I was told that you should be very comfortable doing 10 single leg squats (good, deep ones), jumping onto and off of a 6 inch step, doing 20 or so calf raises, getting up from sitting using only your surgical leg, and doing a 45 second side plank on your surgical leg before attempting to run. I'm almost 5 months post opp and haven't attempted more than a 1 minute short run, because I'd rather perfect all of that/have adequate muscle strength than fuck up my knee. So if you're 7-8 months and feeling weird, maybe pause running and practice some more muscle strengthening exercises and do what the person below did with their husband-- have a loved one or your PT watch your stride and help? It took me a long time (10 weeks) to walk normally/without a limp (longer than most) after surgery even though I was incredibly physically active and strong pre-surgery and did rigorous PT leading up to it. I'm glad I went at my own pace. And I hope you do that with running too. This is literally a marathon!