Elan
3 Elan is a microprocessor 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.
Key Features
- Microprocessor controlled self-aligning plantarflexion and dorsiflexion
- Standing support mode increases resistance when stationary to help improve balance, stability, reduce effort and encourage a more natural posture
- Variable response to speed changes
- Increased plantarflexion resistance allows for more energy storage and return when walking quickly or up slopes
- Ankle remains dorsiflexed during swing phase to increase toe clearance and reduce risk of trips and falls
- Batteries contained within the ankle
- Increased dorsiflexion resistance provides a brake when walking down slopes for improved safety and stability
- Sandal Toe Foot Shell
Key Benefits
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
The refreshed design incorporates an integrated charging connector with a new LED battery power indicator.
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
The battery life is now even longer with up to two days usage between charges and a low power mode.
Why Elan is Different
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 dorsiflexion 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 dorsiflexion 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.
Swing Clearance
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
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
Clinical Evidence
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’.
Elan Clinical Evidence Reference
Improvements in Clinical Outcomes using Elan compared to ESR feet
- 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
- 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
- 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
- Helps protect vulnerable residual limb tissue, reducing likelihood of damage
- Reduced peak stresses on residual limb13
- Reduced stress RMS on residual limb13
- Reduced loading rates on residual limb13
- 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
- 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
- Improved knee stability on the prosthetic side during slope descent
- Increased mid-stance external prosthetic knee extensor moment3
- 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
- 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
| 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 Overview |
See all the Clinical Evidence for every Blatchford product in our Clinical Evidence Finder Tool.
Elan Technical Data
Max. User Weight:
125kg*
275lb*
Activity Level:
3
Size Range:
22-30cm
Component Weight:
920g†
2lb†
Build Height:
170-175mm
6¹¹/₁₆" - 6⁵⁷/₆₄"
Heel Height:
10mm
*For weights above 125kg up to 150kg contact a Blatchford representative.
†Component weight shown is for a size 26cm without foot shell.
Selection Guide
Click the image for full size version.
Foot Shell Width Guide
Click on the table below to help choose the correct width when ordering the new Sandal Toe Foot Shell. For sizes 25, 26 and 27 you can now choose between Narrow (N) and Wide (W) fittings.
Accessories
| Alignment Wedge | 940093 |
| Spare Battery Charger Kit | 409087E |
| Programming Tablet | 019179 |
Ordering
Example Order Number
| ELAN | 25 | L | N | 3 | S |
| Product Code | Size | Side | Width* | Spring Set | Sandal Toe |
*Narrow (N) and Wide (W) available for sizes 25-27 only.
For dark tone add suffix D.
Example: foot size 25, left, narrow, spring rating 3, sandal toe.
Elan Documentation
Product Information
Technical Guides
Science & Education
Other downloads
- Elan - Elan Charger Adapter Kit
- Elan - Sandal Toe Foot Range Information
- Elan - Hydraulic Ankle Technology Brochure