K013340 · Plus Orthopedics · KRO · Dec 20, 2001 · Orthopedic
Device Facts
Record ID
K013340
Device Name
RT-PLUS KNEE ADDITIONAL COMPONENTS
Applicant
Plus Orthopedics
Product Code
KRO · Orthopedic
Decision Date
Dec 20, 2001
Decision
SESE
Submission Type
Special
Regulation
21 CFR 888.3510
Device Class
Class 2
Attributes
Therapeutic
Indications for Use
The RT-PLUS™ Knee System is a tri-compartmental rotating hinged prosthesis of the total condylar type. The system consists of femoral, tibial and patellar components. It is indicated for use as a replacement of the knee joint in which significant bone loss and/or ligamentous deficiencies have occurred due to tumors, trauma, infection, revision or connective tissue disorders. The RT-PLUS™ Modular Cemented Knee provides joint stability when any or all of the following structures are non-functional: MCL, LCL, PCL, ACL and the iliotibial band.
Device Story
RT-PLUS Knee System is a tri-compartmental rotating hinged total condylar knee prosthesis; consists of femoral, tibial, and patellar components. Device provides joint stability for patients with non-functional MCL, LCL, PCL, ACL, or iliotibial band. Modification adds size 2 and 10 components to existing size 4, 6, and 8 range. Implanted by orthopedic surgeons in clinical settings to replace knee joints compromised by trauma, tumors, infection, or revision. Output is a physical prosthetic joint replacement; restores mechanical stability and function to the knee. Benefits include joint stabilization and mobility restoration for patients with severe ligamentous or bone loss.
Clinical Evidence
Bench testing only. Biomechanical fatigue tests performed on the worst-case model; results favorable compared to predicate device and sufficient for in vivo loading.
Technological Characteristics
Tri-compartmental rotating hinged knee prosthesis; metal/polymer construction; cemented fixation. System includes femoral, tibial, and patellar components. Design is identical to predicate with expanded size range (sizes 2, 4, 6, 8, 10).
Indications for Use
Indicated for knee joint replacement in patients with significant bone loss or ligamentous deficiencies due to tumors, trauma, infection, revision, or connective tissue disorders. Contraindicated in patients with acute/chronic local or systemic infections, serious muscle/nerve/blood vessel lesions, bony defects/poor bone quality endangering stability, or concurrent diseases interfering with implant function.
Regulatory Classification
Identification
A knee joint femorotibial metal/polymer constrained cemented prosthesis is a device intended to be implanted to replace part of a knee joint. The device limits translation or rotation in one or more planes and has components that are linked together or affined. This generic type of device includes prostheses composed of a ball-and-socket joint located between a stemmed femoral and a stemmed tibial component and a runner and track joint between each pair of femoral and tibial condyles. The ball-and-socket joint is composed of a ball at the head of a column rising from the stemmed tibial component. The ball, the column, the tibial plateau, and the stem for fixation of the tibial component are made of an alloy, such as cobalt-chromium-molybdenum. The ball of the tibial component is held within the socket of the femoral component by the femoral component's flat outer surface. The flat outer surface of the tibial component abuts both a reciprocal flat surface within the cavity of the femoral component and flanges on the femoral component designed to prevent distal displacement. The stem of the femoral component is made of an alloy, such as cobalt-chromium-molybdenum, but the socket of the component is made of ultra-high molecular weight polyethylene. The femoral component has metallic runners which align with the ultra-high molecular weight polyethylene tracks that press-fit into the metallic tibial component. The generic class also includes devices whose upper and lower components are linked with a solid bolt passing through a journal bearing of greater radius, permitting some rotation in the transverse plane, a minimal arc of abduction/adduction. This generic type of device is limited to those prostheses intended for use with bone cement (§ 888.3027).
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SPECIAL 510(K) DEVICE MODIFICATION RT-PLUS Knee Additional Components October 5, 2001
DEC 2 0 2001
KD13340
## 510(k) Summary of Safety and Effectiveness 510(k) Summary of Safety and Effectiveness
[in accordance with SMDA of 1990, 21 CFR 807.92(c)]
- PLUS ORTHOPEDICS Contact: 6055 Lusk Blvd. San Diego, CA 92121 Tel: 858-550-3800 x 2506 Attn: Mr. Hartmut Loch, RAC Director, Regulatory Affairs
- RT-PLUS™ Knee System Trade name:
Hinged Knee Prosthesis Common name:
Prosthesis Knee, Femorotibial, Constrained, Cemented, Metal/Polymer Classification & 888.3510 - Class II name: Product Code: KRO - 87 Orthopedic Device Panel
RT-PLUS Knee System, S/E May 11, 2001 - K003504 manufactured by Predicate Device: PLUS Endoprothetik AG, Switzerland
The RT-PLUS™ Additional Knee Components are identical to the Device predicate device, except sizes 2 and 10 were added to the existing sizes Modification 4, 6, and 8 of the RT-PLUS™ Knee System. Description:
## The RT-PLUS™ Knee System is a tri-compartmental rotating hinged Indications: prosthesis of the total condylar type. The system consists of femoral, tibial and patellar components. It is indicated for use as a replacement of the knee joint in which significant bone loss and/or ligamentous deficiencies have occurred due to tumors, trauma, infection, revision or connective tissue disorders. The RT-PLUS™ Modular Cemented Knee provides joint stability when any or all of the following structures are nonfunctional: MCL, LCL, PCL, ACL and the iliotibial band.
Contraindications include acute or chronic infections (local or systemic), Contraindications: serious lesions of muscles, nerves or blood vessels, which put the affected limb at risk, bony defects or poor bone quality, which might endanger the stability of the prosthesis, and any concurrent disease, which might interfere with the function of the implant.
Biomechanical fatigue tests have been performed on the worst-case Performance model. The test results of the additional components were favorable to data: the predicate device and are sufficient for in vivo loading.
15
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Image /page/1/Picture/12 description: The image is a black and white logo for the U.S. Department of Health and Human Services. The logo features a circular border with the text "DEPARTMENT OF HEALTH & HUMAN SERVICES • USA" around the edge. Inside the circle is a stylized image of three overlapping, curved shapes that resemble a bird in flight.
Food and Drug Administration 9200 Corporate Boulevard Rockville MD 20850
Mr. Hartmut Loch, RAC Director, Regulatory Affairs PLUS Orthopedics 6055 Lusk Boulevard San Diego, CA 92121-2700
DEC 2 0 2001
Re: K013340
Trade/Device Name: RT-PLUS" Hinged Knee Regulation Number: 21 CFR §888.3510 Regulation Name: Knee joint femorotibial metal/polymer constrained cemented prosthesis Regulatory Class: Class II Product Code: KRO Dated: November 16, 2001 Received: November 20, 2001
Dear Mr. Loch:
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 with the providions of the approval application (PMA). You may, therefore, market the approval or a promance apple on and provisions of the Act. The general controls provisions of the Act include requirements for annual registration, listing of devices, provisions facturing 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 (I writ), it may be bactor be found in the Code of Federal Regulations, Title 21, Parts arround your 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 r lease on 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 I coderal agencies: "Foundsiveing (21 CFR Part 807); labeling (21 CFR Part 801); good manufacturing practice requirements as set forth in the quality systems (QS) regulation (21 CFR Part 820); and if applicable, the electronic product radiation control provisions
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Page 2 – Mr. Hartmut Loch
This letter will allow you to begin marketing your device as described in your Section 510(k) I his letter will anow you to ocgin maxioning your antial equivalence of your device to a legally premarket notification. The IDA inding of subscribed on of a market of your device to proceed to the market.
If you desire specific advice for your device on our labeling regulation (21 CFR Part 801 and if you desire specific advice for your dovice diagnostic devices), please contact the Office of additionally 21 CFC Part 807.10 for mi 120 c.m. 1120 c.m. 112 promotion and advertising of Compliance at (301) 394-6057. Tidnitionship to questions of (301) 594-4639. Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21CFR Part 807.97). Other general information on your responsibilities under the Act may be obtained from the Division (800) Other general information on your respend and Consumer Assistance at its toll-free number (800) 638-2041 or (301) 443-6597 or at its Internet address 036-2011 or (9) fda gov/cdrh/dsma/dsmamain.html
Sincerely yours,
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
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SPECIAL 510(K) DEVICE MODIFICATION RT-PLUS Knee Additional Components October 5, 2001
Page 1
510(k) Number:
Device Name(s):
RT-PLUS Knee Additional Components
Indications for Use:
The RT-PLUS™ Knee System is a tri-compartmental rotating hinged prosthesis of the total condylar type. The system consists of femoral, tibial and patellar components. It is indicated for use as a replacement of the knee joint in which significant bone loss and/or ligamentous deficiencies have occurred due to tumors, trauma, infection, revision or connective tissue disorders. The RT-PLUS™ Modular Cemented Knee provides joint stability when any or all of the following structures are non-functional: MCL, LCL, PCL, ACL and the iliotibial band.
PLEASE DO NOT WRITE BELOW THIS LINE - CONTINUE ON ANOTHER PAGE IF NECESSARY
Concurrence of CDRH, Office of Device Evaluation (ODE)
| (Division Sign-Off) |
|-----------------------------------------------------------|
| Division of General, Restorative and Neurological Devices |
| 510(k) Number | K013340 |
|---------------|---------|
|---------------|---------|
| Prescription Use | X | OR | Over-The-Counter-Use |
|----------------------|---|----|--------------------------|
| (Per 21 CFR 801.109) | | | (Optional format 1-2-96) |
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.
