Hello, everyone, i do the acl restruction operation in my left leg more than one year, but i still hurt in front end on my knee when i bend knee?

Patella femoral : If your pain is in front/under your knee cap, then most likely patella femoral pain syndrome/chondromalacia patella. Best managed with exercise to strengthen your quads to improve tracking, and avoiding deep knee bending activities. Also oral or topical nsaids can be of benefit, as well as a brace. Injection of cortisone or hyaluronic acid also very popular. If all else fails, then scope.