Arthroscopic: Refers to a surgical technique whereby a doctor inserts a tube-like instrument into a joint to inspect, diagnose and repair tissues. It is most commonly performed in patients with diseases of the knees or shoulders. The word arthroscopic is often confused with orthoscopic. Orthoscopic means having correct vision or producing it. Orthoscopic, in other words, means free from optical distortion or designed to correct distorted vision. This fits with the prefix "ortho-", meaning straight or erect, and with "-scopic" from the Greek "skopein", to see. Orthoscopic literally is to see straight. Knee surgery performed with a small scope is arthroscopic knee surgery, not orthoscopic knee surgery.