PARIS – Knee trauma from a childhood sports injury can have serious consequences in young adults, judging from preliminary results from a historical cohort.
When assessed 3-10 years after the sports injury, at an average age of 22 years, young adults appear to be at higher risk of abnormalities visible on MRI that are consistent with future arthropathy and have poorer knee-related quality of life and more knee symptoms.
They are at higher risk of having structural asymmetry of the vastus medialis muscle and being categorized as being overweight or obese.
There also appears to be some trends for increased percent body fat and reduced participation in physical activity, Jackie L. Whittaker, Ph.D., said at the World Congress on Osteoarthritis.
She stressed that these are preliminary findings and that the group hopes to quadruple the size of the cohort this year in order to better understand the relationships they’ve identified.
"With that being said, if we are seeing what we think we’re seeing, there may be some clinical, structural, physiologic, and behavioral markers that can be used to identify individuals who are at risk and target them with secondary prevention strategies at an earlier age," said Dr. Whittaker, a postdoctoral fellow and physiotherapist, University of Calgary Sport Injury Prevention Research Centre, Alberta, Canada.
The historical cohort study involved 25 patients recruited from previous sports injury epidemiology studies who had an intra-articular knee injury in ice hockey (male and female), soccer, basketball, or other sports that required medical attention and time off play, and 25 uninjured controls matched on age, sex, and sport. The median age at injury was 15 years (range 9-18 years). Eight patients in the injured group had contralateral knee surgeries, in addition to surgery on the primary knee. The median age in both groups was 22 years.
Using the Knee injury and Osteoarthritis Outcome Scores (KOOS) outcome, injured participants scored significantly lower, indicating worse function, on all five, 100-point subscales: pain (mean 93 vs. 97), symptoms (mean 82.9 vs. 92.4), activities of daily living (mean 96.3 vs. 99.3), sport/recreation (mean 90.6 vs. 97.4), and knee-related quality of life (mean 89.7 vs. 97.7), Dr. Whittaker said.
Further, in a subsample of 10 matched pairs, injured participants were three times more likely to have an MRI Osteoarthritis Score (MOAKS) of one than were matched controls, according to the study, led by her colleague Carolyn Emery, Ph.D.
Although there was no difference in quadriceps strength between groups, injured participants were 3.8 times more likely to have a difference in the cross-sectional area of the vastus medialis muscle greater than 15%.
"We think that this may be clinically relevant, as there has been some recent prospective work (Arthritis Rheum. 2012;64:3917-25) that has shown a temporal relationship between a decrease in size of the vastus medialis muscle and progression or loss of tibial joint cartilage," she said.
Within 3-10 years after their knee trauma, injured participants have a significantly higher mean body mass index (BMI) than do uninjured participants (25.4 kg/m2 vs. 23.2 kg/m2) and a trend for more body fat (20.8% vs. 18.7%).
Not surprisingly, these troubling findings were coupled with a trend for injured participants to spend less time each week participating in moderate to strenuous activity (97.8 minutes vs. 101.4 minutes) and also fewer participated in sports in the previous year (4% vs. 16%).
"If we dichotomize BMI, what we see is that those individuals in the injured group are two times more likely to have a BMI that is [classified as] overweight or obese," Dr. Whittaker said at the meeting, sponsored by the Osteoarthritis Research Society International.
During a discussion of the results, the suggestion was made to stratify future data by age at injury, as puberty has an influence on response to injury.
Dr. Whittaker reported funding from the Alberta Children’s Hospital Foundation, Alberta Innovates Health Solutions Alberta Team Osteoarthritis, Canadian Institutes of Health Research, and the University of Calgary Sport Injury Prevention Research Centre.