Tiny plugs of healthful cartilage from non-weightbearing parts of a joint, including the side in the knee, are taken out and made use of to exchange tiny parts of damaged knee articular cartilage. It is frequently caused by overuse or misalignment of the knee joint. Knee Bursitis - Knee bursitis https://www.theorthopaedicandpainpractice.com/chondromalacia/