Why do my knees hurt in the morning?

Pain and stiffness are related. Often after a long rest or prolonged sitting, people had difficulty moving about. Stiffness is often caused by a little swelling in mildly inflamed regions of the knee, usually as a result of a small degree of osteoarthritis. It generally wears off quickly as we move around. About half of the 4,000 people in the NDB with hip or knee osteoarthritis have stiffness that lasts 30 minutes or less. In the Table below, the relation between stiffness and pain is shown. Pain is measured on a 0-10 scale, with higher values representing more pain.

AM Stiffness | mean
-----------------+----------
No am stiffness | 2.25
Less than 30 | 3.24
30 minutes to 1 | 4.86
1-2 hr | 5.80
2-4 hr | 6.68
4-8 hr | 7.02
>8 hr | 7.07
-----------------+----------
Total | 4.53
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Fred Wolfe, MD