M having knee pain .twice got mri done .once the report revealed interstial acl tear and the other time mild synovial effusion .

I would treat you --: With pain meds and therapy. If no relief or improvement over a 10-12 weeks, then you might benefit from an arthroscopic examination, as some meniscal tears (8-10%) and most chondral lesions are not visible on mri's.

Arthroscopy: If you have exhausted all conservative treatments such as ice, anti-inflammatories, injections, and physical therapy, a diagnostic arthroscopy is indicated. You may have cartilage (articular or meniscal) damage in your knee and the acl should be evaluated. Check with your local knee doc.