Always consult with your physician before exercising post-surgery, injury, or extended hiatus. That said, I often have patients who wonder how to have effective workouts even with sensitive joints, muscles, or pains. First and foremost, find something that is enjoyable for you and ease into a routine. The following are exercises that are low impact on muscles and joints but are extremely effective cardio. My patients have seen both fat loss and muscle growth with these types of exercises.
Swimming
Bodyweight Training
Walking
Yoga
Rowing
TRX
Elliptical
Rope
Kettlebell