I am not familiar with what happened to you, but I had acl surgery a little over 3 months ago, and soon after I realized that I didn't have full extension (couldn't straighten my leg) and little flexion (bending). I went to my doctor and he said Iahd arthrofibrosis which is scar tissue build up. This is what preventing all of this. Maybe this is what you have?? I don't know but maybe you could ask your doctor about this. I hope this help a little..
shannon