This document addresses the use of lower limb prostheses required to replace the function of a lower limb loss due to trauma, disease, or a congenital condition.

Note: For information addressing microprocessor-controlled leg or foot-ankle prosthesis please refer to:

• CG-OR-PR-08 Microprocessor Controlled Lower Limb Prosthesis

Clinical Indications

I.  Lower Limb: Prosthesis Fitting and Selection

Medically Necessary:

A lower limb prosthesis is considered medically necessary when all the following are met and are documented in the medical record:

1. The prosthesis is prescribed by physician; and
2. The member will reach or maintain a defined functional state within a reasonable period of time; and
3. The member needs prosthesis for ambulation; and
4. The member’s rehabilitation potential is based on Functional Levels (also known as ‘K-Levels’, see Discussion section below for more information); and
5. The following anatomy-specific criteria apply:
   1. Ankles:
      An axial rotation unit is considered medically necessary for individuals whose functional level is 2 or above.
   2. Knees: 
      Basic lower extremity prostheses include a single axis, constant friction knee. Prosthetic knees are considered for medical necessity based upon functional classification:
      1. Fluid and pneumatic knees are considered medically necessary for members with a functional Level 3 or above.
      2. Other knee systems are considered medically necessary for members with a functional Level 1 or above.
   3. Sockets:
      1. Up to 2 test (diagnostic) sockets for an individual prosthesis are medically necessary without additional documentation.
      2. Socket replacements are considered medically necessary if there is adequate functional documentation of physiological need, including, but not limited to:
         1. Changes in the residual limb; or
         2. Functional need changes; or
         3. Irreparable damage; or
         4. Wear/tear due to excessive member weight or prosthetic demands of very active amputees.
   4. Feet:
      The treating physician or the prosthetist will make the determination of the type of foot needed for the prosthesis based upon the functional needs of the individual. Basic lower extremity prostheses include a SACH foot. Other prosthetic feet are considered for medical necessity based upon functional classification.
      1. An external keel SACH foot or single axis ankle/foot is considered medically necessary for individuals whose functional level is 1 or above.
      2. A flexible-keel foot or multi-axial ankle/foot is considered medically necessary for individuals whose functional level is 2 or above.
      3. A flex foot system, energy storing foot, multi-axial ankle/foot, dynamic response, or flex-walk system or equal, or shank foot system with vertical loading pylon is considered medically necessary for individuals whose functional level is 3 or above.

Not Medically Necessary:

A lower limb prosthesis is considered not medically necessary when the criteria above have not been met.

A lower limb prosthesis is considered not medically necessary for individuals with a functional level of 0.

Prosthetics utilized primarily for leisure or sporting activities are considered not medically necessary.

Test (diagnostic) sockets for immediate post-surgical or early fitting prostheses are considered not medically necessary.

More than two test (diagnostic) sockets for an individual prosthesis are considered not medically necessary without additional documentation of need.

More than two of the same socket inserts are considered not medically necessary per individual prosthesis at the same time.

II.  Lower Limb: Accessories, Maintenance, Repairs and Replacement

Medically Necessary:

Accessories (for example, stump stocking for the residual limb, harness, etc.) are considered medically necessary when these appliances aid in, or are essential to, the effective use of the artificial limb.

Repairs to a prosthesis are considered medically necessary when necessary to make the prosthesis functional.

Maintenance that may be necessitated by manufacturer’s recommendations or the construction of the prosthesis and must be performed by the prosthetist is considered medically necessary as a repair.

Adjustments to a prosthesis required by wear and tear or change in an individual’s condition are considered medically necessary.

Replacement of a prosthesis or prosthetic component is considered medically necessary if the treating physician orders a replacement device or part because of either of the following:

1. A change in the physiological condition of the individual; or
2. Irreparable wear of the device or a part of the device.

Not Medically Necessary:

Prosthetic accessories, additions, or components used primarily for leisure or sporting activities are considered not medically necessary under all conditions.