Arthritis is a destructive process involving the cartilagenous joint lining (the 'gristle') at the end of the bones.
Causes of arthritis in the knee
There are many causes and types of arthritis, but the one which is most common and also most commonly associated with knees is 'osteoarthritis'
Management of knee arthritis
Doctors tend to take different approaches in the management of osteoarthritis depending on their particular line of interest - a general practitioner may tend to look at general factors such as weight and diet, a rheumatologist may prescribe anti-inflammatories, including steroids, and knee surgeons tend to take a mechanical approach and try and sort out any structural problems.