What does partial chondroplasty on the medial facet of the patella mean? Also why does it show a slight tilt of the patella on an x ray?

Osteoarthritis. You have osteoarthritis of the patella which means you have lost some of the thickness of the articular cartilage which is like losing some of the "rind on an orange". Tilting of the patella could be a result of the loss of the cartilage from arthriitis.
Chondroplasty. A chondroplasty means the cartilage is being smoothed out, and loose or unstable parts are removed. The patella is the kneecap, and the medial side is the inner side. In short, the answer is the cartilage of the inner side of the kneecap was smoothed out. Tilting of the kneecap can occur for a number of reasons. Treatment most often is done with therapy, but surgery may be an option.