This article is from The Arthritis Foundation:

There’s no question that indoor cycling is an excellent way to get a cardiovascular workout without stressing weight-bearing joints, says Matthew Goodemote, head physical therapist at Community Physical Therapy & Wellness in Gloversville, N.Y. It’s also a good option for people with balance problems, he adds, because there is no need to lean the bike to turn. “People with osteoarthritis (OA) or rheumatoid arthritis (RA) who become inactive because of pain often develop balance problems, so they are less likely to injure themselves on a stationary bike,” he says.

Want to start a routine? Go for it, but start slowly, perhaps with a five-minute session at a comfortable pace three times per day, says Goodemote. “Once people can ride with no pain for five minutes three times a day, I bump them up to seven minutes, then to 10, 15 or 20 three times per day – getting them to 30, 45 or 60 minutes of exercise per day. Initially, adding five minutes seems like a big jump, but once tolerance builds, larger gains are made in shorter time frames. Down the road, people can more easily add 15-minute increments to their rides.

Right now I am back in Physical Therapy for my knee (again!) That auto accident  two years ago didn’t do anything to help the knee. I had already had a number of sports injuries over the years. Right now I am experiencing pain on the outside of the knee at the site of the ligaments. I never tore anything, just pulled everything pretty badly. The therapist gave me a thing like a big rubber band. It is a rubber ‘ring’ and I step into it and can sit in front of the TV and pull my knees apart in repetitions. She has me going up and down on my toes and then standing on one foot for a minute at a time. These are all exercises to build up the muscles on the outside of the leg and work to stabilize the knee. I am still riding my bike everyday at least 2 miles and usually 5 miles. The doctor had me increase the Ibuprofen to 3 in the morning and 3 at night. Also, I am supposed to ice the knee after every work out to reduce the swelling.

What I have is a little swollen patch on the bottom of the knee where fluid collects and then this off and on pain on the outside of the knee. The swelling does seem to have gone down. The icing seems like it is time consuming but, whatever! More and more articles on the Internet are stressing bicycling as great low impact exercise and a way to save the joints from osteoarthritis and then joint replacement. Whee! My mother had both knees replaces and it was zero fun. So, helmets on!