Clinical UM Guideline

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

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.

The following codes for treatments and procedures applicable to this document are included below for informational purposes. Inclusion or exclusion of a procedure, diagnosis or device code(s) does not constitute or imply member coverage or provider reimbursement policy. Please refer to the member's contract benefits in effect at the time of service to determine coverage or non-coverage of these services as it applies to an individual member.

Prostheses
When services may be Medically Necessary when criteria are met:

When services are Not Medically Necessary:
For the procedure codes listed above when criteria are not met or for situations designated in the Clinical Indications section as not medically necessary.

Additions/Repair/Accessories
When services may be Medically Necessary when criteria are met:

Mechanical prosthetic devices are widely recognized as consistent with generally accepted standards of medical practice for individuals with extremity amputations from any cause. The need for a specific type of mechanical prosthetic limb and related components/additions is based upon demonstrated medical need, ability to utilize a particular device, and the expectations of the ordering provider regarding the likely post-treatment functional level.

Potential functional ability is based upon many factors, including but not limited to:

1. The individual’s past history and level of activity (including prior prosthetic use if applicable).
2. The individual’s current condition including the status of the residual limb and the nature of other medical problems.
3. The individual’s likely ability for community-based ambulation.

Functional Levels, also known as ‘K Levels’, are used to guide the appropriateness of lower limb prosthesis (Balk, 2018). Please note that within the functional classification hierarchy, bilateral amputees often cannot be strictly bound by functional level classifications.

Level 0:  Does not have the ability or potential to ambulate or transfer safely with or without assistance and prosthesis does not enhance their quality of life or mobility.
Level 1:  Has the ability or potential to use prosthesis for transfers or ambulation on level surfaces at fixed cadence. Typical of the limited and unlimited household ambulator.
Level 2:  Has the ability or potential for ambulation with the ability to traverse low-level environmental barriers such as curbs, stairs or uneven surfaces. Typical of the limited community ambulator.
Level 3:  Has the ability or potential for ambulation with variable cadence. Typical of the community ambulator who has the ability to traverse most environmental barriers and may have vocational, therapeutic, or exercise activity that demands prosthetic utilization beyond simple locomotion.
Level 4:  Has the ability or potential for prosthetic ambulation that exceeds basic ambulation skills, exhibiting high impact, stress, or energy levels. Typical of the prosthetic demands of the child, active adult, or athlete.

Hofstad and colleagues (2004) published a systematic review evaluating prosthetic ankle-foot mechanisms and the impact of daily functioning of individuals with lower limb amputation. A total of 26 studies were included, with a total of 245 individuals. The data indicated there may be a slight advantage in stride length and energy cost for individuals with transfemoral amputation utilizing the Flex-foot on level walking ground. However, the authors concluded that overall, there is insufficient evidence to conclude that one prosthetic design is superior to another, such as the Flex-foot versus the SACH (solid ankle, cushioned heel) foot.

Balk and colleagues (2018) published the results of a comparative effectiveness review of lower limb prostheses and what factors best determine the prosthetic configuration that is optimal for an individual with an amputation. The authors reviewed assessment techniques, prediction tools, and functional outcome measurement tools through 80 eligible studies with a focus on tools that are generalizable to the Medicare population. For all outcomes evaluated, the authors concluded that there is low or insufficient evidence. The studies that were available had methodological limitations, inconsistent findings, and few studies reported outcomes of interest. There is insufficient evidence to predict success and added benefit from a specific prosthesis, including components and configuration, for subgroups of amputees. Furthermore, no assessment instruments have been identified that reliably predict individual success based on prosthesis configuration.

In 2017 the Veteran’s Affairs and Department of Defense (VA/DoD) published their clinical practice guideline for rehabilitation of individuals with lower limb amputation. This document provides guidance on prosthesis selection and states the following:

There are inconclusive studies regarding differences in socket design, prosthetic foot categories, as well as advantages and disadvantages of various types of suspensions and interfaces. Each component of a prosthetic prescription should be carefully selected based on the capabilities and anticipated compliance of the user as well as the integrity and shape of the residual limb. Patient desired outcomes, patient goals, and the compatibility of the entire prosthetic system should also be a consideration when prescribing prosthetic components

Additionally, they recommend full consideration of the individual’s health status when relevant to prosthetic use outcomes:

8. We recommend an assessment of factors that are associated with poorer outcomes following acquired limb loss, such as smoking, comorbid injuries or illnesses, psychosocial functioning, and pain.

Some prosthetics and prosthetic accessories are designed specifically for use during leisure or sporting activities such as running, biking, or swimming. Such devices provide functionality above what may be considered necessary for routine daily activities for an individual or may be beyond what may be considered clinically appropriate for an individual. The use of a prosthetic device designed and intended specifically for use during leisure or sporting activities does not primarily serve a medical purpose. That use is thus considered not medically necessary.

Overall, the available evidence for the selection of prosthetic devices is poor, and the available recommendations emphasize a holistic approach taking multiple factors into consideration, including the individual’s health and functional status, as well as potential functional abilities and use.

Peer Reviewed Publications:

1. Hofstad C, Linde H, Limbeek J, Postema K. Prescription of prosthetic ankle-foot mechanisms after lower limb amputation. Cochrane Database Syst Rev. 2004;(1):CD003978.
2. Lovegreen W, Murphy DP, Smith WK, et al. Lower Limb Amputation and Gait. In: Cifu DX ed, Braddom's Physical Medicine and Rehabilitation, 5th Ed. Philadelphia, PA: Elsevier, 2016: 191-223.

Government Agency, Medical Society, and Other Authoritative Publications:

1. Balk EM, Gazula A, Markozannes G, et al. Comparative Effectiveness Review Number 213. Lower limb prostheses: measurement instruments, comparison of component effects by subgroups, and long-term outcomes. Agency for Healthcare Research and Quality. 2018 September. Available at: https://effectivehealthcare.ahrq.gov/sites/default/files/related_files/cer-213-lower-limb-protheses-report.pdf. . Accessed on June 26, 2024. 
2. Centers for Medicare & Medicaid Services. Activities of Daily Living. 2008. Available at: https://www.cms.gov/research-statistics-data-and-systems/research/mcbs/downloads/2008_appendix_b.pdf. Accessed on June 26, 2024.
3. Centers for Medicare & Medicaid Services. Health Technology Assessment. Lower Limb Prosthetic Workgroup. Consensus Document. September 2017. Available at: https://www.cms.gov/Medicare/
   Coverage/DeterminationProcess/downloads/LLP_Consensus_Document.pdf. Accessed June 26, 2024.
4. Veteran’s Affairs/ Department of Defense. VA/DoD Clinical Practice Guideline for Rehabilitation of Individuals with Lower Limb Amputation. 2017. Available at: https://www.healthquality.va.gov/guidelines/Rehab/amp/VADoDLLACPG092817.pdf. Accessed on June 26, 2024.

Lower Leg
Prosthesis
SACH Foot

The use of specific product names is illustrative only. It is not intended to be a recommendation of one product over another, and is not intended to represent a complete listing of all products available.