The authors report their experience in the arthroscopic treatment of joint-related stiffness of the knee. Arthroscopic arthrolysis is the treatment of choice for numerous conditions (stiffness subsequent to inflammatory processes, stiffness associated with marked osteoporosis, etc.) in which open arthrolysis is contraindicated. The totally atraumatic nature of arthroscopy and the more accurate lysis of the adhesions allow for postoperative management without complications or pain. This is of particular importance as it permits passive and active kinesitherapy from the moment the patient recovers from anaesthesia, without pain and therefore with greater commitment on his part. Furthermore, arthroscopic arthrolysis can be used successfully to treat extensor muscle stiffness where endoscopic study has revealed the presence of adhesions or calcification in the anterior compartments.