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AvalonK2 Hydraulic K2 Prosthetic Ankle

AvalonK2 is a hydraulic ankle that has been designed specifically for the complex needs of limited community ambulators. Through a combination of award-winning hydraulic ankle technology and a unique optimised keel, Blatchford has created a prosthesis that works with the user to enhance confidence, independence and safety.

Enhancing walking confidence by hydraulically adjusting to inclines and self-aligning to secure the knee joint, AvalonK2 encourages good posture and joint position. This improves stability, helping to prevent falls and increases balanced limb loading to provide the best performance for limited community ambulators.

  • Activity level 2
  • Submersion to a depth of 1m

AvalonK2 Unique Design

The Avalon range enhances walking confidence by hydraulically adjusting to inclines and self-aligning to secure the knee joint, to encourage good posture and joint position. This improves stability, helping to prevent falls and increases balanced limb loading to provide the best performance for limited community ambulators.

The main driving force behind advancing lower limb prosthetic technology in the 21st century is biomimetic design; reproducing the biomechanical performance of natural limbs. Inherent in this is recognising that different demographics of the amputee population have different biomechanical requirements, and that the engineering principles behind different devices must accommodate for this.

With over 130 years of innovation and expertise in lower limb prosthetic technology our award-winning prosthetic products are designed with the patient in mind.

Explore Features

Hydraulic Ankle Technology

Hydraulic ankles help align the body interface with the ground interface, allowing for more natural movement and posture. By continuously adjusting to absorb energy, our hydraulic ankles allow for an efficient roll-over, remaining in a dorsiflexed position, increasing clearance to help reduce the risk of falls. This technology has been proven to provide a number of benefits to limited community ambulators optimising posture and comfort.

This K2 foot allows patients K2 level patients to walk with a smoother rollover. 

  • Purpose Designed Keel

    Purpose Designed Keel

    Limited community ambulators tend to walk more slowly, with a shorter step and stride length. Providing a foot keel that is designed to accommodate natural changes in gait can provide a smoother rollover for such users. The optimised keel shape of the Avalon range considers such requirements and encourages a consistent, stable, and comfortable rollover so the user can walk more easily and move around confidently.

  • Range of Motion

    Range of Motion

    AvalonK2 offers a range of motion of 6˚ plantar and 6˚ dorsiflexion with a single hydraulic adjustment function. This range of motion improves ground clearance when walking but also increases stability when sitting down or standing up, a particular benefit for the low activity K2 users.

Scientifically Proven

Avalon White Paper Cover E1571644271787

White Paper: A Study of AvalonK2

To take a more in-depth look into AvalonK2, discover our White Paper ‘A Study of AvalonK2’ where the biomechanics of the limited community ambulators gait are considered along with the latest clinical evidence for biomimetic hydraulic technology. Then uncover how the biomechanical performance of AvalonK2 can improve mobility and independence.


White Paper: A Study of Residual Limb Health

While prosthetic technology edges ever closer to restoring natural performance, there is also a more basic consideration – the residuum-socket interface. Even with the world’s most advanced prosthetic limb, if it is not comfortable to wear and walk with, amputees will not use it. Socket fit and comfort are inextricably linked to residual limb health, making this a critical element in achieving and maintaining a successful prosthetic prescription.

Hydraulic Ankle White Paper Cover

White Paper: A Study of Hydraulic Ankles

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’. 

Clinical Compendium Cover 1

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

AvalonK2 Clinical Evidence Reference

Improvements in Clinical Outcomes using Avalon compared to non-hydraulic feet

  • Mobility

    Improved gait performance

    • Faster self-selected walking speed1
    • Smoother centre-of-pressure progression1

    Keel and ankle designed for Activities of Daily Living

    • Easier sit-to-stand2
  • Loading symmetry
    • Mean 34% reduction in stance phase timing asymmetry3
    • Maximum 86% reduction in stance phase timing asymmetry3
    • More symmetrical inter-limb loading1
  • User satisfaction

    Patient reported outcome measures indicate improvements

    • Mean improvement across all Prosthesis Evaluation Questionnaire domains4

Clinical Outcomes using the Avalon/Navigator keel design

  • Mobility
    • Shorter keel allows for more consistent rollover radius of curvature, regardless of changing footwear5
    • The most energy efficient radius of curvature for a rollover shape has been identified as 30% of the walker’s leg length. For a person of a typical adult height between 1.5m and 1.8m, this equates to approximately 245-290mm. The Avalon keel design has a rollover shape of ~250mm5


  • Full Reference Listing
    1. Barnett CT, Brown OH, Bisele M, et al.

      Individuals with Unilateral Transtibial Amputation and Lower Activity Levels Walk More Quickly when Using a Hydraulically Articulating Versus Rigidly Attached Prosthetic Ankle-Foot Device. JPO J Prosthet Orthot 2018; 30: 158–64.

    2. McGrath M, Moser D, Baier A.

      Anforderungen an eine geeignete Prosthesentechnologie für ältere, dysvaskuläre Amputierte - Requirements of a suitable prosthesis technology for elderly, dysvascular amputees. Orthop-Tech; 11.

    3. Moore R.

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

    4. Moore R.

      Patient Evaluation of a Novel Prosthetic Foot with Hydraulic Ankle Aimed at Persons with Amputation with Lower Activity Levels. JPO J Prosthet Orthot 2017; 29: 44–47.

    5. Curtze C, Hof AL, van Keeken HG, et al.

      Comparative roll-over analysis of prosthetic feet. J Biomech 2009; 42: 1746–1753.

AvalonK2 Documentation

**Component weight shown is without foot shell.