Valid from 16 September 2024

Click here to download the current ODEP Ankles (PDF)

ODEP welcomes submissions for Total Ankle Replacements and Total Talus Replacements. The ODEP rating applies to the complete construct, rather than to individual components. A construct represents a unique combination of components (or catalogue numbers) that together form the implanted device.

What constitutes a construct?
A Total Ankle Replacement construct is defined by the specific combination of tibial component, talar component, and bearing insert (where applicable). Each unique combination of these elements is treated as a separate construct for the purposes of ODEP rating.

What must be identical across a construct?
For components to be grouped within a single construct, the following characteristics must be identical:

Tibial Component

• Material composition (e.g. titanium alloy, cobalt chrome)
• Surface finish and coating (e.g. hydroxyapatite, titanium plasma spray, porous tantalum, uncoated)
• Fixation features (e.g. keel, pegs, stem, press-fit fins, intramedullary stem)
• Method of fixation (cemented vs. uncemented)

Talar Component

• Material composition (e.g. cobalt chrome, titanium alloy, titanium nitride-coated)
• Surface finish and coating
• Talar geometry and resection type (i.e. flat cut, chamfered cut — see below)
• Fixation features (e.g. pegs, keel, fins, sulcus geometry)
• Method of fixation (cemented vs. uncemented)

Bearing / Polyethylene Insert

• Bearing type: mobile bearing vs. fixed bearing (these are always separate constructs)
• Material (e.g. conventional UHMWPE, highly cross-linked polyethylene, vitamin E-stabilised XLPE)
• Conformity and articular geometry

Flat cut vs. chamfered talar constructs
Implant systems that offer both flat cut and chamfered talar resection geometries shall be treated as separate constructs, as these represent fundamentally different bone–implant interfaces with distinct biomechanical characteristics and potentially different clinical outcomes. Constructs must therefore be submitted and rated independently for each talar resection geometry.

Mobile bearing vs. fixed bearing constructs
Three-component mobile bearing designs (in which the polyethylene insert articulates independently with both the tibial and talar metallic components) and two-component fixed bearing designs (in which the polyethylene is locked to the tibial baseplate) represent fundamentally different design philosophies. These are always treated as separate constructs and must be submitted independently.

Surgical approach
Where an implant system is designed for use exclusively via a specific surgical approach (e.g. anterior approach vs. lateral transfibular approach), and where the approach mandates a different implant geometry, component design, or instrumentation that results in different catalogue numbers, these shall be treated as separate constructs.

Where the same implant components (identical catalogue numbers) may be inserted via different surgical approaches at the surgeon’s discretion, these are not considered separate constructs.

Size variations
Different sizes within the same component design family do not constitute separate constructs, provided all other characteristics listed above remain identical. However, where a manufacturer markets a distinct sub-range (e.g. a “narrow” or “wide” tibial tray with a different geometry or surface profile, not simply a scaled version of the standard component), this shall be treated as a separate construct.

Total Talus Replacements are assessed as a distinct implant category. A Total Talus Replacement construct is defined by the specific prosthesis that replaces the entire body of the talus (typically a custom or semi-custom metallic implant), together with any associated tibial resurfacing or bearing component where applicable.

For Total Talus Replacements, the following characteristics must be identical across a construct:

• Material composition (e.g. cobalt chrome, titanium alloy, 3D-printed titanium)
• Manufacturing method (e.g. standard off-the-shelf, patient-specific/custom-manufactured)
• Articular surface finish and geometry
• Associated tibial component and/or bearing (if part of the system)
• Associated fixation methods to the calcaneum and naviculr

Patient-matched Total Talus Replacements may be eligible for a Patient Matched ODEP rating, subject to the same criteria applied to Patient Matched implants in other joints.

The benchmark criteria for Total Ankle Replacements and Total Talus Replacements follow the standard ODEP rating framework. The ODEP rating for an ankle construct is determined by the rating achievable by the most recently introduced component within that construct.

Minimum volume requirements
Given the relatively low volume of ankle arthroplasty procedures performed annually, the Panel has set minimum cohort sizes that reflect realistic clinical practice whilst maintaining statistical robustness. These minimum volumes apply at each benchmark time point and are specified in the submission documentation.

Construct-level rating
The ODEP rating for a Total Ankle Replacement or Total Talus Replacement is awarded at the construct level. Where a construct comprises components of differing individual maturity, the overall rating is determined by the most recently introduced component. For example, if a tibial component has sufficient data to support a 10A rating but the talar component has only been in use long enough to support a 5A rating, the Manufacturer can apply for the 5-year rating.

Component changes within a product family
Any change to a component that results in a new catalogue number is treated as a new component for the purposes of ODEP rating. This includes, but is not limited to, changes in:

• Material composition or alloy specification
• Surface finish, coating, or ingrowth surface
• Fixation geometry (e.g. addition or removal of pegs, keels, or stems)
• Articular geometry or bearing conformity
• Polyethylene type or sterilisation method
• Bone resection geometry (e.g. flat cut to chamfered cut)

The manufacturer must clearly identify which catalogue numbers are included within each submitted construct.

Polyethylene insert exchanges
Where a bearing or polyethylene insert is exchanged in isolation (i.e. without revision of the metallic components), the Panel will consider whether this constitutes a revision for the purposes of ODEP assessment, consistent with the definitions used by the relevant national joint registries. However, a change in articular geometry would be considered reason for ODEP re-assessment.

Review
The Panel recognises that the field of total ankle arthroplasty continues to evolve and that the assessment criteria will be regularly reviewed to ensure that the ratings awarded remain robust and reflective of the current evidence base. The methodology described above will be reviewed periodically in line with standard ODEP practice.

As has been noted in other sections of the website, ODEP expects that data sources used by manufacturers for their submissions should come from validated sources. Registry data will always be accepted from registries which comply with the ISAR standards for a level 1 registry where compliance and completeness are over 90%. Peer reviewed publications and presentations are accepted provided they cover the areas of inquiry stipulated in the submission form.

ODEP encourages manufacturers to monitor their products carefully and in-house data that is validated (or can be validated by ODEP) is accepted in certain circumstances. The data collection must fit the submission form perfectly. If in house data is submitted from hospitals in an area of the world where there is a registry, data from that registry (however limited) must be included.
Registry data must be contemporary. If a manufacturer is using NJR data it should be no longer than 6 months old. Data extracted from other registries should be no older than the date of the registry’s annual report. ODEP keeps a record of the dates at which registries publish their annual reports.

After due diligence, ODEP will publish, on their website, the names of implants marked unacceptable and also those with lapsed ratings. ODEP will publish, alongside the details of these implants, any explanatory comments by the manufacturer if they are submitted in a timely manner.