MOTO Medial, MOTO Lateral and MOTO Sphere Partial Knee System is designed for cemented use in partial knee arthroplasty, if there is evidence of sufficient sound bone to seat and support the components. Partial replacement of the articulating surfaces of the knee is indicated when only one compartment of the joint is affected due to the compartmental primary degenerative or post-traumatic degenerative disease, previous tibial condyle or plateau fractures, deformity or revision of previous arthroplasty.
Device Story
MOTO Partial Knee System Extension comprises implantable Co-Cr-Mo femoral components (MOTO Sphere) and E-cross (UHMWPE + Vitamin E) tibial inserts; intended for cemented partial knee arthroplasty. Femoral components available in 5 sizes, with optional TiNbN coating; inserts available in 8 sizes (7mm thickness). Devices replace articulating surfaces of medial or lateral knee compartment. Used in clinical settings by orthopedic surgeons. Output is physical restoration of joint surface; aids in correcting deformity and managing degenerative disease. Benefits include improved range of motion and joint function. System components are sterile, single-use, and implanted via standard orthopedic surgical techniques.
Clinical Evidence
No clinical studies were conducted. Substantial equivalence is supported by non-clinical bench testing, including fatigue endurance, contact pressure/area (ISO 21536), range of motion (ISO 21536, ASTM F2083-21), wear behavior (ISO 14243-1/2), and biocompatibility assessments.
Technological Characteristics
Materials: Co-Cr-Mo (ISO 5832-4) and E-cross (Vitamin E crosslinked UHMWPE). Optional TiNbN coating. Fixation: Cemented. Components: Femoral (5 sizes) and tibial inserts (8 sizes, 7mm thickness). Sterilization: Sterile, single-use. No software or electronic components.
Indications for Use
Indicated for patients requiring partial knee arthroplasty due to primary or post-traumatic degenerative disease, previous tibial condyle/plateau fractures, deformity, or revision of previous arthroplasty, where only one compartment is affected and sufficient sound bone exists to support components.
Regulatory Classification
Identification
A knee joint femorotibial metal/polymer non-constrained cemented prosthesis is a device intended to be implanted to replace part of a knee joint. The device limits minimally (less than normal anatomic constraints) translation in one or more planes. It has no linkage across-the-joint. This generic type of device includes prostheses that have a femoral condylar resurfacing component or components made of alloys, such as cobalt-chromium-molybdenum, and a tibial component or components made of ultra-high molecular weight polyethylene and are intended for use with bone cement (§ 888.3027).
Predicate Devices
MOTO Partial Knee & MOTO PFJ Systems Extension (K213071)
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FDA U.S. FOOD & DRUG ADMINISTRATION
July 24, 2025
Medacta International S.A.
Christopher Lussier
Senior Director, Quality and Regulatory
Medacta USA
6386 Global Drive, Suite 101
Memphis, Tennessee 38141
Re: K251618
Trade/Device Name: MOTO Partial Knee System Extension
Regulation Number: 21 CFR 888.3520
Regulation Name: Knee Joint Femorotibial Metal/Polymer Non-Constrained Cemented Prosthesis
Regulatory Class: Class II
Product Code: HSX
Dated: May 27, 2025
Received: May 27, 2025
Dear Christopher Lussier:
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.
U.S. Food & Drug Administration
10903 New Hampshire Avenue
Silver Spring, MD 20993
www.fda.gov
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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 (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-reporting-combination-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.
All medical devices, including Class I and unclassified devices and combination product device constituent parts are required to be in compliance with the final Unique Device Identification System rule ("UDI Rule"). The UDI Rule requires, among other things, that a device bear a unique device identifier (UDI) on its label and package (21 CFR 801.20(a)) unless an exception or alternative applies (21 CFR 801.20(b)) and that the dates on the device label be formatted in accordance with 21 CFR 801.18. The UDI Rule (21 CFR 830.300(a) and 830.320(b)) also requires that certain information be submitted to the Global Unique Device Identification Database (GUDID) (21 CFR Part 830 Subpart E). For additional information on these requirements, please see the UDI System webpage at https://www.fda.gov/medical-devices/device-advice-comprehensive-regulatory-assistance/unique-device-identification-system-udi-system.
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-devices/medical-device-safety/medical-device-reporting-mdr-how-report-medical-device-problems.
For comprehensive regulatory information about medical devices and radiation-emitting products, including information about labeling regulations, please see Device Advice (https://www.fda.gov/medical-devices/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-devices/device-advice-comprehensive-regulatory-
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assistance/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).
Sincerely,
Peter G. Allen
-S
Digitally signed by Peter G. Allen -S
Date: 2025.07.24 15:41:29
-04'00"
For 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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FORM FDA 3881 (8/23)
Page 1 of 1
PSC Publishing Services (301) 443-6740
EF
| DEPARTMENT OF HEALTH AND HUMAN SERVICES Food and Drug Administration Indications for Use | Form Approved: OMB No. 0910-0120 Expiration Date: 07/31/2026 See PRA Statement below. |
| --- | --- |
| 510(k) Number (if known) K251618 | |
| Device Name MOTO Partial Knee System Extension | |
| Indications for Use (Describe) MOTO Medial, MOTO Lateral and MOTO Sphere Partial Knee System is designed for cemented use in partial knee arthroplasty, if there is evidence of sufficient sound bone to seat and support the components. Partial replacement of the articulating surfaces of the knee is indicated when only one compartment of the joint is affected due to the compartmental primary degenerative or post-traumatic degenerative disease, previous tibial condyle or plateau fractures, deformity or revision of previous arthroplasty. | |
| 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) | |
| CONTINUE ON A SEPARATE PAGE IF NEEDED. | |
| This section applies only to requirements of the Paperwork Reduction Act of 1995. *DO NOT SEND YOUR COMPLETED FORM TO THE PRA STAFF EMAIL ADDRESS BELOW.* | |
| The burden time for this collection of information is estimated to average 79 hours per response, including the time to review instructions, search existing data sources, gather and maintain the data needed and complete and review the collection of information. Send comments regarding this burden estimate or any other aspect of this information collection, including suggestions for reducing this burden, to: Department of Health and Human Services Food and Drug Administration Office of Chief Information Officer Paperwork Reduction Act (PRA) Staff PRAStaff@fda.hhs.gov | |
| "An agency may not conduct or sponsor, and a person is not required to respond to, a collection of information unless it displays a currently valid OMB number." | |
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K251618 Page 1 of 4
MOTO Partial Knee System Extension
Traditional
510(k)
Medacta International SA
# 510(k) Summary
## I. Submitter
Medacta International SA
Strada Regina
6874 Castel San Pietro (CH)
Switzerland
Phone (+41) 91 696 60 60
Fax (+41) 91 696 60 66
Contact Person: Stefano Baj, Regulatory and Compliance Director, Medacta International SA
Applicant Correspondent: Chris Lussier, Senior Director, Quality and Regulatory, Medacta USA
Date Prepared: May 27, 2025
Date Revised: July 23, 2025
## II. Device
| Device Proprietary Name: | MOTO Partial Knee System Extension |
| --- | --- |
| Common or Usual Name: | Unicompartmental Knee Prosthesis |
| Classification Name: | Knee joint femorotibial metal/polymer non-constrained cemented prosthesis |
| Primary Product Code | HSX |
| Regulation Number: | 21 CFR 888.3520 |
| Device Classification | II |
## III. Predicate Device
Substantial equivalence is claimed to the following predicate devices.
Primary Predicate device:
- MOTO Partial Knee & MOTO PFJ Systems Extension, K213071, Medacta International SA
Additional Predicate devices:
- Oxford® Fixed Lateral Bearing Partial Knee Replacement, K133940, Biomet UK, Ltd
- MOTO Partial Knee System, K162084, Medacta International SA
- MOTO Lateral Partial Knee System, K183029, Medacta International SA
Reference device:
- GMK Total Knee System - TiNbN Coating, K202684, Medacta International SA
## IV. Device Description
The MOTO Partial Knee System Extension is a Medacta partial knee prosthesis portfolio extension including implantable devices, provided individually packed, sterile and single-use. Specifically, the purpose of this submission is to gain the clearance for:
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MOTO Partial Knee System Extension
Traditional 510(k)
Medacta International SA
K251618 Page 2 of 4
- MOTO Sphere femoral components, made of Co-Cr-Mo according to ISO 5832-4 and available in 5 sizes with or without TiNbN coating. They are intended to replace the medial or lateral femoral compartment of the natural knee joint and must be implanted in combination with the tibial component of MOTO Medial or MOTO Lateral (K162084, K183029 and K213071);
- 7mm thick MOTO Medial and MOTO Lateral inserts fixed made of E-cross, available in 8 sizes and intended to be coupled with the subject MOTO Sphere femoral components as well as MOTO Medial or MOTO Lateral tibial components (K162084, K183029 and K213071).
# V. Indications for Use
MOTO Medial, MOTO Lateral and MOTO Sphere Partial Knee System is designed for cemented use in partial knee arthroplasty, if there is evidence of sufficient sound bone to seat and support the components. Partial replacement of the articulating surfaces of the knee is indicated when only one compartment of the joint is affected due to the compartmental primary degenerative or post-traumatic degenerative disease, previous tibial condyle or plateau fractures, deformity or revision of previous arthroplasty.
# VI. Comparison of Technological Characteristics
- **MOTO Sphere femoral components**
The subject MOTO Sphere femoral components and the predicate Oxford® Fixed Lateral Bearing Partial Knee Replacement (K133940) are substantially equivalent with respect to the following characteristics:
- Sizes;
- Configuration;
- Design;
- Femoral curvature;
- Fixation;
- Material;
- Biocompatibility;
- Device usage;
- Packaging;
- Shelf-life; and
- Sterilization.
The subject MOTO Sphere femoral components differ from the predicate Oxford® Fixed Lateral Bearing Partial Knee Replacement (K133940) with respect to:
- Coverage; and
- Coating.
- **E-cross MOTO Medial and MOTO Lateral inserts fixed**
The subject 7mm thick E-cross MOTO Medial and MOTO Lateral inserts fixed and the predicate devices (K213071) are substantially equivalent with respect to the following characteristics:
- Sizes;
- Fixation to the baseplate;
- Material;
- Biocompatibility;
- Device usage;
- Packaging;
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MOTO Partial Knee System Extension
Traditional 510(k)
Medacta International SA
K251618 Page 3 of 4
- Shelf-life; and
- Sterilization.
The only difference between the subject 7mm thick E-cross MOTO Medial and MOTO Lateral inserts fixed and the predicate devices (K213071) is the thickness.
## Discussion
The coverage of the subject MOTO Sphere is substantially equivalent to the one of the Oxford® Fixed Lateral Bearing Partial Knee Replacement (K133940). The AP and PD dimensions of the subject devices have been designed slightly increased in larger sizes with respect to the ones of the predicate devices (K133940) in order to increase the range of motion thus this difference does not affect safety and effectiveness.
MOTO Sphere TiNbN coated version does not raise any different questions of safety and effectiveness since it is the same coating as Medacta predicate devices (K213071).
The new thickness of the subject devices has been designed to cover a larger intended population with respect to the predicate devices (K213071), but it does not introduce different questions of safety and effectiveness as demonstrated by performance testing.
The comparison of technological characteristics and performance data provided within the submission supports the substantial equivalence of the subject devices respect to the predicate devices.
## VII. Performance Data
Based on the risk analysis, testing activities were conducted to written protocols. The following evaluations and tests are provided in support of the substantial equivalence determination.
## Non-Clinical Studies
### PERFORMANCE TESTING
- Fatigue endurance test of the posterior condyle
- Contact pressures and areas according to ISO 21536
- Comparative dimensional evaluation of the MOTO Sphere femoral component
- MOTO Sphere femoral component - Cementation area
- MOTO Sphere femoral component - Range of Motion according to ISO 21536 and ASTM F2083-21
- TiNbN coated MOTO femoral components - Wear behaviour
- MOTO Partial knee system medial and lateral tibial insert made of UHMWPE + Vitamin E crosslinked: wear test in knee simulator machine with load control according to ISO 14243-1 and ISO 14243-2
- Thickness 7mm E-Cross MOTO Tibial Inserts - Comparison to the MOTO range of products
### PYROGENICITY
- Bacterial endotoxin test (LAL test) according to European Pharmacopoeia §2.6.14 (which is equivalent to USP chapter <85>)
- Pyrogen test according to USP chapter <151> for pyrogenicity determination
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MOTO Partial Knee System Extension
Traditional 510(k)
Medacta International SA
- The subject devices are not labeled as non-pyrogenic or pyrogen free.
- BIOCOMPATIBILITY assessment
- SHELF-LIFE evaluation
Clinical Studies:
- No clinical studies were conducted.
VIII. Conclusion
The information provided above supports that the subject devices are substantially equivalent to the predicate devices.
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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.
Use the checkboxes above the results to narrow: SaMD keeps only software-only devices, AI / ML keeps only devices with AI.
Exact vs. fuzzy search: what's the difference?
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).
2. The results table
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.
4. Device detail page: chat and citations
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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.
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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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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.