Lower Limb Prosthetics, Including Microprocessor Prosthetics
Durable Medical Equipment
© Blue Cross and Blue Shield of Montana
Current Effective Date:
February 01, 2014
Original Effective Date:
July 18, 2013
January 15, 2014
January 15, 2014
Amputated and/or missing limbs result from accidents, disease, and congenital disorders. A lower limb prosthetic is a device or artificial substitute designed to replace the function and/or appearance of the absent limb.
The patient’s condition is an important factor to consider in choosing a prosthesis. To be functionally successful with a prosthesis, the patient must demonstrate sufficient trunk control, good upper body strength, static and dynamic balance, and adequate posture. The basic goals with prosthetic use are stability, ease of movement, energy efficiency, and appearance of a natural gait. The prescription for a prosthesis depends on the activity level and specific needs of each individual patient. Clinical assessment of the patient’s rehabilitation potential should be based on the following functional levels:
Level 0: Does not have the ability or potential to ambulate or transfer safely with or without assistance and a prosthesis does not enhance his/her quality of life or mobility.
Level 1: Has the ability or potential to use a prosthesis for transfers or ambulating on level surfaces at fixed cadence; typical of the limited and unlimited household ambulator.
Level 2: Has the ability or potential for ambulating with the ability to traverse environmental barriers such as curbs, stairs, or uneven surfaces; typical of the limited community ambulator.
Level 3: Has the ability or potential for ambulating 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 ambulating that exceeds basic ambulating skills, exhibiting high impact, stress, or energy levels; typical of the prosthetic demands of the child, active adult, or athlete.
Generally, the earlier a prosthesis is fitted, the better it is for the amputee. Early ambulation helps keep the patient active, accelerates stump shrinkage, helps prevent flexion contractures, and can reduce phantom limb pain. Immediate postsurgical or early fitting procedures are typically performed in the hospital setting immediately after surgery. These procedures include specific dressings and fittings that are intended to prepare the residual limb for a prosthesis. An initial (preparatory) prosthesis and/or immediate postoperative prosthesis (IPOP) may be used to accelerate the rehabilitation process. It is intended to be temporary for several weeks or months until the stump stabilizes and a permanent (definitive) prosthesis is fitted. The base initial and preparatory prostheses include the necessary elements, and usually additions and/or substitutions are not required. However, many physicians prefer to postpone prosthetic intervention until the wound is healed. If necessary, a patient can be fitted for a definitive prosthesis without ever having a preparatory prosthesis. In this case, the socket fitting should be delayed until the residual limb is fully mature (usually 3-4 months) or until the patient’s weight and stump circumference have stabilized.
There is no precise prescription for lower limb prostheses as fitting a prosthesis is very individualized to each patient. A poorly designed or badly fitted prosthesis can be as disabling as the actual amputation. A prosthesis with components that are appropriate for functional level and physical condition helps the patient avoid future medical problems and injury to the residual limb.
Amputation level is a factor to consider in choosing a prosthesis. The following list identifies the base prosthesis for different levels of amputation:
- Partial foot prosthesis (PFP)—for absence of the foot and/or toes below the ankle.
- Ankle (Syme's) Prosthesis (SP)—for absence of the foot and ankle just above the ankle joint.
- Below Knee Prosthesis (BKP)—for absence of the foot and ankle below the knee joint.
- Above Knee Prosthesis (AKP)—for absence of the foot, ankle, shin and thigh above the knee joint.
- Knee Disarticulation Prosthesis (KDP)—for absence of the foot, ankle and shin at the knee joint level.
- Hip Disarticulation Prosthesis (HDP)—for absence of the complete leg including the foot, ankle, shin and thigh at the hip joint level.
- Hemipelvectomy Prosthesis (HP)—for absence of the complete leg including the foot, ankle, shin, thigh, hip and pelvis.
A lower limb prosthesis is made up of a base prosthesis combined with the possible addition of any of the following components:
- Prosthetic sock or liner;
- Socket inserts;
- Pylon, or knee-shin system;
- Articulating joint;
- Suspension system;
- Protective outer covering;
- Foot, ankle, or foot-ankle system.
Each additional or “add-on” component requires justification with regard to medical necessity related to activities of daily living.
The socket is the basis for the connection between the patient and the prosthesis, and a good fit is extremely important to the success of the prosthesis. The most common socket for the BKP is a Patellar-Tendon-Bearing (PTB) design. With an AKP, the transected femur can support very little weight at its end, so the socket is designed to shift the weight onto the side of the thigh and the pelvis. The quadrilateral socket has a contoured area called the ischial seat that supports the ischium (part of the hip bone). The ischial containment socket is made of more flexible materials, and encapsulates the ischium in a way that provides more stability and control. Sockets can be flexible, expandable, or rigid, and are made of a variety of materials including wood, leather, polyester, acrylic, carbon, plastic, or a combination of these. For example, a rigid carbon frame over a flexible inner socket offers strength and stability with flexibility and comfort.
Prosthetic socks provide comfort and ventilation, and help prevent skin abrasion. They should be changed and laundered daily to reduce skin irritation and dermatitis. Prosthetic liners and socket inserts are made of soft material or gel that is molded to the residual limb and acts as an interface between the hard weight-bearing socket and the skin. The suspension system attaches the prosthesis to the residual limb. This system can be a variety of belts, wedges, straps, suction, inserts, or some combination of these.
Knee-shin systems can be exoskeletal (crustacean) or endoskeletal. The exoskeletal knee-shin system is a one-piece design that entails wood or foam enclosed by a hard plastic finish, usually shaped like a leg, and without interchangeable parts. This type of knee-shin system is very durable and simple. Because it is sturdy and heavy duty, it may be preferred by people who will be in harsh environments, such as farmers or other outdoor workers. Endoskeletal knee-shin systems are more complex and have interchangeable parts under a soft outer cover. Endoskeletal systems are lightweight and have many different component options, such as different knee units that can be introduced as the patient’s functional needs change.
The knee joint has three functions: provide support during stance phase of ambulation, produce smooth control during swing phase, and maintain unrestricted motion for sitting and kneeling. More than 100 different prosthetic knee and ankle/foot designs are currently available. The choice of the most appropriate design may depend on the patient’s underlying activity level. For example, the requirements of a prosthetic knee in an elderly, largely homebound individual will be quite different than a younger, active person. In general, key elements of a prosthetic knee design involve providing stability during both the stance phase and swing phase of the gait. Prosthetic knees also vary in their ability to alter the cadence of the gait, or the ability to walk on rough or uneven surfaces. In contrast to more simple prostheses, which are designed to function optimally at one walking cadence, fluid and hydraulic-controlled devices are designed to allow amputees to vary their walking speed by matching the movement of the shin portion of the prosthesis to the movement the upper leg. For example, the rate at which the knee flexes after “toe-off” and then extends before heel strike depends in part on the mechanical characteristics of the prosthetic knee joint. If the resistance to flexion and extension of the joint does not vary with gait speed, the prosthetic knee extends too quickly or too slowly relative to the heel strike when the cadence is altered. When properly controlled, hydraulic or pneumatic swing-phase controls allow the prosthetist to set a pace that is adjusted to the individual amputee from a very slow pace to a race-walking pace. Hydraulic prostheses are heavier than other options and require gait training; for these reasons, these prostheses are generally prescribed for athletic or fit individuals. Other design features include multiple centers of rotation, referred to as “polycentric knees.” The mechanical complexity of these devices allows engineers to optimize selected stance and swing-phase features. The following are prosthetic knee options:
- Manual locking knee is a very stable knee that is locked during gait. The patient releases the lock mechanism manually to sit down. This knee may be used for patients who have very short residual limb and/or poor hip strength and are unable to control the knee.
- Single-axis constant friction knee has a simple hinge and single pivot point. These knees are set to walk at one speed, and do not have stance control.
- Weight-activated stance control knee is a single-axis constant friction knee with a braking mechanism. When the patient puts his weight on the knee during gait, a braking mechanism is applied and the knee won’t buckle.
- Polycentric knees, also referred to as 4-bar knees, have multiple centers of rotation allowing for stability at all phases of gait. The 4-bar linkage allows the knee to collapse better during the swing phase and to bend easier for sitting. These can incorporate a hydraulic or pneumatic unit to permit variable walking speeds.
- Pneumatic or hydraulic knees have pistons inside cylinders containing air (pneumatic) or fluid (hydraulic); these units adjust gradually to changes in gait speed, which allows walking at variable speeds and permits a somewhat more natural gait.
- Microprocessor-controlled prosthetic knees have been developed, including the Intelligent Prosthesis (Blatchford, U.K.), the Adaptive (Endolite, England), the Rheo (Ossur, Iceland), and the C-Leg (Otto Bock Orthopedic Industry, Minneapolis, MN). These devices are equipped with a sensor that detects when the knee is in full extension and adjusts the swing phase automatically, permitting a more natural walking pattern of varying speeds. For example, the prosthetist can specify several different optimal adjustments that the computer later selects and applies according to the pace of ambulation. In addition, many of these devices use microprocessor control in both the swing and stance phases of gait. 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. Other potential benefits of microprocessor-controlled knee prostheses are improved ability to navigate stairs, slopes, and uneven terrain, and reduction in energy expenditure and concentration required for ambulation.
- The C-Leg was cleared for marketing in 1999 through the 510(k) process of the U.S. Food and Drug Administration (FDA, K991590). The C-Leg is versatile, controls both stance and swing, performs better on stairs, and must be combined with one of five specific foot devices.
- The Rheo Knee is very comparable to the C-Leg, and can be combined with any foot device.
- The Adaptive Knee also has both swing and stance control, but because it is lightweight, durable, and has more emphasis on swing than stance, this knee is well-suited to patients who are very strong and active at a higher functional level.
- Otto Bock’s Compact is designed for stability in stance phase, and does not have swing microprocessors. This knee would be a good choice for an appropriately active patient with focus on stability, where gait speed is not as important an issue.
- Knees with processors for swing-only have a lesser degree of stance control, and are considered a clinical option when the patient has a higher activity level combined with a very high residual limb control; examples include the DAW, Intelligent Knee, IP+, Smart IP, and Seattle Power Knee.
The basic functions of the prosthetic foot are to provide a stable weight bearing and shock absorbing surface, to replace lost muscle function, and to replicate the anatomic joint. Conventional prosthetic feet can be basic (non-articulated, unmoving), articulated or dynamic-response (energy-storing). Articulated feet have one or more joints. The single-axis foot has one joint, and can be used to help keep the knee stable. The multi-axis foot has motion about all three axes of the ankle and is good for walking on uneven surfaces. The multi-axis and dynamic-response feet are energy-storing feet. An energy-storing foot is capable of absorbing energy in a flexible keel (horizontal device in the foot) during the roll-over part of the stance phase of gait. The keel then springs back to provide push-off assistance to get the toe off the ground to start the swing phase. The simplest type of non-articulated foot is the SACH (solid ankle-cushion heel) foot, which has a rigid keel, and a soft rubber heel that provides ankle action. The SAFE (solid ankle-flexible-endoskeletal) foot has the same action as the SACH plus the sole is able to conform to irregular surfaces, which makes it easier to walk on uneven terrain. The SAFE foot is also called a “flexible keel foot”. The SACH and SAFE feet are non-energy-storing feet.
Microprocessor-controlled ankle-foot prostheses are being developed for transtibial amputees. These include the Proprio Foot (Ossur) and the iPED (developed by Martin Bionics LLC and licensed to College Park Industries). With sensors in the feet that determine the direction and speed of the foot’s movement, a microprocessor controls the flexion angle of the ankle, allowing the foot to lift during the swing phase and potentially 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 diabetic patient. The Proprio Foot is the only microprocessor-controlled foot prosthesis that is commercially available at this time and is a class-I device that is exempt from 510(k) marketing clearance. The manufacturer must register the prosthesis with the restorative devices branch of the FDA and keep a record of any complaints but does not have to undergo a full review. Information on the Ossur website indicates use of the Proprio Foot for low- to moderate- impact for transtibial amputees who are classified as level K3 (i.e., community ambulatory, with the ability or potential for ambulation with variable cadence). According to Ossur, the Proprio Foot is the first and only microprocessor foot to utilize the power of artificial intelligence with Terrain Logic™ software. In just 15 steps, individual style of walking is traced and recorded as a “gait profile”. The customized “gait profile” is then automatically launched each time a step is taken. Terrain Logic™ software instantly adjusts and moves the foot when surfaces change. Amputees can quickly negotiate unexpected terrain without the risk of stumbling or falling. According to Ossur, the Proprio Foot ensures safety and stability by doing the following:
- Detects when the toe leaves the ground and lifts it, thereby resulting in the safe clearance of curbs and other irregularities in terrain.
- Positions the foot up or down to create natural function when sitting or standing.
- Places the foot solidly on steps and uneven ground to enhance stability and balance. Calibrated alignment control helps prevent premature knee flexion and knee hyperextension.
Microprocessor-Controlled Foot, Powered Foot and Knee, and New Generation Microprocessor Knee
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 (developed at the Massachusetts Institute of Technology and licensed to iWalk) is a myoelectric prosthesis for transtibial amputees that uses 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. This technology is limited by the size and the weight required for a motor and batteries in the prosthesis. The Power Knee (Ossur), 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. The Power Knee is currently in the initial launch phase in the United States. The Genium™ Bionic Prosthetic System is a new generation of microprocessor-controlled, intelligent knee prostheses. The Genium uses software with a complex sensory system, including a gyroscope and an accelerometer, creating a natural, intuitive gait. It is designed to anticipate the user’s movement, not just respond to them, with both swing and stance control predicted by multi-modal propriceptive input. The Endolite Êlan foot is another promising foot/ankle system with microprocessor controlled speed and terrain response. The Êlan has sensors that continuously monitor environmental feedback and an algorithm that changes the foot characteristic to provide safety, comfort and energy efficiency on flat ground, and descending or ascending ramps and stairs. (47)
Hydraulic Prosthetic Hip
Fitting and wearing hip disarticulation prostheses presents several challenges, including poor gait pattern, socket discomfort, instability, loss of mobility, prosthesis weight and energy expenditure. The Canadian hip disarticulation prosthesis was developed by McLaurin more than 50 years ago, and is the “standard” hip disarticulation prosthesis. These prostheses move in a single plane, and require locking of the knee and hip for walking and unlocking to sit down. A new prosthetic hip joint, the Helix3DHip® (OttoBock), consists of a four-axis mechanism with hydraulic stance and swing-through phase control, which is reported to have the advantages of greater support and stability, and three-dimensional movement similar to the ball joint of the natural hip, and more controlled heel strike.
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- Kirker, S., Keymer, S., et al. An assessment of the intelligent knee prosthesis. Clinical Rehabilitation 1996; 10(3):267-73.
- Buckley, J.G., Spence, W.D., et al. Energy cost of walking: comparison of “Intelligent Prosthesis” with conventional mechanism. Archives of Physical Medicine and Rehabilitation 1997; 78(3):330-3.
- Datta, D., and J. Howitt. Conventional versus microchip controlled pneumatic swing phase control for trans-femoral amputees: user’s verdict. Prosthetics and Orthotics International 1998; 22(2):129-35.
- Michael, J.W. Modern prosthetic knee mechanisms. Clinical Orthopaedics and Related Research 1999; (361):39-47.
- Angelico, John. Transfemoral Prosthetics, Above Knee. InMotion (May/June 1999) 9(3). http://amputee-coalition.org (Accessed 2005 March).
- U.S. Department of Veterans Affairs, Veterans Health Administration, Office of Research and Development, Health Service Research and Development Service, Management Decision and Research Center, Technology Assessment Program. Computerized lower limb prosthesis. VA Technology Assessment Program Short Report No. 2. Boston, Mass: MDRC, March 2000. Available at www.va.gov (Accessed 2011 March).
- Miller, W.C., Speechley, M., et al. The prevalence and risk factors of falling and fear of falling among lower extremity amputees. Archives of Physical Medicine and Rehabilitation 2001; 82:1031-6.
- Miller, W.C., Deathe, B., et al. The influence of falling, fear of falling, and balance confidence on prosthetic mobility and social activity among individuals with a lower extremity amputation. Archives of Physical Medicine and Rehabilitation 2001; 82:1238-44.
- Hafner, Brian J., et al. Transtibial energy-storage-and-return prosthetic devices: A review of energy concepts and a proposed nomenclature. Journal of Rehabilitation Research and Development 2002; 39(1):1-11. Available at http://www.vard.org (Accessed 2005 March).
- Baum, Robert. VA Embraces gait and limb technology. Capabilities. Northwestern University Prosthetics Research Laboratory and Rehabilitation Engineering Research Program 2002; 11(2):11-13. Available at http://www.repoc.northwestern.edu (Accessed 2005 July)
- Bodeau, Valerie S., et al. Lower limb prosthetics 2002; Available at http://www.emedicine.com (Accessed 2005 March).
- Miller, W.C., Speechley, M., et al. Balance confidence among people with lower limb amputations. Physical Therapy 2002; 82:9:856-65.
- Technology Assessment, Microprocessor-Controlled Prosthetic Knees. State of Washington Department of Labor and Industries, Office of Medical Directory 2002. Available at http://www.lni.wa.gov (Accessed 2005 July).
- Van der Linde, Hofstadt, C.J. et al. A systematic literature review of the effect of different prosthetic components on human functioning with a lower-limb prosthesis. Journal of Rehabilitation Research and Development 2004; 41(4):555-70.
- Smith, Douglas G. The transfemoral amputation level, Part 4, Great prosthetic components are good, but a good socket is great. InMotion 2004; 14(5).
- General Prosthetic Services. Orthotics and Prosthetics Rehabilitation Engineering Centre. Available at http://www.oanpcentre.com (Accessed 2005 February).
- VHA Prosthetic Clinical Management Program (PCMP). Clinical practice recommendations: microprocessor knees, 2004. See: Berry D. Microprocessor prosthetic knees. Phys Med Rehabil Clin N Am 2006; 17:91-113.
- Hofstad C, Linde H, Limbeek J et al. Prescription of prosthetic ankle-foot mechanisms after lower limb amputation. Cochrane Database Syst Rev 2004; (1):CD003978.
- Datta D, Heller B, Howitt J. A comparative evaluation of oxygen consumption and gait pattern in amputees using Intelligent Prostheses and conventionally damped knee swing-phase control. Clin Rehabil 2005; 19(4):398-403.
- Prosthetic knees. National Amputee Centre. The War Amps©2005. Available at http://waramps.ca (Accessed 2005 March).
- Manual for below-knee amputees. OMNI (Organising Medical Networked Information). University of Nottingham, UK. Available at http://www.omni.ac.uk (Accessed 2005 July).
- Manual for above-knee amputees. OMNI (Organising Medical Networked Information). University of Nottingham, UK. Available at http://www.omni.ac.uk (Accessed 2005 July).
- Johansson JL, Sherrill DM, Riley PO et al. A clinical comparison of variable-damping and mechanically passive prosthetic knee devices. Am J Phys Med Rehabil 2005; 84(8):563-75.
- Swanson E, Stube J, Edman P. Function and body image levels in individuals with transfemoral amputations using the C-Leg. J Prosthet Orthot 2005; 17(3): 80-4.
- Pauley, T., Devlin, M., et al. Falls sustained during inpatient rehabilitation after lower limb amputation: prevalence and predictors. American Journal of Physical Medicine and Rehabilitation 2006; 85:521-32.
- Department of Veterans Affairs Fact Sheet, VA’s Prosthetics and Sensory Aids. February 2006. Available at: http://www1.va.gov (Accessed March 2007).
- Orendurff MS, Segal AD, Klute GK et al. Gait efficiency using the C-Leg. J Rehabil Res Dev 2006; 43(2):239-46.
- Klute GK, Berge JS, Orendurff MS et al. Prosthetic intervention effects on activity of lower-extremity amputees. Arch Phys Med Rehabil. 2006; 87(5):717-22.
- Williams RM, Turner AP, Orendurff M et al. Does having a computerized prosthetic knee influence cognitive performance during amputee walking? Arch Phys Med Rehabil 2006; 87(7):989-94.
- 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):207-17.
- Seymour R, Engbretson B, Kott K et al. Comparison between the C-leg(R) microprocessor-controlled prosthetic knee and non-microprocessor control prosthetic knees: a preliminary study of energy expenditure, obstacle course performance, and quality of life survey. Prosthet Orthot Int 2007; 31(1):51-61.
- Kaufman KR, Levine JA, Brey RH et al. Gait and balance of transfemoral amputees using passive mechanical and microprocessor-controlled prosthetic knees. Gait Posture 2007; 26(4):489-93.
- Kaufman KR, Levine JA, Brey RH et al. Energy expenditure and activity of transfemoral amputees using mechanical and microprocessor-controlled prosthetic knees. Arch Phys Med Rehabil 2008; 89(7):1380-5.
- Bionic Technology - Proprio Foot, Walk Your Way. Ossur. 2002-2008. Available at www.ossur.com (Accessed 2008 September 4).
- LCD for Lower Limb Prostheses (L11464). Available at http://www.medicarenhic.com (Accessed 2009 January).
- Hafner BJ, Smith DG. Differences in function and safety between Medicare Functional Classification Level-2 and -3 transfemoral amputees and influence of prosthetic knee joint control. J Rehabil Res Dev 2009; 46(3):417-33.
- Alimusaj M, Fradet L, Braatz F et al. Kinematics and kinetics with an adaptive ankle foot system during stair ambulation of transtibial amputees. Gait Posture 2009; 30(3):356-63.
- Au S, Berniker M, Herr H. Powered ankle-foot prosthesis to assist level-ground and stair-descent gaits. Neural Netw 2008; 21(4):654-66.
- Patient Indications: List of indications for the C-Leg and Compact. Otto Bock, U.S. Available at: http://www.ottobockus.com (Accessed January 2009).
- Hofstad CJ, van der Linde H, et al. There is not enough evidence to establish precise criteria for the prescription of prosthetic ankle-foot mechanisms in individuals with a lower limb amputation. Cochrane Summary. Published Online January 21, 2009.
- Fradet L, Alimusaj M, Braatz F et al. Biomechanical analysis of ramp ambulation of transtibial amputees with an adaptive ankle foot system. Gait Posture 2010; 32(2):191-8.
- Gailey RS, Gaunaurd I, Agrawal V et al. Application of self-report and performance-based outcome measures to determine functional differences between four categories of prosthetic feet. J Rehabil Res Dev 2012; 49(4):597-612.
- Ferris AE, Aldridge JM, Rabago CA et al. Evaluation of a powered ankle-foot prosthetic system during walking. Arch Phys Med Rehabil 2012; 93(11):1911-8.
- Herr HM, Grabowski AM. Bionic ankle-foot prosthesis normalizes walking gait for persons with leg amputation. Proc Biol Sci 2012; 279(1728):457-64.
- Mancinelli C, Patritti BL, Tropea P et al. Comparing a passive-elastic and a powered prosthesis in transtibial amputees. Conf Proc IEEE Eng Med Biol Soc 2011; 2011:8255-8.
- Agrawal V, Gailey R, et al. Influence of gait training and prosthetic foot category on external work symmetry during unilateral transtibial amputee gait. Prosthet Orthot Int. 2013 Oct; 37(5):396-403. Epub 2013 Jan 30.
- Endolite Êlan. Products, Êlan Description. http://www.endolite.com (Accessed November 11, 2013.
- Microprocessor-Controlled Prosthetic Knees. Chicago, Illinois: Blue Cross Blue Shield Association Medical Policy Reference Manual (2013 March) Durable Medical Equipment 1.04.05.
||New 2013 BCBSMT medical policy.|
||Document updated with literature review. No changes to Coverage. “Êlan® (Endolite)” was added as an example of a microprocessor-controlled foot/ankle.|