Bad knees and running - good or bad?

I agree with the other two posters...but my sense is that it's probably not a great idea. I have some feet issues and was trying to be a runner for awhile and just jacking my feet up more...decided to be a cyclist instead and I enjoy it more to boot...though it is a bit more pricey to get into, but I'll have my bike for years to come so a great initial investment in my fitness.

Adding my agreement to the above as this is really a medical issue that needs to be addressed by the proper professionals due to your knee injuries. I would think that they would advise against it in favour of something like biking, swimming or rowing to avoid further damage.

definitely talk to a professional.
But with that, I have bad knees, I was diagnosed with the beginning stages of arthritis in my knees when I was 17, I was never into sports or fitness, Im now 30 and have been running for 10 months now (done 2 marathons, and training for a 3rd) and It has helped my knees so much. I have over done it and struggled to move for a day a couple times, but over all Ive seen a huge improvement.

I still cant ride a bike or workout bike without having issues moving the next day, I have an elliptical that has short bike like strides, and that kills my knees, (Im giving it away) but running doesn't seem to cause much of an issue, but thats just me

I agree about getting professional input, but generally studies have shown that running is actually good for your knees. I have bad knees from many years of hiking and backpacking with too much weight. Steep slopes get me every time. However I started running at 55 and six years later I'm training for my fourth marathon. When running, my knees don't bother me a bit, mostly because the hills I run are generally small (50-100' elev. gain) and not that steep. Flat roads and trails don't hurt at all.

my sports and knee dr has a very conservative rule for anyone over 40 years old even with good knees , he doesn't advise running and instead recommends anything with your foot on a pedal such as cycling or elliptical . Of course you use your own judgement and weigh it against your desire to jog or do whatever, but he makes everyone aware that after 40 jogging increases your risks for injury or damage to your joints .

I have the same issue and started running at 58 after I did enough strength training to build up the muscles around my knees....I am not the fastest but I do 5k, 10k and half marathon distances and my knees have never been better! No medication and finally off the Aleve I was always taking.

check out what the dr says but judge for yourself. While I was in recovery from meniscus tear surgery the surgeon told my wife that she should try to talk me in to only doing elliptical or bicycling. That was 2 years ago. After a recovery AND being told I have only ~50% cartilage in other knee, I am still running and doing squats and dead lifts again. I'm 58 years old. The point is there was and is pain but I am still out there 2-3 X per week trail running for an hour. No one has mentioned trail running yet. I converted over from road to trail after surgery and recovery. It IS easier on the knees and hips. Just take a golf ball and drop it on road surface then take it out on the ground. Which ball bounces higher? You'll enjoy the quiet and peace of the trail too. Again, listen to your body and dont sell yourself short for age or knee issues.