You can usually expect huge improvements in pain and mobility after knee replacement. Most surgeons recommend you stay away from high-impact exercises like jogging or jumping rope, even if you did them before. Ask what other sports may be off-limits for you, too.
You’ll still have lots of ways to stay active. You can walk, swim, bike, do light hikes, and play doubles tennis. Weight training will give you stronger muscles and bones. Be sure to ramp up by doing more reps instead of adding heavier weights.