Inservice- out of service

Today, my son had an in-service day and we went to the soft play. We were there and having a great time using this slide. A few goes later and I accidently stood on his hand. A few after that and as we got up to get out, my knee went pop and I dropped him on his head!! He was fine in a few minutes. Not sure what damage I have done to my knee, it's the one that has had a full ACL reconstruction, ouch.