K082424 · United Orthopedic Corp. · JWH · Dec 16, 2008 · Orthopedic
Device Facts
Record ID
K082424
Device Name
UNITED U2 TOTAL KNEE SYSTEM
Applicant
United Orthopedic Corp.
Product Code
JWH · Orthopedic
Decision Date
Dec 16, 2008
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 contraction. This device is intended for use in patients who require augmentation and/or stem extensions due to inadequate bone stock and/or require constrained stabilization for tibiofemoral joint due to soft tissue imbalance.
Device Story
U2 Total Knee System - PSA Type is a semi-constrained, cemented knee prosthesis for primary or revision arthroplasty. System includes Co-Cr-Mo femoral component, UHMWPE tibial insert, and Ti-6Al-4V tibial baseplate. Modular components include femoral/tibial augments, stem extensions, and offset stem adapters to address bone stock deficiency and soft tissue imbalance. Device implanted by orthopedic surgeons in clinical settings. Modular snap-fit locking mechanism secures insert to baseplate. Provides tibiofemoral stability and joint function restoration. Benefits include improved joint configuration and pain relief for patients with severe knee pathology.
Clinical Evidence
Bench testing only. Tests included tibiofemoral range of motion, finite element analysis of tibial tray, joint constraints, contact area/pressure, surface finish, locking strength, and fatigue testing for metal baseplate and insert spine.
Indicated for skeletally mature patients requiring knee arthroplasty for pain relief/function improvement due to rheumatoid arthritis, osteoarthritis, traumatic arthritis, polyarthritis, collagen disorders, avascular necrosis, or posttraumatic joint loss. Includes patients needing augmentation/stem extensions for inadequate bone stock or constrained stabilization for soft tissue imbalance (valgus, varus, flexion contraction).
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).
ZIMMER NexGen Complete Knee Solution Legacy CCK Type (K960279)
Submission Summary (Full Text)
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DEC 1 6 2008
KOrzuzu
ਹੈ U2 Total Knee System - PSA Type
510(k) Summary
## 510(k) Summary of Safety and Effectiveness
| Company: | United Orthopedic Corporation |
|----------------|------------------------------------------------------|
| Address: | No 57, Park Ave 2, Science Park, Hsinchu 300, Taiwan |
| Phone Number: | +886-3-5773351 ext. 331 |
| Fax Number: | +886-3-5670452 |
| Date Prepared: | August 07, 2008 |
| Device Name: | U2 Total Knee System - PSA Type |
| Common Name: | Semi-constrained total knee prostheses |
Classification Name:
Predicate Device:
1. "UNITED" U2 Total Knee system (K051640)
This falls under the Orthopedics panel.
Knee joint patellofemorotibial polymer/metal/polymer
semi-constrained cemented prosthesis per 21CFR 888.3560.
2. "ZIMMER" NexGen Complete Knee Solution Legacy CCK Type (K960279)
U2 Total Knee System - Posterior Stabilized Augmentable (PSA) Type is intended for use in patients who require augmentation and/or stem extensions due to inadequate bone stock and/or require constrained stabilization for tibiofemoral joint due to soft tissue imbalance. The U2 Total Knee System - PSA Type comprises a femoral component, which articulates with an ultrahigh molecular weight polyethylene insert component. The undersurface of the insert component is flat and is snapped into the metal baseplate component. The modular (snap-fit) locking mechanism of the insert components has proven to be safe and effective in the clinical area. The U2 Total Knee System - PSA Type collocate with dome shape all UHMWPE patellar (K051640), which provides excellent contact and even distribution of stresses, simplifies implantation by eliminating need for rotational orientation. The U2
UOC-FDA-009
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#### D U2 Total Knee System - PSA Type
510(k) Summary
Total Knee System - PSA Type also includes femoral augment set, tibial augment, stem component, offset stem adapter, and femoral screw. These assembled components are designed for use to advance the stability of knee joint or the option for surgeon in both difficult primary and revision surgeries. Test data indicate the U2 Total Knee System - PSA Type performs as well or better than the predicate devices in all areas tested. Materials used in the manufacture of the U2 Total Knee System - PSA Type meet the property requirements of the ASTM standards associated with each material.
#### Device Description:
"UNITED" U2 Total Knee System - Posterior Stabilized Augmentable (PSA) type is an extended design of "UNITED" U2 Total Knee system. It is a Patellofemorotibia, polymer/metal/polymer, semi-constrained, cemented knee prosthesis, which has a cobalt-chromium-molybenum (Co-Cr-Mo) alloy femoral component and a tibial component composed of a polyethylene insert machined from compressed molded UHMWPE and a Ti-6Al-4V metallic tibial baseplate. This system is intended for use in patients who require augmentation and/or stem extensions due to inadequate bone stock. There are a variety of components including femoral augment set, tibial augment, stem extension and offset stem adapter that provides more choices for surgeon to treat their patients. In addition, this system also provides more constraint of tibiofemoral joint when patients require more constrained stabilization due to inadequate mediolateral. anterioposterior or varus-valgus soft tissue imbalance. The components of U2 Total Knee system-PSA Type are listed as below.
"UNITED" U2 Total Knee System - PSA Type
A Femoral component, PSA type
- A Tibial insert, PSA type
- Tibial baseplate
Tibial baseplate, PSA type, screw locking
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- Tibial baseplate, PSA type -
- A Femoral augment set
- Femoral augment, Posterior -
- Femoral augment, Distal
- > Tibial augment
- Tibial augment, screw locking -
- -Tibial augment
#### > Stem component
- Straight stem, PSA type -
- Curved stem, PSA type .
- Straight stem, PSA type, cemented -
- Curved stem, PSA type, cemented .
- Offset stem adapter A
- > Femoral screw
#### 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 contraction. This device is intended for use in patients who require augmentation and/or stem extensions due to inadequate bone stock and/or require constrained stabilization for tibiofemoral joint due to soft tissue imbalance.
### Basis for Substantial Equivalence:
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#### Basis for Substantial Equivalence:
The safety and effectiveness of U2 Total Knee system - PSA Type are substantial equivalence to the "UNITED" U2 Total Knee System - PS Type which was previously cleared by FDA (K051640). In addition, U2 Total Knee system - PSA Type is also substantial equivalence to the "ZIMMER" NexGen Complete Knee Solution Legacy CCK Type (Zimmer - LCCK) which was previously cleared by FDA (K960279). Both these two devices were designed to provide more constrained of tibiofemoral joint.
#### Performance Test - Bench:
The following tests were performed:
- 1. Tibiofemoral Range of Motion
- 2. Finite Element Analysis of Tibial Tray
- 3. Constraints of the Tibiofemoral Joint
- 4. Contact Area and Contact Pressure in Tibiofemoral Joint
- 5. Articulating Surface Finish of Femoral Component and Tibial Insert
- 6. Locking Strength of Tibial Component
- 7. Fatigue Test for Metal Tibial Baseplate
- 8. Fatigue Test for Tibial Insert Spine
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#### DEPARTMENT OF HEALTH & HUMAN SERVICES
Image /page/4/Picture/1 description: The image shows the logo for the U.S. Department of Health & Human Services. The logo consists of a stylized eagle with three legs and a circular border. The text "DEPARTMENT OF HEALTH & HUMAN SERVICES - USA" is written around the border of the circle.
Food and Drug Administration 200 Corporate Boulevard Rockville MD 20850
United Orthopedic Corporation % Mr. Rudy Chen Regulatory Affairs No. 57, Park Avenue 2, Science Park, Hsinchu, 300 Taiwan
DEC 1 6 2008
Re: K082424
Trade/Device Name: U2 Total Knee System - PSA Type Regulation Number: 21 CFR 888.3560
Regulation Name: Knee joint patellofemorotibial polymer semi-constrained cemented prosthesis
Regulatory Class: II Product Codes: JWH Dated: December 12, 2008
Received: December 16, 2008
Dear Mr. Chen:
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 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.
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## Page 2 - Mr. Rudy Chen
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 Center for Devices and Radiological Health's (CDRH's) Office of Compliance at (240) 276-0120. Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21CFR Part 807.97). For questions regarding postmarket surveillance, please contact CDRH's Office of Surveillance and Biometric's (OSB's) Division of Postmarket Surveillance at 240-276-3474. For questions regarding the reporting of device adverse events (Medical Device Reporting (MDR)), please contact the Division of Surveillance Systems at 240-276-3464. 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 (240) 276-3150 or at its Internet address http://www.fda.gov/cdrh/industry/support/index.html.
Sincerely yours,
Mark M. Milliman
Mark N. Melkerson Director Division of General, Restorative and Neurological Devices Office of Device Evaluation Center for Devices and Radiological Health
Enclosure
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# Indication for Use
#### 510 (k) Number (if known): k082424
Device Name: U2 Total Knee System - PSA Type
## 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 patellectorny, moderate valgus, varus, or flexion contraction. This device is intended for use in patients who require augmentation and/or stem extensions due to inadequate bone stock and/or require constrained stabilization for tibiofemoral joint due to soft tissue imbalance
Prescription Use x (Part 21 CFR 801 Subpart D) AND/OR
Over-The-Counter Use (21 CFR 801 Subpart C)
(PLEASE DO NOT WRITE BELOW THIS LINE-CONTINUE ON ANOTHER PAGE IF NEEDED)
Concurrence of CDRH, Office of Device Evaluation (ODE)
(Division Sign-Off) Division of General, Restorative, and Neurological Devices
Page of
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.