I am a firm believer in exercising to maintain health of mind, body and spirit. After consulting with your doctor--especially if you have joint issues, start out slow and listen to your body. You will know if you pushed yourself too hard as it may take days to recover.
Walking and swimming are excellent. Walking inside a mall is great for the winter months and some malls have "walkers groups" that meet daily or weekly to trek through the malls early in the morning for exercise.
Not all of us have access to an indoor pool but if you do you may want to consider gentle swimming or exercising in the pool. The heated pools are the best of course
If you have an exercise bike or treadmill at home take it very slow in the beginning and determine how you feel afterward as well as the next day or two. Do you feel better or worse?
Hope you find a suitable activity that helps with your healing. For me some sort of exercise has always been important as it also helps to chase the blues away.