Thank you, it's wonderful to be here, and I'd like to acknowledge my co-author on this paper too, Julian Feller. It's well established that younger age is a risk factor for sustaining multiple ACL injuries. It's estimated that young athletes have two to five times a greater risk for either a graft rupture or a contralateral ACL injury compared to their older age counterparts. Now if we look at young athletes over a longer period of time, the picture becomes pretty bleak. A study by Salmon and colleagues out of Sydney, Australia reported that just 46% of grafts survived in males and 69% in female athletes at a follow-up of 20 years. There weren't relatively many young adolescent athletes in this study, and overall there are few studies in adolescents with longer-term follow-ups. Therefore the purpose of this study was to report rates of graft and contralateral ACL rupture after ACL reconstruction in a large series of younger patients over a period of up to eight years following a first-time ACL reconstruction. This was a single-surgeon series of 400 consecutive patients who were under 18 years of age and undergoing primary ACL reconstruction. Those with a prior contralateral ACL injury and bilateral ruptures were excluded, as were two patients who died within six months of having their surgery. So the primary outcome was second ACL injuries, and this was either a graft rupture or a contralateral ACL injury. And we followed up all patients to document further ACL injuries by first reviewing all medical records, then conducting electronic surveys and telephone interviews with structured questions. The last follow-up date was either the date of the patient's last clinic review or the date they completed their survey or telephone interview, whichever was latest. And we conducted a Kaplan-Meier survival analysis. We also used long-term tests to look at differences in the survival functions between our male and female athletes. So this shows the cohort demographics. We had an overall final cohort of 388 athletes, with a fairly even distribution between male and female athletes. And as you can see, most patients had a hamstring tendon graft. We had an average follow-up of five years. Fifty per cent of the cohort will follow up between five and eight years, and for 87 per cent of athletes, they had a minimum three-year follow-up. So if we first look at graft rupture, and if we look at the overall rupture rates via survival analysis, they were 11 per cent at two years, 16 per cent at four years, and 29 per cent at eight years. And overall, the rates of graft rupture were higher for our male athletes compared to females. However, this was a lot more noticeable at the four-year follow-up, and much more reduced at the eight-year time point. If we now look at contralateral ACL injury, the survival rates were at eight per cent for two years, 17 per cent at four years, and 50 per cent at eight years. There were no statistically significant differences in the survival functions between our male and female athletes, and the males here are shown in green and the females are in orange. But what you might notice is, over the first five years, four to five years, females did have a higher rate of contralateral ACL injuries. But after five years, the rate in males significantly increased, such that they were 64 per cent compared to 36 per cent at eight years. So in summary, this study clearly highlights the high risk for second ACL injury in our younger athletes. The studies are fairly consistent with a recent study by DiFrancesco et al, who looked at a large cohort of under 16-year-olds and reported a 21.6 per cent cumulative graft rupture rate by four years. And clearly, in our study, over time, the cumulative risk for contralateral ACL injury was greater than for graft rupture. And this was probably because we saw this surge of contralateral injuries in our male patients after five years. And this is a new finding, and we probably saw it because we had a large cohort that we followed over a significant period of time. The implications of this finding is that we really need to educate our young athletes, and predominantly our male athletes, of this risk once they resume and continue to participate in sports that pose a high risk for knee injuries. Thank you.

second ACL injuries

younger athletes

risk factors

graft rupture

contralateral ACL injury