How common is knee damage among middle-aged non-runners?
Published February 2020 in Skeletal Radiology
This knee study looked at non-runners with no apparent symptoms of knee damage. We found evidence of knee abnormalities in more than 97% of the group. Knee damage can therefore be considered a normal finding in MRI scans for mid lifers — and should not prevent you from starting or returning to running.
It’s well known that issues of the knee joint increase with age, and may already exist before middle age with no symptoms. In fact, both well- and poorly-functioning knees can have similar damage - and it can be difficult to correlate relevant MRI findings with patients’ knee pain.].
The purpose of this study was to determine the prevalence of abnormal knee findings in asymptomatic adults by means of MRI. This is the largest study to date using this high-resolution technology to provide a robust analysis of all knee structures.
In short…
The study
Our objective was to assess knee health in non-running adults
We recruited 115 adults with no symptoms of knee damage, comprising 51 males and 64 females aged 25-73.
25 volunteers were under 40, while 90 were aged 40+.
Volunteers were chosen because they were largely sedentary. They did not meet the health recommendations of 30 minutes’ moderate exercise, 5 times per week, or 20 minutes intense exercise on 3 days of the week.
Participants completed a ‘Knee Injury and Osteparthritis Outcome Score’ to ensure they were asymptomatic.
Each volunteer underwent bilateral knee MRI scans.
What we found
97% of all knees showed abnormalities in at least one structure within the knee joint.
Typical findings were meniscal tears (30% of knees), cartilage abnormalities (62%), bone marrow oedema (52%) and abnormalities within tendons (46%) and ligaments (38%).
The prevalence of lesions generally increased with age and was not linked to Body Mass Index (BMI).
What it means
The study raises questions around how efficient arthroscopy (a surgical procedure where a small camera guides a surgeon to repair or reconstruct the mknee) is in reducing symptoms and treatment. The high rate of asymptomatic adults with knee joint abnormalities on MRI may indicate why arthroscopy and other surgical interventions do not always result in good outcomes.
For example, there is no evidence to suggest that meniscectomy benefits patients presenting with meniscal tear symptoms. Moreover, some surgical interventions could lead to further complications or deterioration of the cartilage and increase the risk of osteoarthritis.
Despite the increasing use of high-resolution MRI, in practice, diagnosis should be primarily based on patient’s medical history and physical examination by an experienced clinician. MRI images may assist in correlating clinical signs and symptoms but should not replace clinical evaluation.
