Treatment for radial & longitudinal tears of the posterior horn medial meniscus, severe knee osteoarthrits moderate joint effusion, diffuse synovitis?

Numerous . The most definitive option is a knee replacement. Knee arthroscopy is not likely to be helpful at this point. Various injections such as cortisone, hyaluronic acid/joint fluid or platelet-rich plasma are reasonable options. Meds, braces and PT are considerations. If I can help, then join my care team and virtual practice at www.healthtap.com/dr-clarkeholmes.