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Elan

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Experience smoother, safer and more natural walking

Elan is a microprocessor controlled foot that mimics natural muscle resistance and ankle motion by adapting hydraulic resistance levels to optimise stability when standing and walking, on slopes and uneven terrain. This encourages more symmetrical limb loading, faster walking speed and reduced compensatory movements. The ankle pivot point is optimally positioned close to the natural weight line for a more natural response through the gait cycle. The result is smoother, safer and more natural walking, helping to preserve the body for the long term.

 

  • Standing Support Mode

    Standing Support Mode

    When no movement is sensed, the hydraulics stiffen to assist with a natural standing posture, providing equal socket pressures.

  • Integrated Micro Connector

    Integrated Micro Connector

    The refreshed design incorporates an integrated charging connector with a new LED battery power indicator.

  • Simplified Clinician Setup

    Simplified Clinician Setup

    The new software interface has been simplified and refined so that it is now easier than ever for clinicians to set up Elan.

  • Even Longer Battery Life

    Even Longer Battery Life

    The battery life is now even longer with up to two days usage between charges and a low power mode.

Ramp Brake

On walking downhill, lower plantarflexion resistance allows the foot to fully contact the slope sooner for improved safety and security. At the same time, increased dorsflexion resistance provides a braking effect stabilising the user for a safer, more controlled descent

Ramp Assist / Fast Walk

When walking quickly or up slopes, the plantarflexion resistance increases allowing for more optimal energy storage and return. Combined with a softer dorsflexion resistance, this aids forward momentum, body position and minimises the effort required to walk fast or uphill.

Standing Support

Standing for longer periods has also just got easier. A network of sensors detect the user is stationary, increasing resistance to help improve balance, stability reduce effort and encourage a more natural posture.

Standing Support

During swing phase, the ankle remains in a dorsiflexed position increasing toe clearance on every step and reducing the risk of stumbles or falls

Scientifically Proven

Hydraulic Ankle White Paper Cover

Hydraulic Ankles White Paper

Over a decade after challenging conventional wisdom, new scientific evidence continues to be published on the medical advantages of hydraulic ankles. Discover our White Paper ‘A Study of Hydraulic Ankles’.

Hydraulic ankles, provide an alternative to this conventional design, creating a more biomimetic model. This design still incorporates ‘heel’ and ‘toe’ springs, but rather than a rigid ‘ankle’, there is a joint.

Hydraulic damping is used to influence the movement of this joint, producing a viscoelastic property closer to the behaviour of human muscle.

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Clinical Compendium Cover 1

Hydraulic Ankles - Clinical Compendium

Blatchford Biomimetic Hydraulic Technology mimics the dynamic and adaptive qualities of muscle actuation to encourage more natural gait. Multiple independent scientific studies, comparing Blatchford hydraulic ankle-feet to non-hydraulic feet, have shown:

  • Greater comfort, reduced socket pressures
  • Improved safety, reduced risk of trips and falls
  • Smoother, easier and more natural gait
  • More evenly balanced inter-limb loading
  • Greater satisfaction
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Elan Clinical Evidence Reference

Improvements in Clinical Outcomes using Elan compared to ESR feet

  • Safety

    Reduced risk of tripping and falls

    • Increased minimum toe clearance during swing phase1,2

    Improved knee stability on the prosthetic side during slope descent

    • Increased mid-stance external prosthetic knee extensor moment3

    Improving standing balance on a slope

    • 24-25% reduction in mean inter-limb centre-of-pressure root mean square (COP RMS)4
  • Energy Expenditure

    Reduced energy expenditure during walking

    • Mean 11.8% reduction in energy use on level ground, across all walking speeds5
    • Mean 20.2% reduction in energy use on slopes, across all gradients5
    • Mean 8.3% faster walking speed for the same amount of effort5
  • Mobility

    Improved gait performance

    • Faster self-selected walking speed2,6-9

    Improved ground compliance when walking on slopes

    • Increased plantarflexion peak during level walking, fast level walking and cambered walking10
    • Increased dorsiflexion peak during level walking, fast level walking and cambered walking10

    Less of a prosthetic “dead spot” during gait

    • Reduced aggregate negative COP displacement7
    • Centre-of-pressure passes anterior to the shank statistically significantly earlier in stance7
    • Increased minimum instantaneous COM velocity during prosthetic-limb single support phase7
    • Reduced peak negative COP velocity9
    • Reduced COP posterior travel distance9

    Improved ground compliance when walking on slopes

    • Increased plantarflexion range during slope descent3
    • Increased dorsiflexion range during slope ascent3

    Less effort on residual hip for trans-femoral amputees on varied terrains

    • Reduced the mean hip extension and flexion moments11

    Effects consistent over time

    • Same gait variable changes in two gait lab sessions one year apart6
    • Magnitude of changes comparable between sessions6

    Brake mode during slope descent to control momentum build up

    • Reduced mean prosthetic shank angular velocity in single support12
    • Increased Unified Deformable Segment (prosthetic ‘ankle’) negative work12

    Less gait compensation movements during slope descent

    • Reduced residual knee flexion at loading response12
  • Residual Limb Health

    Helps protect vulnerable limb tissue, reducing likelihood of damage

    • Reduced peak stresses on residual limb13
    • Reduced stress RMS on residual limb13
    • Reduced loading rates on residual limb13
  • Loading symmetry

    Greater contribution of prosthetic limb to support during walking

    • Increased residual knee peak extension moment6
    • Decreased residual knee peak flexion moment6
    • Increased residual knee negative work8

    Reduced reliance on sound limb for support during walking

    • Reduced intact limb peak hip flexion moment8
    • Reduced intact limb peak dorsiflexion moment8
    • Reduced intact ankle negative work and total work8
    • Reduced intact limb total joint work8

    Better symmetry of loading between prosthetic and sound limbs during standing on a slope

    • Degree of asymmetry closer to zero for 5/5 amputees4

    Reduced residual and sound joint moments during standing of a slope

    • Significant reductions in both prosthetic and sound support moments14

    Reduced residual joint moments during standing of a slope for bilateral amputees

    • Significant reductions in prosthetic support moment14
    • Permitted ‘natural’ ground reaction vector sagittal plane position, relative to knee joint centres14

    Less pressure on the sole of the contralateral foot

    • Peak plantar-pressure15

    Improved gait symmetry

    • Reduced stance phase timing asymmetry16
  • User satisfaction

    Patient reported outcome measures indicate improvements

    • Mean improvement across all Prosthesis Evaluation Questionnaire domains17
    • Bilateral patients showed highest mean improvement in satisfaction17

    Subjective user preference for hydraulic ankle

    • 13/13 participants preferred hydraulic ankle15

Improvements in Clinical Outcomes using Elan compared to non-microprocessor-control hydraulic ankle-feet

  • Safety

    Improved knee stability on the prosthetic side during slope descent

    • Increased mid-stance external prosthetic knee extensor moment3
  • Mobility

    Improved ground compliance when walking down slopes

    • Reduced time to foot flat12

    Brake mode during slope descent increases resistance to dorsiflexion to control momentum build up

    • Reduced dorsiflexion range during slope descent3
    • Reduced mean prosthetic shank angular velocity in single support12
    • Increased Unified Deformable Segment (prosthetic ‘ankle’) negative work12
    • Transition from dorsiflexion to plantarflexion moment occurs earlier in stance phase18
    • Increase in mean prosthetic ‘ankle’ plantarflexion moment integral18

    Assist mode during slope ascent decreases resistance to dorsiflexion to allow easier progression

    • Transition from dorsiflexion to plantarflexion moment occurs later in stance phase18
    • Decrease in mean prosthetic ‘ankle’ plantarflexion moment integral18

    Less gait compensation movements during slope descent

    • Reduced residual knee flexion at loading response12
  • Loading symmetry

    Greater reliance on prosthetic side for bodyweight support during slope descent

    • Increased support moment integral18

    Less reliance on sound side for bodyweight support during slope descent

    • Decreased support moment integral18

    Less reliance on sound side for bodyweight support during slope ascent

    • Decreased support moment integral18

    Reduced sound joint moments during standing of a slope

    • Significant reductions in sound support moment14

    Reduced residual joint moments during standing of a slope for bilateral amputees

    • Significant reductions in prosthetic support moment14
    • Permitted ‘natural’ ground reaction vector sagittal plane position, relative to knee joint centres14

References

  • Full Reference Listing

    1. Riveras M, Ravera E, Ewins D, Shaheen AF, Catalfamo-Formento P.

      Minimum toe clearance and tripping probability in people with unilateral transtibial amputation walking on ramps with different prosthetic designs. Gait & Posture. 2020 Sep 1;81:41-8.

    2. Johnson L, De Asha AR, Munjal R, et al.

      Toe clearance when walking in people with unilateral transtibial amputation: effects of passive hydraulic ankle. J Rehabil Res Dev 2014; 51: 429.

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    3. Bai X, Ewins D, Crocombe AD, et al.

      A biomechanical assessment of hydraulic ankle-foot devices with and without micro-processor control during slope ambulation in trans-femoral amputees. PLOS ONE 2018; 13: e0205093.

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    4. McGrath M, Laszczak P, Zahedi S, et al.

      Microprocessor knees with “standing support” and articulating, hydraulic ankles improve balance control and inter-limb loading during quiet standing. J Rehabil Assist Technol Eng 2018; 5: 2055668318795396.

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    5. Askew GN, McFarlane LA, Minetti AE, et al.

      Energy cost of ambulation in trans-tibial amputees using a dynamic-response foot with hydraulic versus rigid ‘ankle’: insights from body centre of mass dynamics. J NeuroEngineering Rehabil 2019; 16: 39.

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    6. De Asha AR, Barnett CT, Struchkov V, et al.

      Which Prosthetic Foot to Prescribe?: Biomechanical Differences Found during a Single-Session Comparison of Different Foot Types Hold True 1 Year Later. JPO J Prosthet Orthot 2017; 29: 39–43.

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    7. De Asha AR, Munjal R, Kulkarni J, et al.

      Impact on the biomechanics of overground gait of using an ‘Echelon’hydraulic ankle–foot device in unilateral trans-tibial and trans-femoral amputees. Clin Biomech 2014; 29: 728–734.

    8. De Asha AR, Munjal R, Kulkarni J, et al.

      Walking speed related joint kinetic alterations in trans-tibial amputees: impact of hydraulic’ankle’damping. J Neuroengineering Rehabil 2013; 10: 1.

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    9. De Asha AR, Johnson L, Munjal R, et al.

      Attenuation of centre-of-pressure trajectory fluctuations under the prosthetic foot when using an articulating hydraulic ankle attachment compared to fixed attachment. Clin Biomech 2013; 28: 218–224.

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    10. Bai X, Ewins D, Crocombe AD, et al.

      Kinematic and biomimetic assessment of a hydraulic ankle/foot in level ground and camber walking. PLOS ONE 2017; 12: e0180836.

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    11. Alexander N, Strutzenberger G, Kroell J, et al.

      Joint Moments During Downhill and Uphill Walking of a Person with Transfemoral Amputation with a Hydraulic Articulating and a Rigid Prosthetic Ankle—A Case Study. JPO J Prosthet Orthot 2018; 30: 46–54.

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    12. Struchkov V, Buckley JG.

      Biomechanics of ramp descent in unilateral trans-tibial amputees: Comparison of a microprocessor controlled foot with conventional ankle–foot mechanisms. Clin Biomech 2016; 32: 164–170.

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    13. Portnoy S, Kristal A, Gefen A, et al.

      Outdoor dynamic subject-specific evaluation of internal stresses in the residual limb: hydraulic energy-stored prosthetic foot compared to conventional energy-stored prosthetic feet. Gait Posture 2012; 35: 121–125.

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    14. McGrath M, Davies KC, Laszczak P, et al.

      The influence of hydraulic ankles and microprocessor-control on the biomechanics of trans-tibial amputees during quiet standing on a 5° slope. Can Prosthet Orthot J; 2.

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    15. Moore R.

      Effect of a Prosthetic Foot with a Hydraulic Ankle Unit on the Contralateral Foot Peak Plantar Pressures in Individuals with Unilateral Amputation. JPO J Prosthet Orthot 2018; 30: 165–70.

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    16. Moore R.

      Effect on Stance Phase Timing Asymmetry in Individuals with Amputation Using Hydraulic Ankle Units. JPO J Prosthet Orthot 2016; 28: 44–48.

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    17. Sedki I, Moore R.

      Patient evaluation of the Echelon foot using the Seattle Prosthesis Evaluation Questionnaire. Prosthet Orthot Int 2013; 37: 250–254.

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    18. McGrath M, Laszczak P, Zahedi S, et al.

      The influence of a microprocessor-controlled hydraulic ankle on the kinetic symmetry of trans-tibial amputees during ramp walking: a case series. J Rehabil Assist Technol Eng 2018; 5: 2055668318790650.

      Download

Elan Documentation