Morning stiffness of the knee joint may be described as rigidity in the knee joint after waking up in the morning or after a resting period. It may be severe but is usually brief for less than 30 minutes.
The most common cause of morning stiffness of the knee joint is rheumatoid arthritis or osteoarthritis. Both these disorders causes inflammation and stiffness but RA is more specifically related to morning stiffness.
Although it is hard to describe morning stiffness but patient generally complains of an ache in the knee joint combined with difficulty moving.