After having knee replacement, sexual relations can be resumed when you have healed and feel more comfortable, usually around 4 to 6 weeks after surgery. Check with your surgeon if you are unsure when to safely resume sexual activity.
It will take a few weeks for your knee to heal and get moving again. You may have swelling and experience fatigue. You will most likely require pain medications during this time period.
Waiting to resume sexual activity until you feel more like yourself will result in more pleasant relations. It will also give your knee the opportunity to heal successfully.
Avoid kneeling positions initially. Eventually, when you are completely healed, most surgeons allow you to kneel. Check with your surgeon to make sure this is the case. At first, you should assume a passive role, using positions that are comfortable for your knee. Pillows can be used to support your knee. You might find pain medications, either narcotic or over-the-counter, helpful to keep you comfortable. Plan sexual relations for a time when you are well rested.