Replying to Knees after acl reconstruction..scar tissue?

ive been out of surgery for a little over a year now, aand starting about 2 weeks ago ive been randomly getting this ridiculously sharp pains in the knee i had surgery on when i walk..ive heard a few people say it was scar tissue breaking up..has this happened to anyone else? does anyone know how long this is going to go on for? it happens randomly to me but its been happening more frequently and it killllls..
oh, and i partially tore my meniscus when i tore my acl, and they tried to repair it but they dont know for sure if it worked..could it be that?
thanks