Going ahead with ACL reconstruction depends not on MRI scan but what your symptoms are. Do you have instability of knee, does your knee give way or do you stop yourself from playing sports due to knee stability issues? Also some times depending on your requirements an intensive physiotherapy program can give you the desired stability of the knee. Discuss all these options with your Surgeon or seek opinions before committing to surgery. The treatment is for the patient not for the scan. Hope this helps.