Objectives To evaluate the short-term impact of longdistance running on knee joints using MRI.
Methods 82 healthy adults participating in their first
marathon underwent 3T (Tesla) MRI of both knees 6
months before and half a month after the marathon: 71
completed both the 4 month-long standardised training
programme and the marathon; and 11 dropped-out
during training and did not run the marathon. Two senior
musculoskeletal radiologists graded the internal knee
structures using validated scoring systems. Participants
completed Knee Injury and Osteoarthritis Outcome Score
questionnaires at each visit for self-reporting knee
function.
Results Premarathon and pretraining MRI showed signs
of damage, without symptoms, to several knee structures
in the majority of the 82 middle-aged volunteers. However,
after the marathon, MRI showed a reduction in the
radiological score of damage in: subchondral bone marrow
oedema in the condyles of the tibia (p=0.011) and femur
(p=0.082). MRI did also show an increase in radiological
scores to the following structures: cartilage of the lateral
patella (p=0.0005); semimembranosus tendon (p=0.016);
iliotibial band (p<0.0001) and the prepatellar bursa
(p=0.016).
Conclusion Improvement to damaged subchondral bone
of the tibial and femoral condyles was found following
the marathon in novice runners, as well as worsening of
the patella cartilage although asymptomatic. This is the
most robust evidence to link marathon running with knee
joint health and provides important information for those
seeking to understand the link between long distance
running and osteoarthritis of the main weight-bearing
areas of the knee