Microprocessor-Controlled Prostheses for the Lower Limb*
Medical Policy: 01.01.07
Original Effective Date: August 2002
Reviewed: February 2012
Revised: December 2009
Benefit Application
Benefit determinations are based on the applicable contract language in effect at the time the
services were rendered. Exclusions, limitations or exceptions may apply. Benefits may vary
based on contract, and individual member benefits must be verified. Wellmark determines medical
necessity only if the benefit exists and no contract exclusions are applicable. This medical
policy may not apply to FEP. Benefits are determined by the Federal Employee Program.
This Medical Policy document describes the status of medical technology at the time the document
was developed. Since that time, new technology may have emerged or new medical literature may
have been published. This Medical Policy will be reviewed regularly and be updated as scientific
and medical literature becomes available.
Description:
Pneumatic and hydraulic prosthetic knee joints enable the trans-femoral amputee to demonstrate a comfortable gait and a wide range of walking speeds. By adding a microprocessor to the pneumatic and hydraulic prosthesis, the amputee’s walking style may be improved. Microprocessor controlled prosthetic knee (e.g. the C-Leg®, the Adaptive, the Rheo, and the Intelligent Prosthesis) electronically controls the prosthesis through the stance and the swing phase, allowing increased safety and speed on even and uneven surfaces, as well as on stairs. The microprocessor control of this prosthesis is based on scientific gait analysis and biomechanical studies that detect step time and alter knee extension level to suit walking speed. Some more advanced models, such as the Otto-Bock C-Leg®, have multiple sensors that gather and calculate data on various parameters such as the amount of vertical load, ankle movement, and knee joint movement in an attempt to mimic more natural leg function to provide stability and gait fluidity as needed on uneven terrains and/or during sports activities. By improving stance control, they may provide increased safety, stability, and function; for example, the sensors are designed to recognize a stumble and stiffen the knee, thus avoiding a fall. Besides the improved ability to navigate stairs, slopes, and uneven terrain, the microprocessor-controlled knee prostheses have another potential benefit of reduction in energy expenditure and concentration required for ambulation.
A microprocessor-controlled knee may be considered in amputees who demonstrate a need for long distance ambulation at variable rates (use of the limb in the home or for basic community ambulation is not sufficient to justify provision of the computerized limb over standard limb applications) or demonstrate need for regular ambulation on uneven terrain or for regular use on stairs (use of the limb for limited stair climbing in the home or employment environment is not sufficient evidence for prescription of this device over stand prosthetic application).
Microprocessor-controlled ankle-foot prostheses are being developed for transtibial amputees. The only microprocessor-controlled foot prosthesis that is available is the Proprio Foot®. Sensors in the feet determine the direction and speed of the foot’s movement, allowing the foot to lift during the swing phase and adjust to changes in force, speed and terrain during the step phase. The intent of the technology is to make ambulation more efficient and prevent falls in patients ranging from the young active amputee to the elderly diabetes patient . It is indicated for low to moderate impact for transtibial amputees who are classified as community ambulatory, with the ability or potential for ambulation with variable cadence.
In development are lower-limb prostheses that also replace muscle activity in order to bend and straighten the prosthetic joint. For example, the Power Foot®, is a myoelectric prosthesis for transtibial amputees that use muscle activity from the remaining limb for the control of ankle movement. This prosthesis is designed to propel the foot forward as it pushes off the ground during the gait cycle, which in addition to improving efficiency, has the potential to reduce hip and back problems arising from an unnatural gait with use of a passive prosthesis. The Power KneeTM, which is designed to replace muscle activity of the quadriceps, uses artificial proprioception with sensors similar to the Proprio Foot® in order to anticipate and respond with the appropriate movement required for the next step.
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Prior Approval:
Prior approval is recommended. Submit a prior approval now. 
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Policy:
A microprocessor-controlled prosthetic knee may be considered medically necessary for patients who are successfully utilizing a hydraulic or pneumatic swing and stance control knee prosthesis or for patients who have recently undergone an amputation. The following criteria must be met:
- The patient should not have any major cardiovascular, musculoskeletal or neuromuscular problems
- The patient must meet the manufacturer’s specifications and limitations for a microprocessor-controlled system and must be fitted by a prosthetist certified by the manufacturer
- Second opinion by the attending physician and prosthetist is required for the early replacement of the prosthesis
AND
In addition, for patients who are successfully utilizing a hydraulic or pneumatic swing and stance control knee prosthesis the following criteria must also be met:
- A gait analysis must be performed by an independent orthopedic gait lab facility using the patient’s existing hydraulic or pneumatic swing and stance control knee prosthesis
- The patient’s gait analysis must demonstrate potential for improved gait efficiency as stated in our Medical Policy on Gait Analysis (Policy 02.01.10). Note: If a patient who has not met the manufacturer’s specifications is referred to a gait lab for analysis, the gait lab charges will be the responsibility of the referring provider.
The use of the microprocessor-controlled prosthetic knee is considered not medically necessary if the criteria listed above are not met.
A powered knee is considered investigational.
A microprocessor-controlled ankle-foot is considered investigational.
A microprocessor-controlled or powered foot is considered investigational.
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Procedure Codes and Billing Guidelines:
- To report provider services, use appropriate CPT* codes, Modifiers, Alpha Numeric (HCPCS level 2) codes, Revenue codes, and/or ICD-9 diagnostic codes
- L5856 Addition to lower extremity prosthesis, endoskeletal knee-shin system, microprocessor control feature, swing and stance phase, includes electronic sensor(s), any type
- L5857 Addition to lower extremity prosthesis, endoskeletal knee-shin system, microprocessor control feature, swing phase only, includes electronic sensor(s), any type
- L5858 Addition to lower extremity prosthesis, endoskeletal knee shin system, microprocessor control feature, stance phase only, includes electronic sensor(s), any type
- L5973 Endoskeletal ankle foot system, microprocessor controlled feature, dorsiflexion and/or plantar flexion control, includes power source
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Selected References:
- Datta D, Howitt J. Conventional versus microchip controlled pneumatic swing phase control for trans-femoral amputees: user’s verdict. Prosthetics and orthotics International 1998; 22:129-135.
- VA Technology Assessment Program, Short Report- Computerized Lower Limb Prostheses. March 2000, Number 2.
- State of Washington, Department of Labor and Industries, Office of the Medical Directory Technology Assessment. Microprocessor-Controlled Prosthetic Knees. Rev August 2002
- Stinus H Biomechanics and evaluation of the microprocessor-controlled C-Leg exoprosthesis knee joint. Z Orthop Ihre Grenzgeb. 2000 May-Jun;138(3):278-82. (Abstract viewed on Pub Med)
- Wetz HH, Hafkemeyer U, Drerup B. The influence of the C-leg knee-shin system from the Otto Bock Company in the care of above-knee amputees A clinical-biomechanical study to define indications. Orthopade. 2005 Apr;34(4):298-319
- Wellmark’s Home Medical Equipment, Orthotics, and Prostheses Guide can be found at http://www.wellmark.com/products/providers/publications/HME.pdf.
- California Technology Assessment Forum (CTAF). Microprocessor-controlled prosthetic knees. A Technology Assessment. San Francisco, CA: CTAF; October, 2007. Available at: http://ctaf.org/content/general/detail/777. Accessed 11/12/2009.
- Hafner BJ, Willingham LL, Buell NC, et al. Evaluation of function, performance, and preference as transfemoral amputees transition from mechanical to microprocessor control of the prosthetic knee. Arch Phys Med Rehabil. 2007;88(2):207-217.
- ECRI Institute. Microprocessor-controlled Lower Extremity Prostheses. Plymouth Meeting (PA): ECRI Institute; 2008 April 10. 9 p. [ECRI hotline response]. Also available: http://www.ecri.org.
- ECRI Institute. Microprocessor-controlled Ankle-Foot Prostheses. Plymouth Meeting (PA): ECRI Institute; 2008 July 30. 6 p. [ECRI hotline response]. Also available: http://www.ecri.org.
- Kaufman KR, Levine JA, Brey RH, McCrady SK, Padgett DJ, Joyner MJ. Energy expenditure and activity of transfemoral amputees using mechanical and microprocessor-controlled prosthetic knees. Arch Phys Med Rehabil. 2008 Jul;89(7):1380-5.
- Versluys R, Beyl P, Van Damme M et al. Prosthetic feet: State-of-the-art review and the importance of mimicking human ankle-foot biomechanics. Disabil Rehabil Assist Technol. 2009 Mar;4(2):65-75.
- ECRI Institute. Microprocessor-controlled ankle-foot prostheses. Plymouth Meeting (PA): ECRI Institute; 2010 Jul 21. 6p. [ECRI hotline response]. Also available: http://www.ecri.org.
- Health technology forecast [database online]. Plymouth Meeting (PA): ECRI Institute; 2010 Aug 20. Improved microprocessor knee prosthetic implanted in veterans. Available: http://www.ecri.org.
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Policy History:
Date Reason Action
April 2011 Annual review Policy renewed
February 2012 Annual review Policy renewed
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of technology assessment of new and emerging treatments, devices,
drugs, etc. They are developed to
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and therefore are subject to change without notice.
*Current Procedural Terminology © 2012 American Medical Association. All Rights Reserved.
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