Can i exercise with avn in my hip and knees?

Yes: Avascular necrosis (avn) is more common in the hip than the knee, and results from impaired blood flow to a region leading to bony death. It will extremely painful to move the affected joint, however the exercises that would benefit you would be open-chain exercises (non weight-bearing).

Yes to tolerance: Avn can be asymptomatic but can be quite painful in the groin and knee with weight bearing and activity. Lower impact exercise is recommended. Bicycle, swimming, isometric exercises. Depending on the stage of avn, there are several options. The earlier stages have more options. The later stages require joint replacement surgery. Make sure you have regular follow up with your orthopaedic surgeon.