The advantage over traditional open surgery is that the joint does not have to be opened up fully. For knee arthroscopy only two small incisions are made, one for the arthroscope and one for the surgical instruments to be used in the knee cavity. This reduces recovery time and may increase the rate of success due to less trauma to the connective tissue. It has gained popularity due to evidence of faster recovery times with less scarring, because of the smaller incisions. Irrigation fluid (most commonly 'normal' saline) is used to distend the joint and make a surgical space.