Debunking Common Myths About Running and Knee Osteoarthritis

A recent BJSM article reminded me of a patient I saw a few weeks ago. He came in for shoulder pain, and we got to talking about his running habit of around 200 km a month, along with occasional crackling in his knees. He originally assumed it was mild knee wear, but the X-rays of both knees showed the right knee had already progressed to grade 2 on the Kellgren-Lawrence grading scale, and the left to about grade 2-3, more advanced than I had expected.

This myth-busting article raises several key points:

1. There is no clear evidence that a recreational running habit causes knee osteoarthritis.

2. Compared with people who generally do not exercise, recreational runners have a lower rate of knee osteoarthritis (3.5% versus 10.2%). For the lower-limb joints, a recreational running habit may have a protective effect, whereas elite competitive runners have a higher likelihood of knee osteoarthritis (13.3%).

3. The factors associated with knee osteoarthritis are still not clearly defined.

4. For runners who already have knee osteoarthritis, continuing to run should be safe and beneficial, though moderately reducing frequency to give the knee cartilage enough time to recover can be considered.

5. Research supports that running does not worsen osteoarthritis in older runners (over 50).

6. For runners with osteoarthritis, cutting back on running just to control symptoms is not a wise recommendation.

Many past studies have also supported that a recreational running habit can improve cardiorespiratory fitness, bone density, chronic disease control, and other health benefits, without increasing the risk of osteoarthritis. Similar studies are often criticized because the running volume or the definitions of recreational and elite runners are not accurate or consistent enough, and most designs cannot achieve randomized controlled trials. There is also no dose-response study on running with a clear conclusion yet. As more research is invested, the results should become increasingly clear.

Coming back to this patient with no obvious symptoms, I recommended that he keep running while paying attention to whether his osteoarthritis symptoms change. He can also add some lower-limb resistance training to keep strengthening his lower-limb muscles.

References

• Infographic. Running Myth: recreational running causes knee osteoarthritis. Br J Sports Med. 2022 Mar;56(6):357-358.
• Running causes knee osteoarthritis: myth or misunderstanding. Br J Sports Med. 2018 Feb;52(3):142.
• Automatic Detection of Knee Joints and Quantification of Knee Osteoarthritis Severity Using Convolutional Neural Networks. July 2017

Further reading

• Knee topic
• Runner topic
• Sports injury overview
• PRP prolotherapy
• Rehab exercise prescription
• Pain management