Mri diagnosis of horizontal undersurface tear posterior horn medial meniscus and grade ii chondromalacia patella with trace knee effusion . surgery?

Obviously you have -: -symptoms, so if the trouble is locking, giving way, the findings indicate a mechanical problem in the knee. You need to follow the advice of your orthopedic surgeon who is familiar with your case, especially if you have treated with him/her for a while. The surgery is only driven by your symptoms. The thing to remember is there is no orth prob so severe that it can't be made worse by surgery.