My 86 yr old grandma was at my aunt's house this weekend, and came home unable to stand without knee pain. The pain is only on her right knee, which is red, a little swollen, and tender to the touch. Her left knee is completely fine. She cannot stand at all without help.

She does not remember much of anything anymore and can't recall if she fell or if something happened. My aunt says that she called the doctor and described her symptoms, and he diagnosed her with arthritis without seeing her knee. We don't think it's arthritis because she's never had arthritis and in the years she's lived with us, she's never had this happen.

Is it possible she tripped and fell and my aunt isn't telling us? We're going to bring her to the doctor in the morning to find out if it's really arthritis.

PS- if it helps, she has gout problems but it only happens to her feet, and her feet are fine today.