The L1833 is a code given to an "off-the shelf" knee brace which meats certain criteria and standards. L1833 knee braces must have adjustable knee joints, the adjustments may come from one point of origin or several. In addition to being an adjustable knee brace, the L1833 must also be a positional orthosis, which means the brace provides positional control of the knee.
The "off-the shelf" status of this code means the brace does not need to be fitted by a qualified professional in order to be classified as an L1833 knee brace.