Partial knee replacement

The knee is divided into three compartments. A medial (inside), lateral (outside) and patellofemoral (kneecap) compartment. There are individuals that develop arthritis in only one of the three compartments of the knee joint. 
If the rest of the knee is in good condition with intact ligaments then it is preferable to replace only the worn part of the knee and leave the good parts alone. This gives a more natural feeling to the knee after replacement often with a near full range of movement.
If you are experiencing knee problems then this score can be used to determine how much they are affecting your quality of life.