Knee arthroscopy (keyhole surgery) involves 2 small incisions (less than 0.5cm) either side of the kneecap. One of these incisions is for the camera, one is for the instruments. Occasionally a 3rd incision of similar size is required depending on what procedure is being performed.
The procedure is usually carried out under general anaesthetic. It is a day case procedure so you should be home the same day. Most patients go home walking without crutches but certain procedures may require these. (You shall be told of this pre-operatively if appropriate.)