Arthritis is the breakdown of protective cartilage surface covering the ends of bones at a joint. When functioning appropriately, this cartilage surface allows smooth and painless motion at the joints. However, as the cartilage wears out over time or after injury, the contact of the exposed ends of bones causes pain, swelling, and stiffness. Arthritis symptoms generally progress over time at an unpredictable rate (months, years, decades) and can have periods of decreased or increased pain and symptoms. Arthritis should initially be treated conservatively with physical therapy, injections, medications, and activity modifications. A partial knee replacement (unicompartmental) is used as an alternative to a total knee replacement when the damage from arthritis is limited to only one portion of the knee, reasonable conservative treatment has been exhausted, and pain continues to significantly affect quality of life.
