An endoscope uses two (2) fiber optic lines. A "light fiber" carries light into the body cavity and an "image fiber" carries the image of the body cavity back to the physician's viewing lens. There is also a separate port to allow for administration of drugs, suction, and irrigation. This port may also be used to introduce small folding instruments such as forceps, scissors, brushes, snares and baskets for tissue excision (removal), sampling, or other diagnostic and therapeutic work.

Endoscopes may be used in conjunction with a camera or video recorder to document images of the inside if the joint or chronicle an endoscopic procedure. New endoscopes have digital capabilities for manipulating and enhancing the video images.

Endoscopy can be used to diagnose various conditions by close examination of internal organ and body structures. Endoscopy can also guide therapy and repair, such as the removal of torn cartilage from the bearing surfaces of a joint. Biopsy (tissue sampling for pathologic testing) may also be performed under endoscopic guidance. Local or general anesthetic may be used during endoscopy, depending upon the type of procedure being performed.