K051640 · United Orthopedic Corp. · JWH · Mar 1, 2006 · Orthopedic
Device Facts
Record ID
K051640
Device Name
U2 TOTAL KNEE SYSTEM
Applicant
United Orthopedic Corp.
Product Code
JWH · Orthopedic
Decision Date
Mar 1, 2006
Decision
SESE
Submission Type
Traditional
Regulation
21 CFR 888.3560
Device Class
Class 2
Attributes
Therapeutic
Indications for Use
This device is indicated in knee arthroplasty for reduction or relief of pain and/or improved knee function in skeletally mature patients with severe knee pain and disability due to rheumatoid arthritis, osteoarthritis, primary and secondary traumatic arthritis, polyarthritis, collagen disorders, avascular necrosis of the femoral condyle or pseudogout, posttraumatic loss of joint configuration, particularly when there is patellofemoral erosion, dysfunction or prior patellectomy, moderate valgus, varus, or flexion deformities. This device may also be indicated in the salvage of previously failed surgical attempts if the knee can be satisfactorily balanced and stabilized at the time of surgery. This device system is designed for cemented use only.
Device Story
U2 Total Knee System is a semi-constrained, fixed-bearing, cemented knee prosthesis. Components include Co-Cr-Mo alloy femoral component, Ti-6Al-4V alloy tibial baseplate, and UHMWPE tibial insert and patellar component. Modular snap-fit locking mechanism secures insert to baseplate. Femoral component design mimics natural anatomy to restore rotation, extension, and flexion. Patellar component features dome shape for even stress distribution. Device implanted by orthopedic surgeons in clinical settings to replace damaged knee joints. Benefits include pain reduction, improved joint function, and restoration of joint configuration. System supports cruciate retaining and posterior stabilized configurations.
Clinical Evidence
Bench testing only. Testing included range of motion (135°), constraint testing, contact area analysis (femorotibial and patellofemoral), locking mechanism strength (anteroposterior motion at 100N), and cyclic fatigue testing of the tibial baseplate (5 million cycles at 200N-2.0KN). Porous coating testing included static tensile strength (>5,000 psi) and shear strength (>20 MPa). No clinical data provided.
Indicated for skeletally mature patients requiring knee arthroplasty for pain relief or improved function due to rheumatoid arthritis, osteoarthritis, traumatic arthritis, polyarthritis, collagen disorders, avascular necrosis, pseudogout, or posttraumatic joint loss (including patellofemoral erosion/dysfunction or prior patellectomy) and moderate valgus, varus, or flexion deformities. Also indicated for salvage of failed surgical attempts if knee can be balanced/stabilized. Cemented use only.
Regulatory Classification
Identification
A knee joint patellofemorotibial polymer/metal/polymer semi-constrained cemented prosthesis is a device intended to be implanted to replace a knee joint. The device limits translation and rotation in one or more planes via the geometry of its articulating surfaces. It has no linkage across-the-joint. This generic type of device includes prostheses that have a femoral component made of alloys, such as cobalt-chromium-molybdenum, and a tibial component or components and a retropatellar resurfacing component made of ultra-high molecular weight polyethylene. This generic type of device is limited to those prostheses intended for use with bone cement (§ 888.3027).
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2006 MAR I
U2 Total Knee System
Summary
# 510(k) Summary of Safety and Effectiveness
United UKNEE® Total Knee System ( K021657 )
| Company: | United Orthopedic Corporation |
|----------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------|
| Address: | No 57, Park Ave. 2, Science Park, Hsinchu 300, Taiwan |
| Phone Number: | +886-3-5773351 |
| Fax Number: | +886-3-5777156 |
| Date Prepared: | May 12, 2005 |
| Device Name: | U2 Total Knee System |
| Common Name: | Semi-constrained total knee prostheses |
| Classification Name: | Knee joint patellofemorotibial polymer/metal/polymer<br>semi-constrained cemented prosthesis per 21CFR 888.3560<br>This falls under the Orthopedics panel/87 |
Predicate Device:
The data that United Orthopedic Corporation included in this submission show the U2 Total Knee System (Cruciate retaining type and posterior stabilized type) is safe and effective. The U2 Total Knee System comprises a femoral component, which articulates with a polyethylene insert The underside of the insert component is flat and is snapped into the metal tibial component. The modular (snap-fit) locking mechanism of the insert components has proven to be component. safe and effective in the clinical area. The design and sizing of the femoral component correspond to the natural femoral anatomy, enhancing stress distribution and contributing to restore original femoral dimensions and normal rotation, extension and flexion. Each size of femur has the same intercondylar distance and radius of curvature; this feature is replicated on the insert component, thus allowing any size of femur to be matched with any size of tibial component. The dome shape all UHMWPE patellar design provides excellent contact and even distribution of stresses, simplifies implantation by eliminating need for rotational orientation. Test data indicate the U2 Total Knee System performs as well or better than the predicate device in all areas tested. Materials used in the manufacture of the U2 Total Knee System meet the property requirements of the ASTM standards associated with each material.
United Orthopedic Corporation, Taiwan.
Page: 1 / III
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#### (S) U2 Total Knee System
Summary
### Device Description:
U2 Total Knee system is the fixed bearing type with cruciate retaining and posterior stabilized It is a Patellofemorotibia, polymer/metal/polymer, semi-constrained, cemented knee design. prosthesis, which has a cobalt-chromium-molybdenum (Co-Cr-Mo) alloy femoral component and Ti alloy tibial component composed of a insert, machined from compressed molded The tibial baseplate UHMWPE flat, mechanical locked with metallic tibial baseplate. component is made of Ti-6A1-4V alloy which has groove for cement fixation. The cruciate retaining type of femoral component has w/ and w/o beaded porous coating design, and the posterior stabilized type has only w/o. The porous coating with two layers of beads has an about 55% of porosity, a 440 um of average pore size, and its thickness is 1.0 +0/+0.3 mm. The patella is machined from extruded UHMWPE bar. This device have 3 pegs and cement groove designed for cemented use only.
## Intended Use:
This device is indicated in knee arthroplasty for reduction or relief of pain and/or improved knee function in skeletally mature patients with severe knee pain and disability due to rheumatoid arthritis, osteoarthritis, primary and secondary traumatic arthritis, polyarthritis, collagen disorders, avascular necrosis of the femoral condyle or pseudogout, posttraumatic loss of joint configuration, particularly when there is patellofemoral erosion, dysfunction or prior patellectomy, moderate valgus, varus, or flexion deformities. This device may also be indicated in the salvage of previously failed surgical attempts if the knee can be satisfactorily balanced and stabilized at the time of surgery. This device system is designed for cemented use only.
### Basis for Substantial Equivalence:
Features comparable to predicate devices, United UKNEE® Total Knee System ( K021657 ) , include femoral components, patellar components, tibial trays and tibial inserts. The femoral components are available in cruciate retaining and posterior stabilized designs. Tibial inserts are available in a range of thickness and in cruciate retained and posterior stabilized designs. The patellar components are available in all plastic on-set designs with dome shape configurations.
United Orthopedic Corporation, Taiwan.
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#### Summary
# Test Results:
The U2 Total Knee System was analyzed following draft guidance for ccmented. semi-constrained total knee prostheses. The range of motion for the U2 Total Kncc System is 135°, satisfying necessary needs of daily life and general activities which exclude placing the patient in condition of severe loading caused higher risk for failure of the knee replacement. such as obesity, heavy labor, active sports participation, high levels of patient activity. likelihood of falls, alcohol or drug addiction and other disabilities, as appropriate.
Constraint testing compares with the UKNEE® Total Knee System and showed the U2 Total Knee System to be slightly more constraint.
Contact area between the femorotibial joint and patellofemoral joint is conducted respectively, and compared with other two products, AMK® and UKNEE®. From the data, we can find U2 Total Knee System could provide similar or greater contact area than others.
Comparing the tibial insert and tibial tray locking with UKNEE®, the average anteroposterior motion at 100N load of U2 Total Knee System is less than the predicated device, which means the locking mechanism of U2 Total Knee System is stronger than UKNEE®.
Cyclic test is performed on U2 system to evaluate the fatigue properties of tibial baseplate. Compressive cyclic load between 200N and 2.0KN, 5 million cycles is applied to the test system. There is no fracture on the tibial baseplate.
The static tensile strength of the beaded porous coating was conformed to endure 5,000 psi min. The shear strength of the beaded porous coating was more than 20 MPa. The porous coating has volume porosity between 30 and 70 percent, an average pore size between 100 and 1000 microns and a porous coating thickness between 1,000 and 1,300 microns.
Based on previous test results, the U2 Total Knee System is substantial equivalent :o UKNEE® Total Knee System.
nited Orthopedic Corporation, Taiwan.
Page: III / III
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Image /page/3/Picture/1 description: The image shows the logo for the U.S. Department of Health and Human Services. The logo consists of a circular seal with the text "DEPARTMENT OF HEALTH AND HUMAN SERVICES, USA" around the perimeter. Inside the circle is a stylized image of three human profiles facing to the right, with three curved lines above them.
Public Health Service
Food and Drug Administration 9200 Corporate Boulevard Rockville MD 20850
MAR I 2006
Mr. Gene Huang Regulatory Affairs Coordinator United Orthopedic Corporation No. 57, Park Ave. 2, Science Park Hsinchu 300, Taiwan
Re: K051640
Trade/Device Name: U2 Total Knee System Regulation Number: 21 CFR 888.3560 Regulation Name: Knee joint patellofemorotibial polymer/metal/polymer semiconstrained cemented prosthesis Regulatory Class: II Product Codes: JWH Dated: February 24, 2006 Received: February 27, 2006
Dear Mr. Huang:
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 (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. 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.
If your device is classified (see above) into either class II (Special Controls) or class III (PMA), it may be subject to such 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.
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
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Page 2 - Mr. Gene Huang
CFR Part 807); labeling (21 CFR Part 801); good manufacturing practice requirements as set forth in the quality systems (OS) regulation (21 CFR Part 820); and if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR 1000-1050. This letter will allow you to begin marketing your device as described in your Section 510(k) premarket notification. The FDA finding of substantial equivalence of your device to a legally marketed predicate device results in a classification 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), please contact the Office of Compliance at (240) 276-0120. Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21CFR Part 807.97). You may obtain other general information on your responsibilities under the Act from the Division of Small Manufacturers, International 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/industry/support/index.html.
Sincerely yours.
Heilut Lemmer us
Image /page/4/Picture/5 description: The image shows a handwritten word that appears to be "for". The word is written in a cursive style, with the letters connected. The "f" has a loop extending above the main body of the letter, and the "o" and "r" are joined together in a flowing manner. The writing is simple and clear, making the word easily readable.
Mark N. Melkerson, M.S. Acting Director Division of General, Restorative and Neurological Devices Office of Device Evaluation Center for Devices and Radiological Health
Enclosure
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| 510 (k) Number (if known): | K051640 |
|----------------------------|---------|
|----------------------------|---------|
Device Name: __U2 Total Knee System
# Indications for Use:
This device is indicated in knee arthroplasty for reduction or relief of pain and/or improved knee function in skeletally mature patients with severe knee pain and disability due to rheumatoid arthritis, osteoarthritis, primary and secondary traumatic arthritis, polyarthritis, collagen disorders, avascular necrosis of the femoral condyle or pseudogout, posttraumatic loss of joint configuration, particularly when there is patellofemoral erosion, dysfunction or prior patellectomy, moderate valgus, varus, or flexion deformities. This device may also be indicated in the salvage of previously failed surgical attempts if the knee can be satisfactorily balanced and stabilized at the time of surgery.
This device system is designed for cemented use only.
Prescription Use (Part 21 CFR 801 Subpart D)
AND/OR
Over-The-Counter Use (21 CFR 801 Subpart C)
1. 1. 1. 1. 1. 2. 2. 2. 2. 2. 2. 2. 2. 2. 2. 2. 2. 2. 2. 2. 2.
# (PLEASE DO NOT WRITE BELOW THIS LINE-CONTINUE ON ANOTHER PAGE OF
NEEDED)
510(k) Number.
Two short videos show you everything — or skip straight to the written tutorial if you'd rather read. You can reopen this any time from the Tutorial button in the top bar.
Part 1 — Search, results, and everyday workflows 16 min
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.
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
Click a device name to open its detail page: device facts on the left, a chat window on the right. Ask something like "Describe the training data". The answer carries little citation bubbles — click one to jump to the highlighted passage in the source PDF, so you can verify every AI answer against the document. There's also a Download PDF button for sharing.
How do you verify an AI chat answer on the device detail page?
Click the citation bubbles to jump to the relevant highlight in the source document.
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.
6. Collections
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.
How do you save a set of selected devices for later use?
Select the rows, go to the Collections tab, and create a labeled collection (e.g., "Cobb Angle Project"). You can reload the selection anytime and carry it into the PDF viewer and other tabs that support selections.
7. Product codes and the regulations tree
Click a product code in the results to jump to it in the regulations tree — identification text, sibling product codes, and devices you can open in a PDF viewer on the right. Click a regulation number to see its identification, special controls, and related product codes. You can also search by product code or regulation number at the top of the tree. Always read the special controls if any exist for your device — it broadens your search and sharpens pre-kickoff research.
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.
8. Chart view
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.
