Osteoarthritis (OA) - Knee

Osteoarthritis (OA) is the most common chronic condition of joints. It affects any joint. Knee is the most common (18%), followed by hip (8%). 


The most common symptoms of knee arthritis are : pain, stiff knee, joint swelling, limit ROM, and low deformity. These symptoms may not persist every day, and do not always progress steadily with time, and may be fluctuated with the weather condition. 


Obesity, trauma, lower limb alignment, bone mineral density, as well as gender are main factors that related to knee osteoarthritis. 


Although it occurs in people of all ages, it is most common in age older than 65. Hence, it is also called degenerative joint disease or degenerative arthritis.




Below is the picture showing the difference between a normal knee and osteoarthritis knee. The cartilage is already worn out, and bone on bone is the main reason causing the pain.


According to Center of Disease Control (US data), arthritis is more common among adults with age over 65. It is also more common among woman (24.3%) than man (18.7%).




Statistics further shows :

No. of American being diagnosed with arthritis - 50 million

No. of adults with osteoarthritis (OA) - 27 million

Percent of femage with arthritis - 25.9%

Percent of male with arthritis - 18.3% 



The estimated proportion of people in UK who have sought treatment for osteoarthritis, by gender and age group. 49% woman and 42% man whose age 75 or over has osteoarthritis.


The Kellgren & Lawrence system is method of classifying the severity of knee osteoarthritis. This is classified into five grades:

  • grade 0 - no radiographic features of OA are present
  • grade 1 - doubtful joint space narrowing (JSN) and possible osteophytic lipping
  • grade 2 - the presence of definite osteophytes and possible JSN on anteroposterior weight-bearing radiograph.
  • grade 3 - multiple osteophytes, definite JSN, sclerosis, possible bony deformity
  • grade 4 - large osteophytes, marked JSN, severe sclerosis and definitely bony deformity

There are different condition of leg (leg axis) and different pattern of foot print. Below shows the "bow leg", "straight leg" and "knock knees". Straight leg is normal. Majority is bow leg.

Below shows the different foot print. "B" type is normal while high arch is the majority.