A knee is divided into three separate compartments. One involves the front of the knee (patellar femoral compartment), a second the inside of the knee (medial compartment) and the third the outside of the knee (lateral compartment). In some cases, only part of a knee is worn out and a person does not need the entire knee replaced to relieve pain.
Patients with partial knee replacement surgery usually recover quicker than those with total knee replacement surgery.
The pictures show a Biomet Oxford Partial Knee Replacement and a Vanguard Total Knee Replacement. The patella is not shown on these images.