The Kinos Axiom Total Ankle System is indicated for patients with ankle joints damaged by severe rheumatoid, posttraumatic, or degenerative arthritis. The Kinos Total Ankle System is additionally indicated for patients with failed previous ankle surgery. The Kinos Axiom Total Ankle System is intended for cement use only.
Device Story
Fixed-bearing, semi-constrained total ankle replacement system; replaces articulating surfaces of tibial-talar joint. System comprises tibial implant, bearing implant, and talar implant. Tibial implant features modified stem for tibial fixation; additively manufactured from Ti-6Al-4V. Used by orthopedic surgeons in clinical settings to restore joint alignment, reduce pain, and provide flexion-extension movement. Implanted via surgical procedure using bone cement. Benefits include motion preservation and pain relief for patients with severe arthritis or failed prior surgery.
Clinical Evidence
Bench testing only. Performance testing included strength testing per ASTM F2665, bone stability testing, porous surface characterization, and biocompatibility testing per ISO 10993-1:2018.
Technological Characteristics
Fixed-bearing, semi-constrained ankle prosthesis. Tibial implant additively manufactured from Ti-6Al-4V (ASTM F2924). Intended for cemented fixation. System includes tibial, bearing, and talar components.
Indications for Use
Indicated for patients with ankle joints damaged by severe rheumatoid, post-traumatic, or degenerative arthritis, or failed previous ankle surgery. Intended for cement use only.
Regulatory Classification
Identification
An ankle joint metal/polymer semi-constrained cemented prosthesis is a device intended to be implanted to replace an ankle joint. The device limits translation and rotation in one or more planes via the geometry of its articulating surfaces and has no linkage across-the-joint. This generic type of device includes prostheses that have a talar resurfacing component made of alloys, such as cobalt-chromium-molybdenum, and a tibial resurfacing component made of ultra-high molecular weight polyethylene and is limited to those prostheses intended for use with bone cement (§ 888.3027).
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Image /page/0/Picture/0 description: The image shows the logo of the U.S. Food and Drug Administration (FDA). The logo consists of two parts: the Department of Health and Human Services logo on the left and the FDA logo on the right. The FDA logo features the letters "FDA" in a blue square, followed by the words "U.S. FOOD & DRUG ADMINISTRATION" in blue text.
November 28, 2023
restor3d Brianna Prindle Head of Regulatory 4001 E. NC 54 Highway Suite 3160 Durham, North Carolina 27709
Re: K232595
Trade/Device Name: Kinos Axiom Total Ankle System Regulation Number: 21 CFR 888.3110 Regulation Name: Ankle Joint Metal/Polymer Semi-Constrained Cemented Prosthesis Regulatory Class: Class II Product Code: HSN Dated: September 13, 2023 Received: September 13, 2023
Dear Brianna Prindle:
We have reviewed your section 510(k) premarket notification of intent to market the device referenced above and have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to legally marketed predicate devices marketed in interstate commerce prior to May 28, 1976, the enactment date of the Medical Device Amendments, or to devices that have been reclassified in accordance with the provisions of the Federal Food, Drug, and Cosmetic Act (the Act) that do not require approval of a premarket approval application (PMA). You may, therefore, market the device, subject to the general controls provisions of the Act. Although this letter refers to your product as a device, please be aware that some cleared products may instead be combination products. The 510(k) Premarket Notification Database available at https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfpmn/pmn.cfm identifies combination product submissions. The general controls provisions of the Act include requirements for annual registration, listing of devices, good manufacturing practice, labeling, and prohibitions against misbranding and adulteration. Please note: CDRH does not evaluate information related to contract liability warranties. We remind you, however, that device labeling must be truthful and not misleading.
If your device is classified (see above) into either class II (Special Controls) or class III (PMA), it may be subject to additional controls. Existing major regulations affecting your device can be found in the Code of Federal Regulations, Title 21, Parts 800 to 898. In addition, FDA may publish further announcements concerning your device in the Federal Register.
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Additional information about changes that may require a new premarket notification are provided in the FDA guidance documents entitled "Deciding When to Submit a 510(k) for a Change to an Existing Device" (https://www.fda.gov/media/99812/download) and "Deciding When to Submit a 510(k) for a Software Change to an Existing Device" (https://www.fda.gov/media/99785/download).
Your device is also subject to, among other requirements, the Quality System (QS) regulation (21 CFR Part 820), which includes, but is not limited to, 21 CFR 820.30. Design controls; 21 CFR 820.90. Nonconforming product; and 21 CFR 820.100, Corrective and preventive action. Please note that regardless of whether a change requires premarket review, the QS regulation requires device manufacturers to review and approve changes to device design and production (21 CFR 820.30 and 21 CFR 820.70) and document changes and approvals in the device master record (21 CFR 820.181).
Please be advised that FDA's issuance of a substantial equivalence determination does not mean that FDA has made a determination that your device complies with other requirements of the Act or any Federal statutes and regulations administered by other Federal agencies. You must comply with all the Act's requirements, including, but not limited to: registration and listing (21 CFR Part 807); labeling (21 CFR Part 801); medical device reporting of medical device-related adverse events) (21 CFR Part 803) for devices or postmarketing safety reporting (21 CFR Part 4, Subpart B) for combination products (see https://www.fda.gov/combination-products/guidance-regulatory-information/postmarketing-safety-reportingcombination-products); good manufacturing practice requirements as set forth in the quality systems (QS) regulation (21 CFR Part 820) for devices or current good manufacturing practices (21 CFR Part 4, Subpart A) for combination products; and, if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR Parts 1000-1050.
Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR 807.97). For questions regarding the reporting of adverse events under the MDR regulation (21 CFR Part 803), please go to https://www.fda.gov/medical-device-safety/medical-device-reportingmdr-how-report-medical-device-problems.
For comprehensive regulatory information about mediation-emitting products, including information about labeling regulations, please see Device Advice (https://www.fda.gov/medicaldevices/device-advice-comprehensive-regulatory-assistance) and CDRH Learn (https://www.fda.gov/training-and-continuing-education/cdrh-learn). Additionally, you may contact the Division of Industry and Consumer Education (DICE) to ask a question about a specific regulatory topic. See the DICE website (https://www.fda.gov/medical-device-advice-comprehensive-regulatoryassistance/contact-us-division-industry-and-consumer-education-dice) for more information or contact DICE by email (DICE@fda.hhs.gov) or phone (1-800-638-2041 or 301-796-7100).
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Sincerely,
# Lixin Liu -S
Lixin Liu, Ph.D. Assistant Director DHT6A: Division of Joint Arthroplasty Devices OHT6: Office of Orthopedic Devices Office of Product Evaluation and Quality Center for Devices and Radiological Health
Enclosure
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# Indications for Use
Submission Number (if known)
K232595
Device Name
Kinos Axiom Total Ankle System
#### Indications for Use (Describe)
The Kinos Axiom Total Ankle System is indicated for patients with ankle joints damaged by severe rheumatoid, posttraumatic, or degenerative arthritis. The Kinos Total Ankle System is additionally indicated for patients with failed previous ankle surgery. The Kinos Axiom Total Ankle System is intended for cement use only.
Type of Use (Select one or both, as applicable)
> Prescription Use (Part 21 CFR 801 Subpart D)
Over-The-Counter Use (21 CFR 801 Subpart C)
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K232595 Page 1 of 3
Image /page/4/Picture/1 description: The image shows the word "restor3d" in a bold, sans-serif font. The first part of the word, "restor", is filled in with black, while the "3d" part is outlined in black. The letters are evenly spaced and the overall design is clean and modern. The image appears to be a logo or branding element.
# 510(k) Summary
Date Prepared: November 26th, 2023
In accordance with the requirements of 21 CFR 807.92, this information serves as a Summary of Safety and Effectiveness for the use of the Kinos Axiom Total Ankle System.
#### A. 510(k) Sponsor:
restor3d, inc. 4001 E. NC 54 Highway, Suite 3160 Durham, North Carolina, 27709
### B. Primary Correspondent:
Brianna Prindle Head of Regulatory (786) 521-0501 (direct) brianna@restor3d.com
#### C. Premarket Notification:
| Trade Name: | Kinos Axiom Total Ankle System |
|----------------------|----------------------------------------------------------------|
| Common Name: | Total Ankle Replacement |
| Classification Name: | Ankle joint metal/polymer semi-constrained cemented prosthesis |
| Regulation Number: | 21 CFR 888.3110 |
| Product Code: | HSN |
| Classification: | II |
| Review Panel: | Orthopedic |
#### D. Indications for Use:
The Kinos Axiom Total Ankle System is indicated for patients with ankle joints damaged by severe rheumatoid, post-traumatic, or degenerative arthritis. The Kinos Total Ankle System is additionally indicated for patients with failed previous ankle surgery. The Kinos Axiom Total Ankle System is intended for cement use only.
#### E. Predicate Devices:
The Kinos Axiom Total Ankle System is substantially equivalent to the following devices:
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| 510(k) | Trade Name | Manufacturer |
|----------------------------|--------------------------------------------------|--------------------------------------------------|
| Primary Predicate Device | | |
| K192778 | Kinos Axiom Total Ankle System | Restor3d, Inc.<br>Cleared under Kinos<br>Medical |
| Secondary Predicate Device | | |
| K140749 | Infinity Total Ankle System | Wright Medical |
| Reference Device | | |
| K220523 | restor3d TiDAL Lumbar Interbody<br>Fusion Device | restor3d, Inc. |
| K210390 | Apex 3D Total Ankle Replacement<br>System | Paragon 28, Inc. |
# F. Device Description:
The subject Kinos Axiom Total Ankle System is an implant and instrument system designed to preserve motion in patients with ankle arthritis or previously failed ankle surgery. The device is a fixed bearing and semi-constrained implant construct, intended for replacement of the articulating surfaces of the ankle that have been affected by a disease state or injury. The device provides limited mobility to a patient by restoring alignment of the articulating surfaces, reducing pain, and providing flexion-extension movement within the ankle joint. The device is intended to be used with bone cement. The subject Kinos Axiom Total Ankle System consists of three implant components - a tibial implant affixed to the tibia, a bearing implant assembled to the tibial implant and a talar implant affixed to the tibial implant and bearing implant, assembled intraoperatively, function together and articulate with the talar implant to create a fixed bearing prosthesis, replacing the articulating surface of the tibial-talar joint. The subject line extension tibial implant is additively manufactured from Ti-6A1-4V (ASTM F2924) and features a modified stem for fixation into the tibia.
# G. Performance Testing:
The modified device was subjected to the following performance testing and/or analyses to establish substantial equivalence in comparison to the predicate device.
- O Strength Testing per ASTM F2665
- O Bone Stability Testing
- Porous Surface Characterization O
- 0 Biocompatibility per ISO 10993-1:2018
#### H. Substantial Equivalence Comparison:
Substantial equivalence of the line extension tibial implant to the predicate device is based on the following:
- The line extension tibial implant and predicate device have the same ● indications for use and the same intended use.
- The line extension tibial implant and predicate device share similar ●
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performance characteristics, design, and sizes (dimensions are comparable to those offered by predicate systems).
- Changes in technological characteristics, including material and o manufacturing methods, are not shown to raise any different questions of safety or effectiveness.
# I. Conclusion:
Based on comparison of the intended use, indications for use and technological characteristics, the subject Kinos Axiom Total System is substantially equivalent to the predicate Kinos Axiom Total Ankle System. The change in material specification to ASTM F2924 for the addition of additive manufacturing, minor changes in dimensions and sizes and changes in technological characteristics do not raise any different questions of safety or effectiveness.
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Part 2 — Embeddings: the galaxy map 3 min
1. Search: exact and fuzzy
Type a phrase like "coronary artery calcification" into the search box. You get two kinds of results. Exact results match the literal phrase — prefix searches work ("coronary artery calcificati") but suffix searches do not. Fuzzy results match on the meaning and intent of your phrase rather than the exact words, and are sorted by relevance score. Hover over the Exact or Fuzzy badge on any row to see exactly why it matched.
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Exact matches on the literal phrase (prefix search works, suffix does not). Fuzzy matches on the meaning and intent of the phrase rather than the exact words. Hover over the badge on any row to see why it matched.
You search "coronary artery calcification" and want only software devices with AI. What two filters do you apply?
Narrow by SaMD (software-only devices), then narrow by AI/ML (devices with AI).
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Scroll right in the results table. The intended use is extracted for you — no need to open the PDF. The device story gives a high-level snapshot of what the device does and how it's used. The AI Performance sub-table shows each output name, acceptance criteria, observed values, and development/test dataset descriptions — the same format Innolitics uses for regulatory strategy outputs, and the fastest high-level fingerprint of an AI device. It is AI-generated but has been very reliable in practice.
Where do you find a device's intended use without opening the PDF?
Scroll right in the search results table. The intended use column is extracted for you; no need to dig into the 510(k) summary PDF.
What does the AI Performance sub-table show, and why is it useful?
Output name, acceptance criteria, observed values, development dataset description, and test dataset description. It's the same format we use for regulatory strategy output and Fast 510(k) input, and the fastest high-level fingerprint of an AI device. AI-generated but reliable in practice.
3. Judging fuzzy relevance
Fuzzy results trail off in relevance as you scroll. Use three signals to decide how far down to go: the fuzzy badge explanations, the intended use column, and whether your target output (e.g., Cobb angle) still appears in the AI Performance sub-table. Once it stops appearing, you're past the relevant zone. A top hit with a low score (~0.4) and a stretched explanation is a hint the closest predicates are far away — the project may be headed for De Novo. Note the fuzzy search is a pattern match: it doesn't handle negation ("not") well, and hardware devices can appear — filter by SaMD/AI ML to cut them.
How do you judge how far down fuzzy search results to go?
Use the relevancy signals: the fuzzy badge explanations, the intended use column, and whether the target output (e.g., Cobb angle) still appears in the AI Performance sub-table. Once it stops appearing, results are trailing off in relevancy.
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Reading rule for every project: how many summaries do you read in full?
At least the three most relevant 510(k) or De Novo summaries, in full. After that, use targeted chat questions to confirm your memory quickly. The tool supports this professional habit — it doesn't replace it.
5. Side-by-side comparison
Select multiple rows in the results table (aim for under ~10), then open the PDF Viewer tab. Ask one question — it goes to all selected devices in parallel, each with citations. This is the fastest way to compare and contrast devices: training data, PCCP scope, how they handled adding new scanners, and so on.
What does the side-by-side PDF viewer mode do?
Select multiple devices, open the PDF viewer tab, and ask one question (e.g., "Describe the training data"). It queries all selected devices simultaneously with citations, so you can compare and contrast quickly.
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With rows selected, go to the Collections tab and create a labeled collection (e.g., "Cobb Angle Project"). Reload that selection any time — before a client call, pull up the collection and ask questions across all of its devices at once.
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What can you do from the regulations tree view?
Browse product codes and regulation numbers, read the identification text and special controls, browse sibling product codes, open device PDFs on the right, and search by product code or regulation number at the top of the tree.
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Click Show Chart and segment by regulation number (or product code) to see which regulations dominate your result set. Clicking a regulation takes you into the regulations tree. Great for spotting that most matches are, say, hardware laparoscopic devices — a cue to go back and filter.
How do you see which regulations dominate a search result set?
Click "Show Chart" and segment by Regulation Number. Clicking a regulation takes you to the regulations tree.
9. The predicate graph
Open the Predicates tab for a family-tree view of predicate relationships. Click a node to trace its parents and children; selections from search carry over pre-selected. Commonly predicated devices are worth reading — a lot of people predicated them for a reason. The visual lineage is also handy on client calls, e.g. to show how a predicate family evolved and justify why your predicate still holds.
In the predicate graph, why are commonly predicated devices worth reading?
A lot of people predicated them for a reason. Clicking a node traces parents and children, and selections from search carry over pre-selected.
10. Embeddings: the galaxy map
The Embeddings tab plots every matching document in a 2-D "galaxy map" where semantically similar devices cluster together. Hover or click clusters to explore, and let AI label the clusters for you. Embeddings beat product codes for grouping: two devices can carry different product codes (LLZ vs. QIH) yet do the same thing — the embedding captures the meaning of the intended use and device story. This is also exactly how retrieval-augmented generation (RAG) works under the hood, and it makes a great visual on client calls.
Try it yourself
Head to the search page and work through a few of these AI/ML fuzzy searches to build intuition: perivascular fat on CT · aortic valve calcification opportunistic screening on noncontrast CT · breast cancer prediction on digital pathology slides · autism detection · gestational age prediction · a hearing aid that can also detect a pulse · foundation model based analysis of ECG · large language models · penetration test. Watch how the relevance scores, intended use, and AI Performance tables tell you when results stop being meaningful.