Patient has arthritis in the knew is ice good for knee. what about exercise? she is not able to lift leg and walk.

Yes ice can and does: Help a lot of pts. Exercises are vitally important to regain strength and range of motion, which also decreases the pain. Once she does regular exercises she should be able to walk and lift her leg, providing no severe back or hip problems are also present. See a local orthopod who can treat you. Pt, heat pads (as some people find them better than ice) would be helpful. Surgery is an option also.

See details: If the arthritis is severe the only option may be joint replacement assuming the person is medically cleared for surgery. Other options include meds and injectable lubricants. Have the knee evaluated to better understand the options.