Because the arthroscope and surgical instruments are thin, your surgeon can use very small incisions, rather than the larger incision needed for open surgery. This results in less pain for patients, less joint stiffness, and often shortens the time it takes to recover and return to favorite activities. During arthroscopy, your surgeon can see the structures of your knee in great detail on a video monitor.
For a function of three variables, a level set is a surface in three-dimensional space that we will call a level surface. For a constant value $c$ in the range of $f(x,y,z)$, the level surface of $f$ is the implicit surface given by the graph of $c=f(x,y,z)$.
SET is also an acronym for Secure Electronic Transaction. A set is a group or collection of objects or numbers, considered as an entity unto itself. Sets are usually symbolized by uppercase, italicized, boldface letters such as A, B, S, or Z. Each object or number in a set is called a member or element of the set. Examples include the set of all computers in the world, the set of all apples on a tree, and the set of all irrational numbers between 0 and 1.