Clinical UM Guideline

This document addresses the use of microprocessor controlled lower limb prostheses including, but not limited to, knee prostheses (such as the Blatchford Intelligent Prosthesis^®, Ottobock C-Leg^® device, the Genium^™ Bionic Prosthetic System, the Genium^™ X2^® and X₃^® devices, and the Ossur Rheo Knee^®) and foot-ankle prostheses (such as the Blatchford élan foot, Proprio Foot^®, and the emPOWER Ankle).

Note: For additional information regarding lower limb prosthesis, please see:

• CG-DME-13 Lower Limb Prosthesis

Medically Necessary:

1. Microprocessor controlled knee prostheses are considered medically necessary for individuals with transfemoral (above knee) and knee disarticulation amputations when all of the criteria set forth in (A) and (B) below have been met:
   1. Selection criteria:
      1. Individual has adequate cardiovascular reserve and cognitive learning ability to master the higher level technology; and
      2. Individual has a functional K-Level 3 or above; and
      3. The provider has documented that there is a reasonable likelihood of better mobility or stability with the device instead of a mechanical knee prosthesis; and
      4. There is documented need for ambulation in situations where the device will provide benefit (for example, regular need to ascend/descend stairs, traverse uneven surfaces or ambulate for long distances [generally 400 yards or greater cumulatively]);
         and
   2. Documentation and performance criteria:
      1. Complete multidisciplinary assessment of individual including an evaluation by a trained prosthetic clinician. The assessment must objectively document that all of the above selection criteria have been evaluated and met.
2. Microprocessor controlled foot or ankle systems are considered medically necessary for individuals with transtibial amputation when all of the criteria set forth in (A) and (B) below have been met:
   1. Selection criteria:
      1. Individual has adequate cardiovascular reserve and cognitive learning ability to master the higher level technology; and
      2. Individual has a functional K-Level 3 or above; and
      3. The provider has documented that there is a reasonable likelihood of better mobility or stability with the device instead of a mechanical foot or ankle prosthesis; and
      4. There is documented need for ambulation in situations where the device will provide benefit (for example, regular need to ascend/descend stairs, traverse uneven surfaces or ambulate for long distances [generally 400 yards or greater cumulatively]);
         and
   2. Documentation and performance criteria:
      1. Complete multidisciplinary assessment of individual including an evaluation by a trained prosthetic clinician. The assessment must objectively document that all of the above selection criteria have been evaluated and met.

Use of both a microprocessor controlled knee prosthesis and microprocessor controlled foot-ankle prosthesis simultaneously for the same individual, either for the same limb or for different limbs, is considered medically necessary when the applicable criteria for knee prosthesis and foot-ankle prosthesis above have both been met.

Repairs and replacements of a microprocessor controlled lower extremity prosthetic devices are considered medically necessary when:

1. Needed for normal wear or accidental damage; or
2. The changes in the individual’s condition warrant additional or different equipment, based on clinical documentation.

Not Medically Necessary:

Microprocessor controlled lower limb (knee/foot/ankle) prostheses are considered not medically necessary in all other cases, including when the criteria above have not been met, including for individuals with a functional K-Level 2 or below.

Repairs and replacements of a microprocessor controlled lower extremity prosthetic devices are considered not medically necessary when the criteria above have not been met.

Microprocessor controlled foot-ankle prostheses with power assistance, which includes any type of motor, are considered not medically necessary for all indications.

The following codes for treatments and procedures applicable to this guideline 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.

Knee 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 a situation indicated in the Clinical Indications section as not medically necessary.

Ankle/Foot 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 a situation indicated in the Clinical Indications section as not medically necessary.

When services are also Not Medically Necessary:

Repair
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.

Prostheses are devices that are used to replace or compensate for the absence of a body part. Such absence may be present at birth or due to amputation as the result of illness or trauma. Prosthetic devices have been used to replace body parts from individual fingers to entire limbs. Additionally, prostheses may include replacements for other body parts including breasts, eyes, and teeth. There are a wide variety of prostheses for the replacement of limbs made from various materials using a wide range of technologies.

The functional ability level of individuals with missing lower limbs is commonly rated via the use of the Medicare Functional Classification Level (MFCL), also known as K-Levels or Functional Levels (Centers for Medicare & Medicaid Services, 2017). The system is used to stratify individuals based on their ability to ambulate and function in various conditions. Additionally, K-Levels are commonly used to guide the appropriateness of specific types of lower limb prostheses. Provided below are definitions of these levels. Please note that within the functional classification hierarchy, individuals with bilateral amputations 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.

For prostheses used to replace lower limbs where the leg is missing from the knee or above, there is a need for a device to replace the normal function of the knee. In people with intact legs, the knee naturally and automatically adjusts its action to the speed and stride of the person. Conventional prosthetic legs use a pneumatic or hydraulic return mechanism to mimic the natural pendulum action of the knee. This mechanism is usually set by a prosthetist to work at the individual’s normal walking speed and does not allow any room for variation in speed. Changes in an individual’s walking speed require the individual to compensate for any delay in knee action through a variety of means including altering stride length and body position, among others. Such maneuvers lead to an abnormal gait and require extra effort and concentration for what is normally an unconscious act.

Microprocessor controlled lower limb prostheses for individuals with transfemoral amputations use computer-controlled mechanisms to detect step time and alter prosthetic function such as knee extension level to suit walking speed or angle of the terrain. More advanced models, such as the Ottobock C-Leg (Duderstadt, Germany), 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. The claimed advantages of a computerized leg prosthesis include a decreased level of effort in walking, improved symmetry of movement between legs leading to more natural movement, and the avoidance of falls.

For individuals who have lost a limb below the knee, there is a need for a device to replace the function of the ankle and foot. Stair ambulation is limited in the individuals with transtibial amputations due to the neutral and fixed ankle position which exists in traditional prosthetic ankles. Under study are newer prosthetic ankles which adjust the foot-ankle angle during the swing phase using sensor and microprocessor technologies to identify sloping gradients and the ascent or descent of stairs after the first step. Users can place the foot fully on a step when climbing or descending stairs and it will automatically adapt the ankle position to enable the next step. On ramp ascent and descent, adaptation begins on the second step and the device makes small adjustments until it reaches the degree of slope of the ramp. The Proprio Foot (Össur, Reykjavík, Iceland) is one such “quasi-passive” device. The device is passive since no power is generated through the ankle in stance. The device is also said to be designed to dorsiflex, or bring the toes closer to the shin, during the swing phase to improve ground clearance, improve gait symmetry and reduce the likelihood of falls. Other claims include the device’s ability to assist in standing from a seated position and plantar (bottom of the foot) flexion when kneeling, sitting and lying down. Early pilot studies suggest that both during stair ascent and descent, the Proprio Foot improves knee flexion kinematics. The weight of the Proprio Foot device is more than twice the weight of a conventional ankle-foot prosthetic such as the LP Vari-Flex (995g versus 405g). Concern has been raised that because of its weight, the Proprio Foot might not benefit individuals with amputations with limited endurance and knee musculature.

Also under study are active prosthetic ankle prostheses which do generate power during the ankle stance. Early results are said to be promising, but these devices are bulky and of considerable weight due to the motor and batteries needed to generate power.

The FDA classified the Proprio Foot as a Class I device and the PowerFoot (Ottobock, Duderstadt, Germany) as a class II device, both exempt from requirements for pre-market notification by submission and FDA review of a 510(k) clearance. This is based on the level of active assistance provided and the perceived risk associated with these devices.

Microprocessor Controlled Knee Prosthesis

Microprocessor controlled knee prosthesis have been clinically available and widely used for some time. While the studies addressing these devices are often relatively underpowered and may not be randomized, the clinical benefits of the devices have been well established.

According to the Veterans Affairs/Department of Defense (VA/DoD) Clinical Practice Guideline for Rehabilitation of Individuals with Lower Limb Amputation (2017), it is suggested that a microprocessor-controlled knee unit should be offered over a non-microprocessor knee unit for ambulation to reduce risk of falls and to maximize the satisfaction of the individual. The guideline also stated the following:

Access to early weight-bearing prostheses has expanded through the introduction of several different prefabricated systems that are commercially available. More research is required to further delineate the risks and benefits associated with this intervention as well as to further determine the differences between articulated and non-articulated devices.

Stevens and Wurdeman (2019) published recommendations for the selection of individuals with unilateral transfemoral amputations. In this document they proposed the following recommendations:

Recommendation 1. Fluid knee benefits and indications: Knees with hydraulic or pneumatic swing resistance are indicated for active walkers, permitting increased walking comfort, speed, and symmetry.
Recommendation 2. Microprocessor knee benefits: Compared with nonmicroprocessor knees: a) With respect to self-report indices and measures, microprocessor knees are indicated to reduce stumbles, falls, and associated frustrations as well as the cognitive demands of ambulation. b) With respect to self-report indices and measures, microprocessor knees are indicated to increase confidence while walking, self-reported mobility, satisfaction, well-being, and quality of life. c) With respect to physical performance indices and measures, microprocessor knees are indicated to increase self-selected walking speed, walking speed on uneven terrain, and metabolic efficiency during gait.
Recommendation 3. Microprocessor knee equivalence: Given the comparable values observed with the use of microprocessor and nonmicroprocessor knees with regard to daily step counts, temporal and spatial gait symmetry, self-reported general health, and total costs of prosthetic rehabilitation, these parameters may not be primary indications in prosthetic knee joint selection.
Recommendation 4. Microprocessor knees for limited community ambulators: Among limited community ambulators, microprocessor knees are indicated to enable increases in level ground walking speed and walking speed on uneven terrain while substantially reducing uncontrolled falls and increasing both measured and perceived balance.

Microprocessor controlled knee prostheses are appropriate for individuals who meet criteria for fitness, health and daily utilization expectations. The currently available scientific evidence demonstrates benefits for individuals with a K-3 or K-4 functional level (Bell, 2016; Bellmann, 2012; Bellmann, 2018; Burnfield, 2012; Eberly, 2014; Hafner, 2007 and 2009; Hahn, 2016; Hasenoehrl, 2018; Highsmith, 2014; Jayaraman, 2021; Kaufman, 2018; Palumbo,2022; Prinsen, 2015 and 2017; Theeven, 2011, 2012 and 2013; Thibaut, 2021; Thiele, 2019; Williams, 2006; Wong; 2015; Wurdeman, 2018 and 2023). Such individuals are capable of performing physical tasks requiring significant strength, coordination, aerobic fitness, and cognitive capacity. These tasks include ambulation at variable cadences and for extended distances or time periods (for example, 400 yards or more), or the ability to traverse challenging environmental barriers (for example, stairs). They may also be capable of participating in athletic activities involving high impact or aerobic needs. As such, the use of microprocessor controlled lower limb prostheses may be appropriate for users who have the physical capacity for such activities on a regular basis. Alternatively, the data does not show significant benefits of microprocessor controlled lower limb prostheses for individuals who do not have high-level physical needs, such as those with K-1 or K-2 functional levels, or those who do not have a demand for extensive physical activity. The benefits of the marginal improvements in functional capacity provided by microprocessor controlled lower limb devices, such as reduced oxygen consumption, improving walking speed, and safety when ambulating in more challenging environments, are not clear for individuals at lower function levels. Furthermore, for those individuals who do have K-3 or K-4 functional levels, but do not encounter a regular need to ambulate for long distances over significant environmental challenges beyond what may be encountered in the average home or workplace, there is little benefit provided from the use of microprocessor controlled lower limb devices. In addition, these devices require substantial training to allow for faster than normal walking speed. A user should have adequate cognitive learning ability to master the higher level technology.

The evidence-based literature reviewed for the microprocessor controlled lower limb prosthesis evaluated actual and functional outcomes. The evidence includes a number of participant comparisons of the microprocessor controlled knee versus non-microprocessor controlled knee joints. Many of the studies reflect an objective improvement in function in regard to some outcome measures when the microprocessor controlled knee is used as compared to a more traditional non-microprocessor controlled knee. In addition, some of the literature reviewed revealed the microprocessor controlled knee prosthesis demonstrated a significant improvement with individuals in such areas of SAI scores, time to descend scores and improvement in function. Improvement of the individual’s performance within these areas can potentially reduce adverse events. The choice of the most appropriate prosthetic design will be impacted by the individual’s underlying activity level, improved functional mobility and other factors that would improve walking performance.

Microprocessor Controlled Foot and Ankle Prosthesis

Microprocessor controlled foot and ankle prosthesis are devices that involve the use of microprocessors to control the position and action of the prosthetic ankle joint to mimic natural joint resistance and motion. This process has been proposed to result in more natural joint stability while standing and walking. Currently, two types of microprocessor-controlled foot-ankle prosthetic devices are discussed in the peer-reviewed literature, those without powered propulsion push-off at the end of the Stance Phase of the gait cycle and those with powered propulsion push-off at the end of the Stance Phase of the gait cycle. Examples of the former are the Proprio Foot and Blatchford (Basingstoke, United Kingdom) élan foot and élan footIC devices, while the latter includes emPOWER Ankle devices.

The VA/DOD Clinical Practice Guideline for Rehabilitation of individuals with Lower Limb Amputation (2017) suggest 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. The guideline reports that 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. The individual’s desired outcome, goals, and the compatibility of the entire prosthetic system should also be a consideration when prescribing prosthetic components.

Microprocessor Controlled Foot-Ankle Prosthesis Without Powered Propulsion

These types of prostheses do not use electric power to augment push-off at the end of the Stance Phase of the gait cycle. They use an inter-step accommodation strategy which means that it only makes adjustments to the ankle when the foot is in the Swing Phase of the gait cycle. Furthermore, they do not make adjustments on each step, but instead require multiple steps to adjust, depending on the terrain.

The available published, peer-reviewed evidence addressing the use of microprocessor controlled foot-ankle prosthesis without powered propulsion includes multiple studies that have reported the benefits of these types of devices (Agrawal, 2013 and 2015; Alimusaj, 2009; Colas-Ribas, 2022; Darter, 2014; Delussu; 2013; Fradet, 2010; Gailey, 2012; Rosenblat, 2014; Wolf, 2009). Reported benefits include improved physiologic kinematics, joint kinetics, stump pressures, energy expenditure, interlimb symmetry, walking speed, and the ability to manage stairs, slopes, and varied terrain.

Combined Microprocessor Controlled Knee And Microprocessor Controlled Foot-Ankle Prosthesis

The use of both microprocessor-controlled knee prosthesis and microprocessor-controlled foot-ankle prosthesis at the same time for the same limb has been proposed for certain individuals who may benefit from the use of both devices simultaneously. Such prosthesis may consist of two separate devices combined into one system by a provider or may come from the manufacturer as a single unit (e.g., Ossur Symbionic^® Leg 3, Blatchford LiNX^® Limb System). Use of such combined devices is rare and usually limited to high functioning individuals who are able to manage the weight of such devices.

Foot-Ankle Prosthesis with Powered Propulsion

These types of prosthetic devices offer powered propulsion of the foot by emulating the function and power of missing muscles and tendons of the ankle and foot. In addition, these devices automatically adjusts foot stiffness in the heel strike portion of the Stance Phase which has been proposed to optimize shock absorption and foot loading.

In 2007, the VA Office of Research and Development collaborated with researchers at MIT and Brown University to introduce a powered ankle-foot prosthesis that uses tendon-like springs and an electric motor to move users forward. According to the VA, studies have shown that individuals using the powered ankle-foot expend less energy while walking, have better balance, and walk 15 percent faster. The device originally sold as the BiOM Ankle and is now marketed as the EmpOWER Ankle by Ottobock.

Herr (2011) conducted a study investigating the metabolic energy costs, preferred velocities, and biomechanical patterns in 7 individuals with unilateral transtibial amputations and 7 control individuals without amputations. The experimental group was tested using a BiOM and their own passive-elastic prosthesis. The authors reported that compared with the passive-elastic prosthesis, the bionic prosthesis decreased metabolic cost by 8%, increased trailing prosthetic leg mechanical work by 57% and decreased the leading biological leg mechanical work by 10%, on average, across walking velocities of 0.75-1.75 m s^-1. Use of the bionic prosthesis also increased preferred walking velocity by 23%. They concluded that the bionic prosthesis resulted in metabolic energy costs, preferred walking velocities and biomechanical patterns that were not significantly different from people without an amputation. However, due to the small study size it is unclear whether or not these results would be seen in the general population.

Ferris (2012) reported on the results of a prospective study involving 11 participants with transtibial amputations and 11 healthy controls. All participants participated in a battery of tests including a 10-meter forward run, a 5-meter side-shuffle to right, a 10-meter side shuffle to left, a 5-meter side-shuffle to right, a 10-meter backward run, a Four Square Step Test, and hill and stair assessments. Participants in the amputation group conducted the tests first with an energy-storing and returning (ESR) prosthesis and then with the BiOM prosthesis. The authors reported that the BiOM prosthesis ankle range of motion was significantly larger (approximately 30%) than that of the ESR limb. However, both devices demonstrated significantly less ankle range of motion than the intact limbs. The BiOM prosthesis was reported to have generated significantly greater peak ankle power than control (35%) and ESR (approximately 125%) limbs, resulting in the BiOM limb absorbing twice the peak knee power observed in the control and intact limbs. The BiOM’s limb peak hip power generation was approximately 45% greater at preswing than that of the intact limb. No significant differences were reported in walking velocity between the ESR and BiOM groups. The authors concluded that use of the BiOM appeared to increase compensatory strategies at proximal joints. The clinical impact of these benefits is unclear.

Gates (2013) reported a controlled study involving 11 participants with transtibial amputation who were asked to participate in two data collection trials involving different walking speeds across a loose rock surface using their standard ESR prosthesis and then the BiOM device. Participants using the BiOM had a 10% faster self-selected walking speed compared to when using the ESR device (1.16 m/s vs. 1.05 m/s; p=0.031). Ankle plantarflexion was also increased on their prosthetic limb throughout the gait cycle when wearing BiOM vs ESR devices, especially during push-off (p<0.001). A small (< 3°), but statistically significant decrease in knee flexion during early stance was noted with the BiOM device (p=0.045). No significant differences in kinematics of the knee and hip were reported, but participants had decreased medial–lateral motion of their center of mass when wearing the BiOM prosthesis (p=0.020). The authors concluded that use of the BiOM did not significantly alter their proximal joint kinematics when used on an irregular surface.

Grabowski (2013) reported the results of a controlled trial involving 14 participants, 7 with transtibial amputations and 7 healthy controls, subject to level ground walking trials at 0.75, 1.00, 1.25, 1.50, and 1.75 m/s. The amputation participants conducted their walking trials with their standard prosthesis and then with the BiOM prosthesis. The investigators were interested in how physical performance measures of the intact limb of the amputation group participants were impacted by the use of the BiOM prosthesis compared to the standard device and healthy controls. They reported that the use of the BiOM significantly decreased intact limb peak resultant forces and first peak knee external adduction moments. Loading rates were not significantly different between prosthetic feet. They concluded that use of the BiOM prosthesis could reduce the risk of comorbidities such as knee osteoarthritis. However, no long term data have yet been published addressing that proposition.

Gardinier (2018) reported the results of a controlled trial involving 10 participants with transtibial amputations and 10 healthy participants. Testing included an 8-meter walk test at self-selected speeds and an 8-minute treadmill test. Walking speed was measured during the former and metabolic rate during the latter. Amputation group participants were randomly assigned to undergo testing first with either the BiOM or their standard prosthetic device. The authors reported no significant differences between either of the prosthetic groups with regard to walking speeds or metabolic costs. This study did not demonstrate significant benefits with the use of the BiOM.

Kim (2021) reported the results of a unblinded, randomized, controlled, cross-over study involving 12 participants with unilateral transtibial amputations assigned to undergo a battery of tests with both their prescribed, unpowered prosthesis and the BiOM device. The BiOM was used first in the trial by 7 participants and the unpowered device by 5 participants, before crossover. Participants used the devices for 2 weeks while wearing activity monitors and laboratory testing was conducted to evaluate metabolism and QOL. Ten participants completed the study, 9 whom were K3 ambulators and the tenth was a K4 ambulator. No differences between groups were reported with regard to fixed treadmill speed and self-selected walking speeds with the unpowered device (p=0.435) or BiOM (p=0.794), self-selected walking speed in the lab (p=0.452) or in daily life (p=0.226), metabolic cost of transport (p=0.585), or daily step count away from home (p=0.452). Results on the Prosthesis Evaluation Questionnaire indicated significantly less social burden with the BiOM (p=0.043). On SF-36 results, no significant differences were reported on the physical or mental components (p=0.48 and p=0.37, respectively). The results of this study indicate no significant overall benefits to the use of the BiOM device.

Evidence in the published peer-reviewed literature for the use of a microprocessor controlled foot or ankle prosthesis is comprised of underpowered non-randomized studies, which do not fully address functional or quality of life benefits for individuals with a functional K-3 level or above. However, consideration of clinical input and other relevant factors supports that use of these devices without powered propulsion in individuals with functional K-3 level or above is consistent with generally accepted standards of medical practice. Additional evidence is needed to better evaluate devices with a power propulsion to fully evaluate whether there are clinical presentations where that functionality improves outcomes over other devices.

Other information:

In 2018 the Agency for Healthcare Research and Quality (AHRQ) published a comparative effectiveness review of lower limb prostheses. In that document they concluded the following:

Overall, studies that investigated subgroup effects did not identify participant characteristics that predict which lower limb amputees would benefit most or least from a given LLP component or configuration. Based on the methodology used to assess strength of evidence, the studies warrant a low strength of evidence that patient characteristics evaluated in the studies do not predict which patients would benefit most or least from a given LLP component or configuration (Table E). Although one large study attempted to develop a model to predict success with microprocessor knees, the study did not use a validated outcome and had several methodological and analytic issues. It, therefore, provided insufficient additional evidence regarding who would be more likely or less likely to benefit from a microprocessor knee. An additional issue across almost all studies was that study participants were in general not likely to be representative of the Medicare population, being both mostly young and with amputations due to trauma, with relatively few people with dysvascular disease.

Computerized leg prosthesis: A prosthetic device for individuals with some degree of leg amputation which uses a computer microprocessor to adapt prosthetic function to environmental conditions that impact locomotion.

Foot-Ankle Prosthesis Without Powered Propulsion: A prosthetic device that does not use electric power to augment push-off at the end of the Stance Phase of the gait cycle.

Foot-Ankle Prosthesis with Powered Propulsion: A prosthetic device that offers a powered push-off feature by emulating the function and power of lost muscles and tendons. The device automatically adjusts its foot stiffness in the heel strike portion of the Stance Phase which ensures optimum shock absorption and foot loading.

Kinematics: A study of motion without regard to the forces present; mathematical methods to describe motion.

Multidisciplinary assessment: An evaluation process that may involve professionals from multiple medical specialties, including any of physiatrists, physical or occupational therapists, internal medicine, cardiologists, behavioral health, and others.

Prosthesis: For the purposes of this document, a device used to replace or compensate for the absence of a limb. Prostheses may be artificial replacements for a wide variety of body parts.

Peer Reviewed Publications:

1. Agrawal V, Gailey RS, Gaunaurd IA, et al. Comparison between microprocessor-controlled ankle/foot and conventional prosthetic feet during stair negotiation in people with unilateral transtibial amputation. J Rehabil Res Dev. 2013; 50(7):941-950.
2. Agrawal V, Gailey RS, Gaunaurd IA, et al. Comparison of four different categories of prosthetic feet during ramp ambulation in unilateral transtibial amputees. Prosthet Orthot Int. 2015; 39(5):380-389.
3. 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):356-363.
4. Bell EM, Pruziner AL, Wilken JM, Wolf EJ. Performance of conventional and X2^® prosthetic knees during slope descent. Clin Biomech (Bristol, Avon). 2016; 33:26-31.
5. Bellmann M, Köhler TM, Schmalz T. Comparative biomechanical evaluation of two technologically different microprocessor-controlled prosthetic knee joints in safety-relevant daily-life situations. Biomed Tech (Berl). 2019; 64(4):407-420.
6. Bellmann M, Schmalz T, Ludwigs E, Blumentritt S. Immediate effects of a new microprocessor-controlled prosthetic knee joint: a comparative biomechanical evaluation. Arch Phys Med Rehabil. 2012; 93(3):541-549.
7. Burnfield JM, Eberly VJ, Gronely JK, et al. Impact of stance phase microprocessor-controlled knee prosthesis on ramp negotiation and community walking function in K2 level transfemoral amputees. Prosthet Orthot Int. 2012; 36(1):95-104.
8. Chin T, Machida K, Sawamura S, et al. Comparison of different microprocessor controlled knee joints on the energy consumption during walking in trans-femoral amputees: intelligent knee prosthesis (IP) versus C-leg. Prosthet Orthot Int. 2006; 30(1):73-80.
9. Chin T, Sawamura S, Shiba R, et al. Effect of an Intelligent Prosthesis (IP) on the walking ability of young transfemoral amputees: comparison of IP users with able-bodied people. Am J Phys Med Rehabil. 2003; 82(6):447-451.
10. Colas-Ribas C, Martinet N, Audat G, et al. Effects of a microprocessor-controlled ankle-foot unit on energy expenditure, quality of life, and postural stability in persons with transtibial amputation: An unblinded, randomized, controlled, cross-over study. Prosthet Orthot Int. 2022; 46(6):541-548.
11. Darter BJ, Wilken JM. Energetic consequences of using a prosthesis with adaptive ankle motion during slope walking in persons with a transtibial amputation. Prosthet Orthot Int. 2014; 38(1):5-11.
12. 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.
13. Delussu AS, Brunelli S, Paradisi F, et al. Assessment of the effects of carbon fiber and bionic foot during overground and treadmill walking in transtibial amputees. Gait Posture. 2013; 38(4):876-882.
14. Eberly VJ, Mulroy SJ, Gronley JK, et al. Impact of a stance phase microprocessor-controlled knee prosthesis on level walking in lower functioning individuals with a transfemoral amputation. Prosthet Orthot Int. 2014; 38(6):447-455.
15. Ferris AE, Aldridge JM, Rábago CA, Wilken JM. Evaluation of a powered ankle-foot prosthetic system during walking. Arch Phys Med Rehabil. 2012; 93(11):1911-1918.
16. Fradet L, Alimusaj M, Braatz F, Wolf SI. Biomechanical analysis of ramp ambulation of transtibial amputees with an adaptive ankle foot system. Gait Posture. 2010; 32(2):191-198.
17. 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.
18. Gardinier ES, Kelly BM, Wensman J, Gates DH. A controlled clinical trial of a clinically-tuned powered ankle prosthesis in people with transtibial amputation. Clin Rehabil. 2018; 32(3):319-329.
19. Gates DH, Aldridge JM, Wilken JM. Kinematic comparison of walking on uneven ground using powered and unpowered prostheses. Clin Biomech (Bristol, Avon). 2013; 28(4):467-472.
20. Grabowski AM1, D'Andrea S. Effects of a powered ankle-foot prosthesis on kinetic loading of the unaffected leg during level-ground walking. J Neuroeng Rehabil. 2013; 10:49.
21. 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):417-433.
22. 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.
23. Hahn A, Lang M, Stuckart C. Analysis of clinically important factors on the performance of advanced hydraulic, microprocessor-controlled exo-prosthetic knee joints based on 899 trial fittings. Medicine (Baltimore). 2016; 95(45):e5386.
24. Hasenoehrl T, Schmalz T, Windhager R, et al. Safety and function of a prototype microprocessor-controlled knee prosthesis for low active transfemoral amputees switching from a mechanic knee prosthesis: a pilot study Disabil Rehabil Assist Technol. 2018; 13(2):157-165.
25. Herr HM, Grabowski AM. Bionic ankle-foot prosthesis normalizes walking gait for persons with leg amputation. Proc Biol Sci. 2012; 279(1728):457-464.
26. Highsmith MJ, Kahle JT, Shepard NT, Kaufman KR. The effect of the C-Leg knee prosthesis on sensory dependency and falls during sensory organization testing. Technol Innov. 2014; 2013(4):343-347.
27. Jayaraman C, Mummidisetty CK, Albert MV, et al. Using a microprocessor knee (C-Leg) with appropriate foot transitioned individuals with dysvascular transfemoral amputations to higher performance levels: a longitudinal randomized clinical trial. J Neuroeng Rehabil. 2021; 18(1):88.
28. 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):563-575.
29. Kahle JT, Highsmith MJ, Hubbard SL. Comparison of nonmicroprocessor knee mechanism versus C-Leg on Prosthesis Evaluation Questionnaire, stumbles, falls, walking tests, descent, and knee preference. J Rehabil Res Dev. 2008; 45(1):1-14.
30. 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):1380-1385.
31. 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):489-493.
32. Kim J, Wensman J, Colabianchi N, Gates DH. The influence of powered prostheses on user perspectives, metabolics, and activity: a randomized crossover trial. J Neuroeng Rehabil. 2021; Mar 16;18(1):49.
33. Klute GK, Berge JS, Orendurff MS, et al. Prosthetic intervention effects on activity of lower-extremity amputees. Arch Phys Med Rehabil. 2006; 87(5):717-722.
34. Mileusnic MP, Rettinger L, Highsmith MJ, et al. Benefits of the Genium microprocessor controlled prosthetic knee on ambulation, mobility activities of daily living and quality of life: a systematic literature review. Disabil Rehabil Assist Technol. 2021; 16(5):453-464.
35. Orendurff MS, Segal AD, Klute GK, et al. Gait efficiency using the C-leg. J Rehabil Res Dev. 2006; 43(2):239-246.
36. Palumbo P, Randi P, Moscato S, et al. Degree of safety against falls provided by 4 different prosthetic knee types in people with transfemoral amputation: a retrospective observational study. Phys Ther. 2022; 102(4):pzab310.
37. Prinsen EC, Nederhand MJ, Olsman J, Rietman JS. Influence of a user-adaptive prosthetic knee on quality of life, balance confidence, and measures of mobility: a randomised cross-over trial. Clin Rehabil. 2015; 29(6):581-591.
38. Prinsen EC, Nederhand MJ, Sveinsdóttir HS, et al. The influence of a user-adaptive prosthetic knee across varying walking speeds: a randomized cross-over trial. Gait Posture. 2017; 51:254-260.
39. Rosenblatt NJ, Bauer A, Rotter D, Grabiner MD. Active dorsiflexing prostheses may reduce trip-related fall risk in people with transtibial amputation. J Rehabil Res Dev. 2014; 51(8):1229-1242.
40. Schmalz T, Blumentritt S, Jarasch R. Energy expenditure and biomechanical characteristics of lower limb amputee gait: the influence of prosthetic alignment and different prosthetic components. Gait Posture. 2002; 16(3):255-263.
41. Segal AD, Orendurff MS, Klute GK, et al. Kinematic and kinetic comparisons of transfemoral amputee gait using C-Leg and Mauch SNS prosthetic knees. J Rehabil Res Dev. 2006; 43(7):857-870.
42. Seymour R, Engbretson B, Kott K, et al. Comparison between the C-leg 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.
43. Taylor MB, Clark E, Offord EA, Baxter C. A comparison of energy expenditure by a high level trans-femoral amputee using the Intelligent Prosthesis and conventionally damped prosthetic limbs. Prosthet Orthot Int. 1996; 20(2):116-121.
44. Theeven PJ, Hemmen B, Brink PR, et al. Measures and procedures utilized to determine the added value of microprocessor-controlled prosthetic knee joints: a systematic review. BMC Musculoskelet Disord. 2013; 14: 333.
45. Theeven PJ, Hemmen B, Geers RP, et al. Influence of advanced prosthetic knee joints on perceived performance and everyday life activity level of low-functional persons with a transfemoral amputation or knee disarticulation. J Rehabil Med. 2012; 44(5):454-461.
46. Theeven P, Hemmen B, Rings F, et al. Functional added value of microprocessor-controlled knee joints in daily life performance of Medicare Functional Classification Level-2 amputees. J Rehabil Med. 2011; 43(10):906-915.
47. Thibaut A, Beaudart C, Maertens de Noordhout B, et al. Impact of microprocessor prosthetic knee on mobility and quality of life in patients with lower limb amputations: a systematic review of the literature. Eur J Phys Rehabil. Feb 11. Online ahead of print.
48. Thiele J, Schöllig C, Bellmann M, Kraft M. Designs and performance of three new microprocessor-controlled knee joints. Biomed Tech (Berl). 2019; 64(1):119-126.
49. 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):989-994.
50. Wolf SI, Alimusaj M, Fradet L, et al. Pressure characteristics at the stump/socket interface in transtibial amputees using an adaptive prosthetic foot. Clin Biomech (Bristol, Avon). 2009; 24(10):860-865.
51. Wong CK, Rheinstein J, Stern MA. Benefits for adults with transfemoral amputations and peripheral artery disease using microprocessor compared with nonmicroprocessor prosthetic knees. Am J Phys Med Rehabil. 2015; 94(10):804-810.
52. Wurdeman SR, Miller TA, Stevens PM, Campbell JH. Stability and falls evaluations in amputees (SAFE-AMP 1): Microprocessor knee technology reduces odds of incurring an injurious fall for individuals with diabetic/dysvascular amputation. Assist Technol. 2023; 35(3):205-210.
53. Wurdeman SR, Stevens PM, Campbell JH. Mobility analysis of amputees (MAAT 3): matching individuals based on comorbid health reveals improved function for above-knee prosthesis users with microprocessor knee technology. Assist Technol. 2019; 13;6:205566831882078.

Government Agency, Medical Society, and Other Authoritative Publications:

1. Agency for Healthcare Research and Quality (AHRQ). Comparative Effectiveness Review. Number 213. Lower limb prostheses: measurement instruments, comparison of component effects by subgroups, and long-term outcomes. Published September 6, 2018. Available at: https://effectivehealthcare.ahrq.gov/sites/default/files/related_files/cer-213-lower-limb-protheses-evidence-summary.pdf?_gl=1*12ct9qw*_ga*MzY4MDg1OTY4LjE3MTY5ODg5Mzk.*_ga_45NDTD15CJ*MTcxNzA5Njg2MS4zLjEuMTcxNzA5NzgxNS41Ny4wLjA. Accessed on July 24, 2024.
2. 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 on July 24, 2024.
3. Stevens PM, Wurdeman SR. Prosthetic knee selection for individuals with unilateral transfemoral amputation: a clinical practice guideline. J Prosthet Orthot. 2019; 31(1):2-8.
4. U.S Department of Veterans Affairs. Department of Defense. VA/DoD clinical practice guideline for rehabilitation of individuals with lower limb amputation. September 2017. Available at: https://www.healthquality.va.gov/guidelines/Rehab/amp/VADoDLLACPG092817.pdf. Accessed July 24, 2024.
5. U.S. Department of Veterans Affairs. Office of Research & Development. VA research on prosthetic/limb loss. Last updated 1/15/21. Available at: https://www.research.va.gov/topics/prosthetics.cfm. Accessed on July 24, 2024.
6. Washington State Health Care Authority, Health Technology Assessment Program. Microprocessor-controlled lower limb prosthetics. October 12, 2011. Available at: http://www.hca.wa.gov/assets/program/mc_lower_prosthetic_final_report%5B1%5D.pdf. Accessed on July 24, 2024.

Above Knee Prosthetics
Adaptive Prosthesis
BiOM
Blatchford élan foot
Blatchford élanIC foot
Blatchford LiNX Limb System
Blatchford SmartIP
Endolite élan foot
Endolite Intelligent Prosthesis^®
Endolite Orion3
Endolite Smart Adaptive knee
Endolite SmartIP
Freedom Innovations Plie Knee
Ossur Power Knee^™
Ossur Proprio Foot^®
Ossur Rheo Knee^®
Ossur Symbionic Leg
Otto Bock BionX EMemPOWER
Otto Bock C-Leg Compact
Otto Bock Genium^™ Bionic Prosthetic System
Otto Bock Genium^™ X2^® and X3^®
Otto Bock Kinnex Microprocessor Ankle/Foot System
Ottobock C-Leg 4
Ottobock C-Leg Compact
Ottobock Empower
Ottobock Kenevo
Ottobock Meridium
Ottobock Triton Ssmart aAnkle
PowerFoot BiOM
Proprio Foot^®
Proteor Kinnex 2.0 Foot-Ankle system
Proteor Kinnex Foot-Ankle system
Proteor Quattro Knee

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.

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