midst of misinformation from uninformed practitioners? Thankfully, more and more data is becoming available that demonstrates the normalcy of positive imaging findings in healthy and asymptomatic individuals. The study presented here today from Culvenor Et. Al. looked at the prevalence and factors contributing to MRI features of osteoarthritis (OA) in asymptotic, uninjured knees.
How Often Do Signs of Osteoarthritis Appear on MRI in the Knees of Healthy, Non-Painful Individuals?
This systematic review examined the results from 63 studies that included 4,751 participants with a total of 5,397 healthy, non-painful knees. Based on MRI results, healthy, non-painful knees presented with the following odds of having the following osteoarthritic signs:
- Chance someone will have any osteoarthritic sign:
- <40 years old: 4-14%
- >40 years old: 19-43%
- Chance someone has an articular cartilage defect:
- 24% overall prevalence
- <40 y/o: 11%
- >40 y/o: 43%
- Chance increases 14.4% every ten years
- Chance someone has a meniscal tear:
- 10% overall prevalence
- <40 y/o: 4%
- >40 y/o: 19%
- Chance increases 3.2% every ten years
- Chance someone has a bone marrow lesion:
- 18% overall prevalence
- <40 y/o: 14%
- >40 y/o: 21%
- Note: Age is not as important as participating in weight-bearing sports. Individuals playing these sports have a prevalence of 30% compared to 3% playing sports! These lesions appear to be of more transient nature and can resolve without sequala
- Chance someone presents with osteophytes:
- 25% overall prevalence
- <40 y/o: 8%
- >40 y/o: 37%
- Chance increases 10% every ten years
Other things you may see in asymptomatic, osteoarthritic knees on MRI:
- No difference in findings between the tibiofemoral compartment compared the patellofemoral compartment
- Over the age of 40, arthritic findings are more common in the medial aspect of the joint at 14% compared to the lateral at 5%
- These numbers are good for storing in the back pocket when a patient says, “well my knees will hurt one day because of what I saw on my x-ray.” It may also be helpful for when they go in for something unrelated to arthritis, such as bumping their knee on the ground and then they get an x-ray at urgent care with the practitioner proclaiming they now have, “bad knees.”
- The understanding that osteoarthritis changes are a natural course of aging is important to help educate patients who may want to seek aggressive treatment for their knee, despite having minimal to no pain.
- The authors suggest centering your care more on symptoms rather than basing your treatment heavily upon imaging findings.
- Data from this study helps to explain why, at times, arthroscopic debridement may be no better than sham treatment that has been demonstrated in prior studies.
As we get older it’s normal to have some “osteoarthritic changes” that will pop up on MRI, even without pain or symptoms. This last part is the one most often omitted when patients receive their dire imaging-finding news. Although its true that severe osteoarthritic changes can lead to pain and even arthroplasty, it’s important to help educate patients on the possibility of having little to no pain or symptoms with OA, despite positive imaging findings in order to work towards positive change.
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