Suggest Treatment For Tricompartmental Chondromalacia

I had knee surgery 4 years ago, I just had an MRI and it is showing Tricompartmental chondromalacia, most severe in the medial compartment with areas of fujll thickness chondral loss and cortical remodeling. There is an extensive tear of the posterior horn and body of the medial meniscus which is diminutive in size. Horizontal tear of the posterior horn of the lateral meniscus. There is also a popliteal cyst. 4 years ago I had 80 percent of medial meniscus removed and 40 percent of lateral meniscus. I am 60 years of age - what is the treatment.