Mikey's knee pads are uniquely decorated in Rise of the TMNT.
Joint pads are cushions which are worn by individuals on the joints of their limbs. Typically, they are seen on the elbows, wrists, shoulders, hips, knees, and ankles. Joint pads are used to soften blows accumulated to these joints, as well as to support joints that have been overstrained or damaged, and to prevent overstrain and damage to the joints through repetitive movement.
The Ninja Turtles are often depicted as wearing joint pads, which are brown in every incarnation except the classic 1987 TV series and Rise of the TMNT, in which they are the same color as their bandanas. Specific locations of joint pads may differ between incarnation and even between each turtle. Most often, they are located on the turtles at their wrists, elbows, and knees.