Loading...

    Explore
    • Policy Monitoring
    • Live Policy Feed
    • Billing Codes
    • Healthcare Providers
    • Health Insurance Payers
    • States
    • Service Lines
    • Taxonomy Codes
    Lookup tools
    • Billing Code Lookup
    • CPT Modifier Lookup
    • Provider Taxonomy Code Lookup
    • Healthcare Provider & Facility Lookup
    • Health Insurance Payer Lookup
    • Payer Contact Directory

    Policy & Benchmark Tools

    • Prior Authorization Lookup
    • Coverage Criteria Lookup
    • Timely Filing Lookup
    • Billing Code Reimbursement Rates
    • Payer Comparison Dashboard
    • Facility Comparison Dashboard
    • All tools

    Company

    • About OpenPayer
    • Data Sources
    • Trek Health
    OpenPayerby Trek Health
    LinkedInYouTube

    © 2026 Trek Health. All rights reserved.

    OpenPayer is built and maintained by Trek Health.

    v1.0.31
    OpenPayerPolicy UpdatesProsthetics & OrthoticsAetna Lower Limb Prostheses Coverage & Prior Auth …
    Ask Trek AI about this page

    OpenPayer is powered by Trek Health's payer performance platform. Trek continuously ingests, validates, and normalizes Transparency in Coverage data alongside payer policies and other commercial payer data to create a structured payer intelligence foundation. OpenPayer uses this foundation to deliver personalized search results, dynamically generated policy pages, and tailored policy monitoring based on each user's payers, specialties, billing codes, and areas of interest. The same intelligence powers broader payer performance workflows, including reimbursement benchmarking, contract evaluation, payer negotiations, and financial decision-making.

    CurrentAetnaPolicy 0578

    Lower Limb Prostheses

    Customize your policy alerts

    Sign up for Aetna Policy 0578 alerts

    Get alerted when Policy 0578 changes without checking for updates manually.

    Monitor payer policy activity

    Receive email alerts as soon as relevant payer policies are published or updated.

    Clinical policy governing medical necessity, coverage, coding, and exclusions for lower limb prosthetic devices and related components for Aetna members.

    Policy Summary
    PayerAetna
    PolicyLower Limb Prostheses
    Policy CodePolicy 0578
    Change TypeNo material changes noted
    Effective DateNov 13, 2001
    Last ReviewFeb 19, 2024
    Next Review DateJun 8, 2023
    Key ActionCommunicate a completed Standard Written Order (SWO) to the supplier before submitting a claim; claims billed without an SWO will be denied.
    SourceLink
    POLICY UPDATE CHANGES

    No material clinical or coverage changes in this revision.

    K-levels 0-4functional classification referenced
    K3-K4candidates referenced
    2 socketstest sockets limit
    32%osseointegration infection rate
    3x/week ~8 wksexoskeleton training dose

    Coverage Criteria for Lower Limb Prostheses

    Prosthetic foot technologies — evidence summary

    Prosthetic foot technologies — evidence summary: summarize clinical evidence, limitations, and policy translations for microprocessor-controlled feet, energy-return (ESAR) and novel linkage feet, and other advanced foot systems.

    1. Microprocessor-controlled feet (e.g., Proprio Foot, PowerFoot BiOM, iWalk BiOM, iWalk, Proprio)
    2. Evidence for microprocessor-controlled feet is limited and largely based on small studies that measure short-term kinematic or surrogate outcomes rather than robust patient-centered functional outcomes (e.g., daily step counts, fall rates, energy expenditure, long-term QoL). Key studies show improved ankle motion and some normalization of ankle power (BiOM) and improved inter-limb symmetry on stair ascent (Proprio), but findings are preliminary and inconsistent across tasks such as stair descent.
    3. A small randomized crossover trial and several nonrandomized studies (e.g., Highsmith et al., 2016 comparing Genium vs C-Leg for transfemoral amputees) suggest certain microprocessor-controlled knee/foot systems can improve stair performance, multi-directional stepping, some ADL domains, and user preference in selected community ambulators, but generalizability is limited.
    Policy Summary
    PayerAetna
    PolicyLower Limb Prostheses
    Policy CodePolicy 0578
    Change TypeNo material changes noted
    Effective DateNov 13, 2001
    Last ReviewFeb 19, 2024
    Next Review DateJun 8, 2023
    Key ActionCommunicate a completed Standard Written Order (SWO) to the supplier before submitting a claim; claims billed without an SWO will be denied.
    SourceLink
    On This Page
    Coverage Criteria for Lower Limb ProsthesesCoding and Billing GuidanceProvider Requirements, Prior Authorization, and DocumentationBackground and Evidence SummaryDefinitions and Key Terms
    4. Energy-storing-and-return (ESAR) and novel linkage feet (e.g., Pro-Flex, Vari-Flex, new linkage systems) demonstrate increased prosthetic ankle power and range of motion, with some data indicating reduced contralateral limb loading and potential to transfer more propulsive energy to whole-body center-of-mass propulsion. Sample sizes are small and clinical implications (e.g., osteoarthritis risk reduction) remain uncertain.
    5. Bionic / powered feet (e.g., BiOM, iWalk PowerFoot) have shown restoration of ankle power and increased ankle motion in laboratory and small clinical samples, but do not consistently reduce compensatory hip strategies and evidence of meaningful improvements in community ambulation, fall reduction, energy expenditure, or long-term outcomes is inadequate.
    6. Overall evidence limitations: studies are often small, nonrandomized, short-term, industry-funded, and emphasize intermediate/biomechanical outcomes. Systematic reviews (including Washington State HTA) concluded there is insufficient evidence to draw definitive conclusions about comparative effectiveness, safety, or cost-effectiveness for microprocessor-controlled foot devices.
    7. Policy translation: Given the limited and inconsistent evidence, coverage is generally reserved for members with documented K-level functional status consistent with device intent (typically K3 or above for microprocessor-controlled foot devices) when clinical documentation supports functional benefit and device fitting/training by qualified providers. Devices lacking robust evidence or used for unsupported indications (e.g., gait management in spinal cord injury) are considered not covered or investigational per policy.
    paragraphs:[

    Coding and Billing Guidance

    HCPCS codes covered if selection criteria are metHCPCSCovered
    L5000 - L5782, L5785 - L5972, L5974 - L5988, L5999Lower limb prostheses (range).
    L5930Addition, endoskeletal system, high activity knee control frame [covered for members whose functional level is 4].
    L5940Addition, endoskeletal system, below knee, ultra-light material (titanium, carbon fiber or equal) [only covered when ultra-light materials are used in the fabrication of a socket for an endoskeletal prosthesis].
    L5950Addition, endoskeletal system, above knee, ultra-light material (titanium, carbon fiber or equal) [only covered when ultra-light materials are used in the fabrication of a socket for an endoskeletal prosthesis].
    L5960Addition, endoskeletal system, hip disarticulation, ultra-light material (titanium, carbon fiber or equal) [only covered when ultra-light materials are used in the fabrication of a socket for an endoskeletal prosthesis].
    L7510Repair prosthetic device, labor component, per 15 minutes.
    L7520Repair prosthetic device, labor component, per 15 minutes.
    L8400Prosthetic sheath, below knee.
    L8410Prosthetic sheath, above knee.
    L8417Prosthetic sheath/sock, including a gel cushion layer; below knee or above knee, each [12 in 12 months].
    1–10 of 15
    1/2
    Other CPT codes related to the CPBCPT
    27590 - 27596Amputation, thigh, through femur.
    HCPCS codes not covered for indications listed in the CPBHCPCSNot Covered
    K1007Bilateral hip, knee, ankle, foot device, powered, includes pelvic component, single or double upright(s), knee joints any type, with or without ankle joints any type, includes all components and accessories, motors, microprocessors, sensors.
    L5969Addition, endoskeletal ankle-foot or ankle system, power assist, includes any type motor(s).
    L5973Endoskeletal ankle foot system, microprocessor controlled feature, dorsiflexion and/or plantar flexion control, includes power source.
    L5990Addition to lower extremity prosthesis, user adjustable heel height.
    L7360Six volts battery, each.
    L7362Battery charger, six volts, each.
    L7364Twelve volts battery, each.
    L7366Battery charger, twelve volts, each.
    L7367Lithium ion battery, rechargeable, replacement.
    L7368Lithium ion battery charger, replacement only.
    1–10 of 11
    1/2
    ICD-10 codes covered if selection criteria are metICD-10Covered
    Q72.811 - Q72.899Other reduction defects of lower limb.
    S88.011+ - S88.929+Traumatic amputation of lower leg.
    S98.011+ - S98.929+Traumatic amputation of foot.
    Z89.411 - Z89.619Acquired absence of leg, toe(s), foot, and ankle.
    Z89.511 - Z89.529Acquired absence of leg below knee.
    Z89.611 - Z89.629Acquired absence of leg above knee.
    Protective outer covering systems - HCPCS codes covered if selection criteria are metHCPCSCovered
    L5704Custom shaped protective cover, below knee.
    L5705Custom shaped protective cover, above knee.
    L5706Custom shaped protective cover, knee disarticulation.
    L5707Custom shaped protective cover, hip disarticulation.
    L5962Addition, endoskeletal system, below knee, flexible protective outer surface covering system.
    L5964Addition, endoskeletal system, above knee, flexible protective outer surface covering system.
    L5966Addition, endoskeletal system, hip disarticulation, flexible protective outer surface covering system.
    Microprocessor-controlled leg prostheses - HCPCS codes covered if selection criteria are metHCPCSCovered
    L5615Addition, endoskeletal knee-shin system, 4 bar linkage or multiaxial, fluid swing and stance phase control.
    L5856Addition to lower extremity prosthesis, endoskeletal knee-shin system, microprocessor control feature, swing and stance phase; includes electronic sensor(s) any type [coverage limited per policy].
    L5857Addition to lower extremity prosthesis, endoskeletal knee-shin system, microprocessor control feature, swing phase only; includes electronic sensor(s), any type [coverage limited per policy].
    L5858Addition to lower extremity prosthesis, endoskeletal knee-shin system, microprocessor control feature, stance phase only; includes electronic sensor(s) any type [coverage limited per policy].
    L5926Addition to lower extremity prosthesis, endoskeletal, knee disarticulation, above knee, hip disarticulation, positional rotation unit, any type.
    L5973Endoskeletal ankle foot system, microprocessor controlled feature, dorsiflexion and/or plantar flexion control, includes power source.
    HCPCS codes not covered for indications listed in the CPB (additional)HCPCSNot Covered
    L5828Addition, endoskeletal knee-shin system, single axis, fluid swing and stance phase control.
    L5845Addition, endoskeletal, knee-shin system, stance flexion feature, adjustable.
    L5848Addition to endoskeletal knee-shin system, fluid stance extension, dampening feature, with or without adjustability.
    Accessory and repair codes considered medically necessaryHCPCSCovered
    L7510Repair prosthetic device, labor component, per 15 minutes.
    L7520Repair prosthetic device, labor component, per 15 minutes.

    Provider Requirements, Prior Authorization, and Documentation

    Prior Authorization

    Standard Written Order (SWO) required

    A completed Standard Written Order (SWO) must be sent to the supplier before submitting a claim; claims billed without an SWO will be denied as not medically necessary.

    Prior Authorization

    Prior authorization for listed HCPCS codes

    Prior authorization is required for covered HCPCS-listed prosthesis components and for microprocessor-controlled systems when the policy's selection criteria are met.

    Prior Authorization

    Prior authorization for powered prosthetic devices

    Prior authorization should document the clinical need for advanced powered devices (e.g., powered knees/feet) and account for device programming, batteries/charging, and user training requirements described by manufacturers and studies.

    Prior Authorization

    Prior authorization for powered exoskeletons

    Prior authorization for powered exoskeletons should specify the device type, intended setting (rehabilitation versus home), planned supervised training regimen, and risk mitigation given current evidence and device limitations.

    Prior Authorization

    Prior authorization likely required for exoskeletons

    Because evidence is limited and devices have substantial resource and safety implications, prior authorization may be required to support the use of powered exoskeletons and should include diagnosis, therapy goals, and a plan for supervised training.

    Prior Authorization

    Prior authorization for exoskeleton training programs

    Prior authorization for exoskeleton training should reflect typical training programs used in studies—generally three sessions per week for about eight weeks—and include objective gait outcome measures for monitoring.

    • Typical training dose: 3x/week for ~8 weeks
    • Include objective measures (10MWT, 6MWT, TUG) in authorization request
    Prior Authorization

    Prior authorization recommended for osseointegration

    Prior authorization is recommended for osseointegration to confirm the candidate meets selection criteria (for example, substantial socket intolerance) and that informed counseling on risks, benefits, and economic considerations has occurred.

    • Document prior socket intolerance and conservative management attempts
    • Document informed consent discussing infection and implant risks
    Billing Rule

    PDAC-verified HCPCS codes required

    Certain HCPCS codes (including some microprocessor-controlled lower limb product codes) may only be billed for products with PDAC coding verification; product details (manufacturer, part number/name) must be recorded in medical records.

    • Verify PDAC CVR for codes such as L5856/L5973 where applicable
    • Record manufacturer and part number in the medical record
    Note

    Verify plan-specific prior authorization requirements

    Check the member's plan provisions and the program provisions links to determine whether prior authorization is required for prosthetic devices for that specific plan.

    Note

    Prior authorization not specified in supplemental links

    The supplemental links and language services section lists resources and notices but does not state any prior authorization requirements.

    Note
    Note

    Therapeutic sequencing context — conventional prostheses as baseline

    The policy frames microprocessor-controlled devices and advanced technologies in the context of conventional mechanical prostheses and Medicare DME MAC criteria when considering therapeutic sequencing.

    Step Therapy

    Consider standard prosthesis trial before advanced feet

    Because evidence for microprocessor-controlled and powered feet is limited and mixed, consider a trial of standard ankle-foot prostheses before authorizing higher-technology powered or microprocessor-controlled options.

    Step Therapy

    Rehab-first approach for advanced devices

    Consider supervised rehabilitation-based use (structured training) before authorizing unsupervised or home use of advanced devices given evidence is largely from rehab settings and devices have functional limitations for community use.

    Step Therapy

    Consider conventional rehabilitation prior to exoskeletons

    Exoskeleton training is positioned as adjunctive to or instead of existing rehabilitation activities (physiotherapy, strength training, walking therapies); consider conventional rehabilitation before widespread exoskeleton use.

    Step Therapy

    Document conservative options before bionic/prosthetic upgrades

    Document prior attempts with conventional mechanical orthoses/feet and suspension optimization before requesting authorization for bionic or higher-technology prosthetic upgrades.

    Step Therapy

    Optimize socket and document failures before osseointegration

    Before considering osseointegration, document attempts to optimize socket fit and conservative management; osseointegration is emphasized as an option for selected patients who do not tolerate socket prostheses.

    Billing Rule

    Restriction: high-level (K3+) feet not allowed with preparatory prostheses

    K-3 and higher level feet are considered not medically necessary when provided with a preparatory prosthesis; verify that high-level feet are not billed with preparatory/initial prosthesis codes.

    Step Therapy

    Step therapy requirements not specified

    No step therapy requirements are specified in the policy excerpts provided.

    Note
    Documentation Required

    Functional level documentation required (K-level evidence)

    The prosthetist must document the expected functional ability in the patient's records; for K3 or higher, include a documented physical therapy evaluation to establish the functional level and activities—simply recording a K modifier is insufficient.

    • Retain detailed history and clinical findings supporting the K-level
    • Include PT evaluation documentation for K3+
    Billing Rule

    Include manufacturer/model when billing protective covers

    When billing protective outer surface covering systems (L5962, L5964, L5966), include the manufacturer name, make, model, or type in the practitioner's notes to ensure correct coding.

    Billing Rule

    Include appropriate HCPCS and ICD-10 codes on claims

    Claims must include the appropriate HCPCS codes for covered protective covers, additions, microprocessor-controlled knee and ankle-foot components, and the relevant ICD-10 diagnosis codes when selection criteria are met.

    Documentation Required

    Document programming, charging, and user training for powered devices

    Document device programming, battery charging procedures, and user training for powered knees and powered feet; initial practitioner programming and user charging/training are required for use.

    Documentation Required

    Document eligibility and program prerequisites

    For programs such as exoskeletons and osseointegration, document patient eligibility evidence (e.g., preserved upper-extremity function for crutch use, adequate bone mineral density, cardiovascular fitness) and include device model and training program details.

    • Record device model (e.g., ReWalk, Ekso) and planned training regimen
    • Document physical prerequisites (upper-extremity strength, bone density, CV fitness)
    Documentation Required

    Document training sessions and objective outcomes

    Maintain detailed training records: number and duration of sessions, assistance level, adverse events, and objective functional outcomes (walking time/distance) to demonstrate feasibility and clinical response.

    • Record assistance level and donning/doffing independence
    • Track walking speed and distance (10MWT, 6MWT)
    Documentation Required

    Retain clinical training logs with objective gait measures

    Maintain clinical training logs that document frequency of gait-training sessions, independence with donning/doffing, walking speed and distance (10MWT, 6MWT), and any adverse events to support medical necessity.

    Documentation Required

    Document candidate selection and informed consent for osseointegration

    For candidate selection and informed consent for procedures like osseointegration, document prior socket intolerance, attempts to optimize socket fit, and informed consent discussing infection risk, possible revision/extraction, and expected functional/QoL benefits.

    Documentation Required

    Functional ability documentation beyond K modifier

    Functional ability must be clearly documented in the prosthetist's records; recording only a K modifier is insufficient—supporting clinical evidence and PT evaluation for K3+ is required.

    Billing Rule

    PDAC CVR documentation required for specified HCPCS codes

    Products billed under specified HCPCS codes require a PDAC coding verification review (CVR) and Product Classification List entry; record product information such as manufacturer and part number in the medical record.

    Note

    Providers must verify plan-specific coverage and documentation

    Clinical Policy Bulletins are partial descriptions of plan benefits and do not constitute a contract; providers remain responsible for verifying coverage and specific plan documentation requirements.

    Note

    Supplemental resources and notices (no auth requirements stated)

    Supplemental resources (glossary, program provisions, legal notices, plan disclosures, language services) are provided for reference but do not state explicit authorization requirements.

    Denial Risk

    Claims risk: missing Standard Written Order (SWO)

    Claims submitted without a completed Standard Written Order (SWO) will be denied as not medically necessary.

    Denial Risk

    Claims risk: missing proof of delivery (POD)

    Services without appropriate proof of delivery (POD) documentation will be denied as not medically necessary; suppliers must maintain POD and provide it upon request.

    Denial Risk

    Denial risk for not-covered HCPCS codes

    Certain HCPCS codes are listed as not covered for indications in the clinical policy bulletin (for example, L5828, L5845, L5848); billing these codes for covered indications risks denial.

    • Examples listed: L5828, L5845, L5848
    Denial Risk

    Denial risk: insufficient evidence for powered/microprocessor feet

    Lack of sufficient clinical evidence and small sample sizes for powered feet and some microprocessor foot devices may lead payers to deny coverage in the absence of documented functional benefit.

    Denial Risk

    Denial risk from regulatory and risk uncertainty

    Diverse and evolving inclusion/exclusion criteria and incomplete understanding of device risks may result in rejected or deferred use until risk mitigation standards are defined.

    Denial Risk

    Evidence limitations may affect coverage decisions

    Evidence limitations (small, noncomparative studies and unclear resource impact) cited by reviews such as NICE may trigger coverage denial for domiciliary or broad clinical use without stronger evidence.

    Denial Risk

    Denial risk: insufficient safety monitoring/adverse event documentation

    Failure to document safety monitoring, device-related adverse events, or interruptions in training may risk denial or requests for additional information; studies report monitoring of skin issues and other AEs during training.

    Denial Risk

    Denial risk: infection/complication risk for osseointegration

    Significant infection and complication risks reported with osseointegration (superficial infection rates ~50% in some studies; deep/bone infections requiring long-term antibiotics or implant removal) may affect authorization decisions and require careful selection and documentation.

    Denial Risk

    Denial risk: not medically necessary additions with preparatory below-knee prostheses

    Additions and components listed in the appendix are considered not medically necessary when provided with initial or preparatory below‑knee prostheses; billing these additions with preparatory/initial prostheses risks denial.

    Denial Risk

    Denial risk: additions not covered with prefabricated preparatory prosthesis

    Additions and components listed are considered not medically necessary when provided with a below‑knee preparatory prefabricated prosthesis (L5535); billing these additions in that context risks denial.

    Denial Risk

    Denial risk: not medically necessary additions with preparatory/initial above-knee prostheses

    Additions and components listed are considered not medically necessary when provided with initial or preparatory above‑knee prostheses; billing these items with such prostheses risks denial.

    Denial Risk

    Administrative denial risk from incomplete documentation

    Administrative or missing documentation may affect coverage determinations; providers should ensure complete documentation and verify plan-specific requirements.

    Note

    Links-only section — no authorization requirements stated

    This section contains only links and notices and does not state authorization requirements; no provider action is specified here.

    Background and Evidence Summary

    K‑level classification (K0–K4) is used to assess rehabilitation potential and to guide selection of prosthetic components. The policy references K‑level categories to match device function to expected ambulatory ability and documents that prosthetist and, for K3 or higher, physical therapist evaluations are required to substantiate functional level and device appropriateness.

    Definitions and Key Terms

    inv-103: K-levels — Functional classification levels (K0–K4)
    K-levels definedFunctional classification levels K0 through K4 (Level 0 to Level 4)
    Level 0No potential to ambulate or transfer; prosthesis does not enhance mobility
    Level 4High-impact/athletic prosthetic demands; active adult or athlete
    inv-104: Proof of delivery (POD) — Supplier documentation that device was delivered; must be maintained and provided on request
    Proof of Delivery (POD)Supplier documentation that the device was delivered to the member; must be maintained and provided to Aetna upon request
    Denial riskServices without appropriate POD documentation will be denied as not medically necessary
    RecordkeepingSuppliers are required to maintain POD in their files and make it available on request
    inv-105: SACH foot — Definition and limitations
    DefinitionSACH foot: solid ankle cushion heel consisting of a rigid keel covered by semi-noncompressible foam and a synthetic rubber heel wedge
    Functional limitationSimulates plantar flexion but does not provide dorsiflexion, limiting usefulness on uneven surfaces
    Typical useAppropriate for lower functional levels (e.g., K1 household ambulator) rather than active community ambulation
    inv-106: Microprocessor-controlled prosthesis — Definition and examples (C-leg, Intelligent Prosthesis, Proprio-Foot)
    DefinitionMicroprocessor-controlled prosthesis: uses sensors and a microprocessor to adjust knee or ankle behavior in real time
    ExamplesC-Leg, Intelligent Prosthesis (IP), Proprio-Foot, Genium referenced in background evidence
    Claimed advantagesDecreased walking effort, improved gait symmetry, more natural movement on stairs/ramps, and reduced falls in selected users
    inv-107: Powered prosthetic knee — Definition (motorized knee with actuator)
    DefinitionPowered prosthetic knee: motorized knee with an electro-mechanical actuator that actively initiates and controls aspects of gait, providing powered flexion/extension under load
    ExamplePower Knee (Ossur) — motor provides active stance flexion/extension and requires practitioner programming and battery charging
    RequirementsRequires batteries/charging and initial practitioner programming/alignment
    inv-108: Powered prosthetic foot — Definition (powered plantar flexion to replicate calf function)
    DefinitionPowered prosthetic foot: a below-knee robotic prosthesis that provides powered plantar flexion (push-off) to replicate calf muscle function
    ExampleBiOM/PowerFoot — provides powered push-off to normalize gait and reduce metabolic cost
    User needsRequires charging and may improve ankle power and decrease oxygen consumption in preliminary studies
    inv-109: Wearable robotic exoskeleton — Definition (motorized brace with powered hip/knee joints and backpack controller)
    DefinitionWearable robotic exoskeleton: motorized brace system with powered hip and knee joints, backpack controller/batteries, requiring crutches and trained supervision
    Intended usersOften indicated for people with paraplegia (SCI) who can use crutches and have adequate bone density and cardiovascular fitness
    ExamplesReWalk, Ekso GT, Indego referenced as wearable exoskeleton systems
    inv-110: Powered exoskeleton (ReWalk/Ekso) — Definition and basic device description
    DefinitionPowered exoskeleton (ReWalk/Ekso): a wearable, computer-controlled motorized orthosis with sensors, batteries and onboard computer (often in a backpack) enabling ambulation with crutches
    ReWalk descriptionReWalk personal system: computer-controlled motorized leg braces with backpack computer and batteries used with crutches
    Ekso descriptionEkso (Ekso GT) is a 45 lb system with SmartAssist software and ~3 hour battery life per manufacturer
    inv-111: Level of assistance (LOA) — Definitions for assistance categories during exoskeleton walking
    DefinitionLevel of assistance (LOA): categories describing required assistance during exoskeleton-assisted walking (modified independence, supervision, minimal assistance, moderate assistance)
    Use in studiesLOA used to correlate gait speed and independence in clinical evaluations (e.g., ReWalk studies)
    Outcome relevanceLOA informs safety and training needs in supervised rehabilitation programs
    inv-112: Ekso (EKSO GT) — Device description and weight
    DeviceEkso (EKSO GT) — a motorized exoskeleton for rehabilitation with SmartAssist software
    WeightApproximately 45 lb system (manufacturer-stated)
    Battery lifeManufacturer estimates ~3 hours of battery life
    inv-113: HAL (Hybrid Assistive Limb) — Definition and use
    DefinitionHAL (Hybrid Assistive Limb): robotic exoskeleton that monitors muscle contractions via surface EMG to provide voluntary machine-supported motion
    UseUsed for intensive gait training after stroke and spinal cord injury to induce cortical plasticity and improve walking parameters
    Training duration reportedExample study: HAL-assisted BWSTT for 3 months in 11 SCI patients with walking parameter improvements
    inv-114: Indego — Definition (Indego exoskeleton)
    DefinitionIndego: powered exoskeleton with 4 motors for bilateral hip and knee movement and built-in AFOs
    Learning/usabilityPilot studies report ease of learning, donning/doffing progression, and post-training walking speeds varying by injury level
    Training protocolReported protocols include 5-session pilots and multicenter 8-week (3x/week) programs showing improved speeds and endurance
    inv-115: Proprio-Foot — Definition (Proprio-Foot microprocessor-controlled adaptive ankle)
    DefinitionProprio-Foot: microprocessor-controlled adaptive ankle that provides swing-phase dorsiflexion and adaptive response to terrain
    FunctionAdjusts dorsiflexion during swing to improve stair negotiation and inter-limb symmetry
    ConsiderationsAdds weight but may benefit active transtibial amputees with sufficient knee musculature
    inv-116: Osseointegration (OI) — Definition of two-stage surgical implant procedure
    DefinitionOsseointegration (OI): two-stage surgical procedure implanting a titanium fixture into bone with later skin-penetrating abutment to attach external prosthesis
    Clinical implicationsCan improve function but associated with substantial risks including infection and fractures; requires careful candidate selection
    Evidence summarySystematic reviews report improved clinical outcomes but overall infection rates around 32% and variable follow-up
    inv-117: MPC/Active hydraulic ankle-foot — Definition and examples
    DefinitionMPC/Active hydraulic ankle-foot: ankle-foot devices using sensors and microprocessor logic to adapt resistance/motion (e.g., ramp-descent mode)
    ExamplesMicroprocessor-controlled hydraulic ankles and adaptive devices (Pro-Flex, Proprio) described in studies
    Clinical effectMay reduce compensatory knee work and improve descent mechanics in small studies
    inv-118: ESAR / Pro-Flex / Novel Foot definitions — Energy storing and returning foot types
    DefinitionESAR / Pro-Flex / Novel Foot (NF): energy storing and returning feet designed to store energy during stance and release during propulsion
    Potential benefitsMay increase range of motion, ankle power, and reduce loading on the sound limb in small studies
    Study sizesEvidence primarily from small cohorts (often n ≤ 11) with limited generalizability
    inv-119: Rehabilitation potential levels (K-level analog) — Level 0–4 descriptions
    DefinitionRehabilitation potential levels (K-level analog) Level 0–4 describing expected ambulation/transfer potential
    Level descriptionsLevel 0: no potential; Level 1: transfers/ambulation on level surfaces; Level 2: ambulation with low-level barriers; Level 3: variable cadence community ambulator; Level 4: high-impact/athletic demands
    DocumentationFunctional ability must be documented by prosthetist and PT; K-modifier alone insufficient
    inv-120: Clinical Policy Bulletin — Definition and disclaimer
    DefinitionClinical Policy Bulletin: Aetna document to assist administering plan benefits; does not constitute an offer of coverage or medical advice
    UsageProvides policy guidance, coding, evidence summaries, and documentation/prior authorization notes
    Denial risk noteCoverage determinations remain subject to individual plan provisions and documentation requirements