A Knee Walker or Knee Scooter is a three or four-wheeled alternative to crutches or a traditional walker as an ambulation aid. It is known by many other names, such as a knee cruiser, knee caddy, orthopedic scooter, podiatry scooter or leg walker.

Over the years it has taken on many forms, from small-wheeled devices suitable for indoor use to larger sturdier units capable of use outside on grass or paved surfaces. Today’s version is usually a lightweight, foldable design that, with the knee flexed, supports the shin of the unusable limb. The opposite foot makes contact with the floor or ground, providing propulsion.

The objective of the scooter is to create a safe, comfortable, and easy-to-maneuver alternative to the traditional crutch. Prior to its introduction, those experiencing foot surgery, bunionectomies, gout, below the knee amputations, diabetic ulcers and wounds, as well as foot sprains, or fractures had no choice but to limit activity during rehabilitation. Their only options were crutches, a traditional walker, a wheelchair or bed rest.

The scooter does have limitations that may make it unsuitable for some patients, such as those with leg injuries above or near the knee. It cannot negotiate stairs, and is significantly heavier and more difficult to load into a vehicle than crutches.