What happens to marathon runners’ knees in the long term?
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Published February 2020 in Skeletal Radiology
Our third study focused on the results of a medical assessment made on the 2018 London Marathon runners six months after the event. We found that knee health (especially bone marrow and cartilage) continues to improve after a marathon, suggesting that running may help reduce the chance of osteoarthritis in the long term.
Previous studies had only examined knees of regular long-distance runners soon after their marathon. No significant pre-existing injuries had been reported in the first place for this research. Limited peer-reviewed data on the impact of marathon running showed that post-marathon joint alterations return to baseline within three months.
But studies up to this point were conducted with a very small population of regular long-distance runners (up to 13 participants; with one knee scanned only) and none studied running-related lesions over time in runners participating in their first marathon.
To better understand the implications of long-distance running for the knees of novice runners, we set out to evaluate changes in the knee joints of first-time marathon runners six months after the run itself.
In short…
The study
Our objective was to assess knee health in runners six months after their first marathon.
We only included participants from the previous study (Study 1). 44 of the previous 82 participants returned for this study.
The 44 participants were assessed at three time points - 6 months before the marathon (MRI 1), two weeks after the event (MRI 2) and approximately 6 months later (MRI 3).
Both knees were scanned and analysed independently.
Volunteers were asked to complete a questionnaire to assess how they perceived the condition of their knees.
What we found
Six months post marathon, two runners showed improvement in the patellofemoral compartment of their knees: pre-marathon lesions which were unchanged from MRI 1 to MRI 2 showed improvement at MRI 3.
Three cases of bone marrow oedema had improved at MRI 2 and this was sustained at MRI 3.
No participants had any new lesions at the 6 month follow up scan.
14% of cartilage lesions reversed over time, returning to base level.
56% of bone marrow lesions improved over time, with 8 returning to the pre-marathon state.
There was no significant differences between marathon finishers and pre-race dropouts - suggesting that the training is as beneficial as the event itself.
What it means
Our study suggests that marathon training may be linked with imrpovement to knee joint health in novice runners.
This is the first study to show the beneficial effects of marathon running 6 months after the event.
The sustained benefits to the knee suggests that running may help to reduce the chance of osteoarthritis in the long term.
