Exercise Suggestions -- Bad Knee Problem

I know exactly how you feel...
I've had my left knee surgically repaired 4 separate times, the last time I had some screws removed that had been in place 16 years. The source of the pain turned out to be mostly the screws, doctors are not carpenters and they don't understand the obvious sometimes! When you have screws that stick out the back side of the bone approx. 3/4" it's bound to be an issue eventually. My advice is to have the hardware removed as soon as it's possible.
I would say that as far as exercise is concerned try a variety of things and see what feels the best for you, I'm dealing with a whole new round of knee issues right now and a bicycle works best for me, once I make my final trip to see my Dr. and I'm released I'm going to spend more time on the elliptical, unfortunately I don't have access to a pool for quite a while so I'll do the best I can.

This is just a thought for you but after my last operation on my knee I did go to a treadmill starting the next day. It Really helped out. Before you roll your eyes and hit the delete I want to be specific about what I am saying. Many PT clinics now have tread mill that have weight bearing systems. These are made for people with an injury or are very over weight. They are like a balloon and help lift you up so you can carry your weight. The system works wonders and you can even run on it at full speed. The first time I did it I thought it was nuts. After 15 minutes I was soaked with sweat. It works. Look for this type of system. You will be glad you did.

I had TPF with hardware (12 screws and plate put in one year ago today) The best thing that I did for my leg was a spin class and water work. If you do the spin class just modify it for your leg. I never stood when the rest to the class did, I just stayed seated and adjusted my resistance. Any type of pool work is excellent. You are taking the weight off the leg, but building the muscle in the leg. I hope all goes well.

+1 on the pool. Have bad OA in my left knee and completely root torn meniscus in my right knee....started swimming two and a half years ago combined with forward and backward lunges and it's helped a lot in conjunction with logging my caloric intake on MFP here. Having the buoyancy of the water negates the direct pressure of all one's weight on those sore joints and allows you to stretch and strengthen those tender ligaments and muscle areas. Losing a pound of weight equals 6 pounds less stress, so weight loss has helped me significantly. Good luck!

My TPF happened in March 2011. Plate and screws were added. I also have a bunch of other ills. My age (over 75) doesn't help matters. I have tried to do "perfect" walking, starting with a couple of steps per day. I won't walk with a limp. Now, I average 6 miles per day with a pretty good pace. I love the hills the most. Fitbit rules the day!
Gains happened little by little, but never forcing myself to walk if it couldn't be "perfect" balance, stride, heel strike etc.
Good luck and keep at it.