The WMT Modular Ulnar Head Implant is indicated for the following indications : - Replacement of the distal ulnar head for disorders of the distal radioulnar joint . in rheumatoid, degenerative and post-traumatic arthritis presenting with the following findings: - -pain and weakness of the wrist joint not improved by nonoperative treatment; - -instability of the ulnar head with radiographic evidence of dislocation or erosive changes of the distal radioulnar joint; - -failed ulnar head resection; e.g. Darrach resection - Primary replacement after fracture of the ulnar head or neck. . - . Revision following failed ulnar head arthroplasty.
Device Story
WMT Modular Ulnar Head Implant is a prosthetic device for distal ulnar head replacement. It consists of a modular cobalt chrome head and a titanium alloy stem. The design addresses non-axisymmetric distal ulna anatomy by providing an offset between the head and stem to replicate normal joint kinematics. The device is implanted by a surgeon in a clinical setting. It features a locking taper mechanism for assembly and suture holes for soft tissue attachment. Fixation can be achieved via cement or uncemented techniques. By replacing the damaged or unstable ulnar head, the device aims to restore joint function, reduce pain, and improve stability in the wrist joint.
Clinical Evidence
Bench testing only.
Technological Characteristics
Modular prosthesis. Head: Cobalt chrome (ASTM F799 or F1537) with plasma-sprayed lateral surface and polished articulating surface. Stem: Titanium alloy (ASTM F136) with fluted design and grit-blast finish. Locking taper mechanism. Sizes: 16-22mm head diameter, 8-11mm height, 1.5-3mm offset. Stems available in standard (4.5° taper) and revision (1° taper) options. Fixation: Cemented or uncemented.
Indications for Use
Indicated for patients with rheumatoid, degenerative, or post-traumatic arthritis of the distal radioulnar joint experiencing pain, weakness, or instability; patients with failed ulnar head resection; patients requiring primary replacement after ulnar head/neck fracture; and patients requiring revision after failed ulnar head arthroplasty.
Regulatory Classification
Identification
A wrist joint ulnar (hemi-wrist) polymer prosthesis is a mushroom-shaped device made of a medical grade silicone elastomer or ultra-high molecular weight polyethylene intended to be implanted into the intramedullary canal of the bone and held in place by a suture. Its purpose is to cover the resected end of the distal ulna to control bone overgrowth and to provide an articular surface for the radius and carpus.
Predicate Devices
Avanta uHead™ modular ulnar head implant (K010786)
Reference Devices
DCW/WMT Swanson silicone ulnar head implant
Submission Summary (Full Text)
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Q20274
page 1 of 3
Image /page/0/Picture/2 description: The image shows the logo for Wright Medical Technology, Inc. The logo features a stylized "W" on the left, followed by the company name in bold, uppercase letters. Below the name, the address "5677 Airline Road, Arlington, TN 38002" and the phone number "901-867-9971" are printed.
FEB 2 2 2002
# 510(K) SUMMARY OF SAFETY AND EFFECTIVENESS
In accordance with the Food and Drug Administration Rule to implement provisions of the Safe Medical Devices Act of 1990 and in conformance with 21 CRF 807, this information serves as a Summary of Safety and Effectiveness for the use of the WMT MODULAR ULNAR HEAD.
| Submitted By: | Wright Medical Technology, Inc. |
|-------------------------------------|---------------------------------------------------------------|
| Date: | January 25, 2002 |
| Contact Person: | Ehab M. Esmail<br>Manager, Regulatory Affairs |
| Proprietary Name: | WMT MODULAR ULNAR HEAD |
| Common Name: | ULNAR HEAD IMPLANT |
| Classification Name and Reference: | 21 CFR 888.3810 Prosthesis, WRIST, HEMI-,<br>ULNAR - Class II |
| Device Product Code and Panel Code: | Orthopedics/87/KXE |
### DEVICE INFORMATION
### A. INTENDED USE
The WMT Modular Ulnar Head Implant is indicated for the following indications :
- Replacement of the distal ulnar head for disorders of the distal radioulnar joint . in rheumatoid, degenerative and post-traumatic arthritis presenting with the following findings:
- -pain and weakness of the wrist joint not improved by nonoperative treatment;
- -instability of the ulnar head with radiographic evidence of dislocation or erosive changes of the distal radioulnar joint;
- -failed ulnar head resection; e.g. Darrach resection
- Primary replacement after fracture of the ulnar head or neck. .
- . Revision following failed ulnar head arthroplasty.
Image /page/0/Picture/16 description: The image shows the logo for Wright Medical Technology, Inc. The logo features a stylized "W" symbol above the word "WRIGHT" in a bold, sans-serif font. Below "WRIGHT" are the words "MEDICAL TECHNOLOGY, INC." in a smaller, sans-serif font, with a line underneath.
Image /page/0/Picture/17 description: The image shows a black and white drawing of a globe. The globe is tilted on its axis and is sitting on a stand. The continents of Asia and Australia are visible on the globe. The image is simple and does not contain any other objects or details.
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WMT Modular Ulnar Head Implant 510(K) SUMMARY Page 2 of 3
020274
page 2 of 3
#### B. DEVICE DESCRIPTION
The design features of the WMT Modular Ulnar Head Implant (Figure 1) is substantially equivalent to the Avanta uHead™ modular ulnar head implant (previously submitted and cleared under AVANTA ULNAR HEAD IMPLANT -- 510(k): K010786).
Image /page/1/Figure/5 description: The image shows two different types of medical technology, Wright Medical Technology and AVANTA. Each technology has a standard stem, a head, and a revision stem. The Wright Medical Technology components are shown in black, while the AVANTA components are shown in gray. The image provides a visual comparison of the components of the two technologies.
Figure 1 - Comparison Between WMT and Avanta uHead™ modular ulnar head implants
The WMT Modular Ulnar Head Implant was designed as a more anatomic alternative to the previously submitted and cleared Avanta uHead™ modular ulnar head implant (previously submitted and cleared under AVANTA ULNAR HEAD IMPLANT – 510(k): K010786) that utilizes axisymmetric head and stem components. The anatomy of the distal ulna is not axisymmetric, but rather consists of a head that is offset medial-lateral and dorsal-volar from the ulnar canal. Cadaveric analysis has shown that there is no correlation between head and stem location, thus a system where the head is offset relative to the stem is required to replicate normal anatomy and thus, joint kinematics.
The WMT Modular Ulnar Head is manufactured from cobalt chrome (ASTM F799 or F1537). The triangulated head will have a highly polished exterior surface across the articulating arc and distal surface, and will have a plasma sprayed textured surface laterally for tissue adhesion. The heads will be available in sizes ranging from 16mm to 22mm in diameter, 8mm to 11mm in height, and 1.5mm to 3mm in offset. The WMT Modular Ulnar Head Implant will contain suture holes for attaching soft tissues and a locking taper mechanism for engaging the modular head onto the stem.
The WMT Modular Ulnar Stem is manufactured from titanium (ASTM F136). The stems will be available in a standard and revision option: the standard stem will be tapered 4.5° to match the anatomical canal geometry while the revision stem will have a 1º taper to match proximal canal geometry. Each stem option will be available in distal diameters ranging from 5.5mm to 8mm and in two lengths: a standard length will have a 1mm platform and 25mm stem, and the extended length will have a 20mm platform and a
Image /page/1/Picture/11 description: The image shows the logo for Wright Medical Technology, Inc. The logo features a stylized "W" above the word "WRIGHT" in a bold, serif typeface. Below "WRIGHT" is the phrase "MEDICAL TECHNOLOGY, INC." in a smaller, sans-serif font. The overall design is simple and professional.
Image /page/1/Picture/12 description: The image shows a black and white drawing of a globe. The globe is sitting on a stand. The continents of Asia and Australia are visible on the globe.
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K020a74
Page 3 of 3
50mm stem. The stems will be fluted and will have a heavy grit blast finish over entire part except for the taper.
Table 1 is a comparison chart summarizing the above design features for the WMT modular ulnar head implant, the Avanta uHead™ modular ulnar head implant and DCW/WMT Swanson silicone ulnar head implant.
| Attribute | WMT modular ulnar<br>head implant | Avanta uHead™<br>modular ulnar head<br>implant | DCW/WMT<br>Swanson silicone<br>ulnar head implant |
|-------------------------|------------------------------------------------------------------------------------------------|-------------------------------------------------------------|---------------------------------------------------|
| Sizes | 8 heads, 6 stems | 3 stems, 3 heads | 7 |
| Modularity | Yes | Yes | No |
| Locking Mechanism | Taper | Taper | N/A |
| Material<br>(head/stem) | Head: CoCr (ASTM<br>F1537 or F799) with<br>plasma spray<br>Stem: titanium alloy<br>(ASTM F136) | Head: CoCr (ASTM<br>F1537, F75 or F799)<br>Stem: CpTi (F67) | Silicone |
| Suture Attachments | Yes | Yes | Yes |
| Bone Fixation | Cement or Uncemented | Cement or Uncemented | |
| Indications | Same | Same | Same |
Table 1 - Comparison between WMT modular ulnar head implant, the Avanta uHead™ modular ulnar head implant and DCW/WMT Swanson silicone ulnar head implant
## C. SUBSTANTIAL EQUIVALENCE INFORMATION
The intended use, material, type of interface, and design features of the WMT Modular Ulnar Head Implant are substantially equivalent to the Avanta uHead™ modular ulnar head implant (previously submitted and cleared under AVANTA ULNAR HEAD IMPLANT - 510(k): K010786). The safety and effectiveness of the WMT Modular Ulnar Head Implant are adequately supported by the substantial equivalence information, materials data, and testing results provided within this Premarket Notification.
Image /page/2/Picture/10 description: The image shows a black and white globe. The globe is tilted on a stand. The continents of Asia and Australia are visible on the globe.
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Image /page/3/Picture/1 description: The image is a black and white logo for the U.S. Department of Health & Human Services. The logo features a stylized eagle with its head turned to the left and its wings outstretched. The eagle is composed of three thick, curved lines. The words "DEPARTMENT OF HEALTH & HUMAN SERVICES - USA" are arranged in a circular pattern around the eagle.
Food and Drug Administration 9200 Corporate Boulevard Rockville MD 20850
# FEB 2 2 2002
Mr. Ehab M. Esmail Manager, Regulatory Affairs Wright Medical Technology, Inc. 5677 Airline Road Arlington, Tennessee 38002
Re: K020274
K02027 |
Trade Name: WMT Modular Ulnar Head Implant Regulatory Number: 888.3810 Regulatory Number: 888.3610
Regulation Name: Single/multiple component metallic bone fixation fasten Single/multiple component included metallic bone fixation fastener Regulatory Class: II Product Code: KXE Dated: January 25, 2002 Received: January 28, 2002
Dear Mr. Esmail:
We have reviewed your Section 510(k) premarket notification of intent to market the device We have reviewed your Sectori 910(x) premained in substantially equivalent (for the indications
referenced above and have determined the device is substantially interstate referenced above and nave determined the devices devices marketed in interstate for use stated in the enclosure) to regally manced provided Device Amendments, or to
commerce prior to May 28, 1976, the enactment date of the Federal Food. Drug commerce prior to May 20, 1970, the chaomic with the provisions of the Federal Food, Drug, devices that have been reciassified in accordance what approval application (PMA).
and Cosmetic Act (Act) that do not require approval of a provisions of the Act and Cosmetic Act (Act) that do not require as or everal controls provisions of the Act.
You may, therefore, market the device, subject to the general registretion, listing You may, therefore, market the device, subject to are stimments for annual registration, listing of
The general controls provisions of the Act include requirements for annual The general controls provisions of the Act life. Include required in the branding and adulteration.
If your device is classified (see above) into either class II (Special Controls) or class III (PMA), it If your device is classifica (see above) into Existing major regulations affecting your device can
may be subject to such additional controls. Existing major and dition EDA may be subject to such additional controller "Extoning thing on to 898. In addition, FDA may be found in the Code of Pouchal Linger in the Federal Register.
Please be advised that FDA's issuance of a substantial equivalence determination does not mean Please be advised that IDA's issualice of a succession a such other requirements of the Act
that FDA has made a determination that your device complies with other must that FDA has made a determination administered by other Federal agencies. You must or any Federal Statutes and regulations annuding, but not limited to: registration and listing (21 CFR Part 807); labeling (21 CFR Part 801); good manufacturing practice requirements as set and CFK Part 807), labeling (21 OFR Part 820); and if applicable, the electronic forth in the quanty systems (QD) regulations (Sections 531-542 of the Act); 21 CFR 1000-1050.
product radiation control provisions (Sections 531-542 of the Act); 21 CFR 1000
{4}------------------------------------------------
Page 2 - Mr. Ehab M. Esmail
This letter will allow you to begin marketing your device as described in your Section 510(k) I ins icher will anow you to ough maing of substantial equivalence of your device to a legally premarket notication: "The PDF mixing of casification for your device and thus, permits your device to proceed to the market.
If you desire specific advice for your device on our labeling regulation (21 CFR Part 801 and II you desire specific advice for you invitro diagnostic devices), please contact the Office of additionally 21 CHC Full 007.10 Internally, for questions on the promotion and advertising of Compliance at (301) 274-4657. Tidationally, be questions of (301) 594-4639. Also, please note the your device, prease ochiave and other reference to premarket notification™ (21CFR Part 807.97). Other general information on your responsibilities under the Act may be obtained from the Other general information on your respeational and Consumer Assistance at its toll-free number (800) 638-2041 or (301) 443-6597 or at its Internet address http://www.fda.gov/cdrh/dsma/dsmamain.html
Sincerely yours,
L. Mula M Mula
Celia M. Witten, Ph.D., M.D. Director Division of General, Restorative and Neurological Devices Office of Device Evaluation Center for Devices and Radiological Health
Enclosure
{5}------------------------------------------------
## WMT Modular Ulnar Head Implant
### INDICATIONS STATEMENT
The WMT Modular Ulnar Head Implant is indicated for the following indications:
- Replacement of the distal ulnar head for disorders of the distal radioulnar . joint in rheumatoid, degenerative and post-traumatic arthritis presenting with the following findings:
- -pain and weakness of the wrist joint not improved by nonoperative treatment;
- -instability of the ulnar head with radiographic evidence of dislocation or erosive changes of the distal radioulnar joint;
- -failed ulnar head resection; e.g. Darrach resection
- Primary replacement after fracture of the ulnar head or neck. .
- Revision following failed ulnar head arthroplasty. ●
#### (PLEASE DO NOT WRITE BELOW THIS LINE - CONTINUE ON ANOTHER PAGE IF NEEDED)
Concurrence of CDRH, Office of Device Evaluation (ODE)
OR
(Division Sign-Off) Division of General Restorative Devices 510(k) Number
> Over-The Counter Use (Optional Format 1-2-96)
Prescription Use (Per21 CFR 801.109)
Mark N. Millerson
(Division Sign-Off) Division of General, Restorative and Neurological Devices
510(k) Number.
Image /page/5/Picture/20 description: The image shows the Wright Medical Technology logo. The logo consists of a large, stylized letter "W" on the left, followed by the words "WRIGHT MEDICAL TECHNOLOGY" stacked on top of each other on the right. Below the logo, there is a line of text that reads "A Wright Medical Group Company".
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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.
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Narrow by SaMD (software-only devices), then narrow by AI/ML (devices with AI).
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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.
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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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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.
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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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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.