In simple words: This code is for a special computer-controlled part added to an artificial knee and lower leg. It helps the person control the leg's movement when it swings forward while walking. It's for people who have had a leg amputated above or at the knee and can walk well enough to benefit from this technology.

This code represents the addition of a microprocessor control feature to an endoskeletal knee-shin system to control the swing phase of gait. This device uses a battery-operated, microprocessor-controlled hydraulic knee that analyzes data from electronic sensors to control swing phase. It is prescribed for patients with transfemoral or knee disarticulation amputations who can walk frequently and quickly and perceive vibrations and acoustic signals from the microprocessor. The microprocessor assists with walking on uneven surfaces and stairs. This system is used with an endoskeletal prosthesis, which has an internal support mechanism.

Example 1: A patient with a transfemoral amputation who is an active community ambulator (K3) requires a microprocessor-controlled knee to improve stability and gait on uneven terrain., A patient with a knee disarticulation who has a high activity level (K4) needs a microprocessor knee to support running and other high-impact activities., A patient with a transfemoral amputation and a K2 functional level would not be an appropriate candidate for the L5857 as per certain payer guidelines which require K3-K4. Therefore the patient recieves L5614 instead of L5857 for basic ambulation needs.

Documentation must include the patient's functional level assessment (K0-K4), amputation details, medical necessity justification, and the chosen prosthesis components.

** The L5857 code specifically covers the swing phase control feature of the microprocessor knee. Other codes, such as L5856 and L5858 cover stance phase or both swing and stance control. This is a complex device, and proper documentation is essential for reimbursement.