Table 2 Proportion (%) of people with radiographic knee OA in populations with knee pain according to the definition of knee pain.

Hannan [25]

Pain, swelling, morning stiffness in or around the knee on most days for one month

Positive response to both parts required:

Lanyon [8]

(A) Have you ever had pain in or around the knee on most days for one month?

McAlindon [15]

McAlindon [17]

Lethbridge [10]

(B) If so, have you experienced pain in the last year?

Felson [20] (Part A only)

Cicuttinni [11]

Ever having an episode of knee pain

Cicuttinni [26]

Ever having an episode of knee pain lasting more than 15 days

Peterson [19]

Pain in your knees practically daily for the last 3 months

Lachance [13]

Any joint pain in their knees during the last during the last month

Hart [18]

Pain, stiffness and swelling lasting more than a month

Odding [14]

Knee pain during the past month

Jordan [35]

Knee pain on most days

Davis [27]

Knee pain on most days lasting for one month in the past year

Williams [21]

Brandt [24]

Ang [23]