• Young athletes with knee injuries had similar changes in body fat mass vs. uninjured athletes.
• The post injury period may be a potential window for obesity prevention.

Young athletes with knee injuries demonstrated similar adiposity gains vs. uninjured athletes at 2 years post-injury, revealing a potential window for obesity prevention strategies, according to a study in Arthritis Care & Research.

“Knee joint injuries and elevated adiposity are independent risk factors for knee osteoarthritis (OA),” Justin M. Losciale, DPT, PhD, of the George E. Wahlen Department of Veterans Affairs Medical Center in Salt Lake City, and colleagues wrote. “Evidence also indicates that youth and young adults who experience a knee injury have higher body and fat mass 3 to 10 years after injury, and are less active at 3 to 12 years compared with uninjured peers. Taken together, these findings suggest that a knee injury may initiate a cycle of inactivity and sedentary behaviors, leading to adiposity gains that compound the risk for post-traumatic OA (PTOA).”

In a prospective cohort study, Losciale and colleagues aimed to compare fat mass changes between juveniles with sports-related injury vs. those without injury over a period of 2 years. In all, they analyzed changes in total body fat mass among 186 young athletes (mean age, 16 years) from the Alberta Youth Prevention of Early Osteoarthritis Cohort.

Among the included athletes, 106 had a sport-related knee injury, while 80 were uninjured. Of the 106 injured athletes, 60 demonstrated an ACL injury. Outcomes were assessed at baseline, 6-, 12-, 18- and 24-month follow-up.

According to the researchers, the estimated average difference in fat mass gain for injured vs. uninjured athletes was 0.1 kg at final follow-up. Similarly, there was no significant difference in total fat mass between injured vs. uninjured athletes at 6 months (0.9 kg), 12 months (0.7 kg), 18 months (0.1 kg) or 24 months (–0.9 kg). In addition, the researchers found no difference in fat mass gain or total fat mass among athletes with ACL injury vs. without ACL injury, or female vs. male athletes.

“These results suggest that we cannot rule out that adiposity gains over the time period are possibly due to maturation, not necessarily a result of the knee injury,” Losciale and colleagues wrote. “Adiposity gains over the time period may not be linear and may not differ by injury type (ACL tear or other injury type) or participant sex.

“Given previous evidence showing higher adiposity beyond 3 years after injury, our findings highlight a potential window for prevention interventions,” they added.