K973087 · Sulzer Orthopedics, Inc. · LZO · Nov 14, 1997 · Orthopedic
Device Facts
Record ID
K973087
Device Name
MOST HEX INTRAMEDULLARY (I/M) STEM
Applicant
Sulzer Orthopedics, Inc.
Product Code
LZO · Orthopedic
Decision Date
Nov 14, 1997
Decision
SESE
Submission Type
Traditional
Regulation
21 CFR 888.3353
Device Class
Class 2
Attributes
Therapeutic
Indications for Use
The MOST System is intended to replace the proximal, distal and/or total femur, especially in cases that require extensive resection and restoration. The Hex I/M Stem is intended for cemented use only in these situations. Specific diagnostic indications for use of the MOST System include: - metastatic diseases (e.g., osteosarcomas, chondrosarcomas, giant cell tumors, bone tumors) requiring extensive resection(s) and replacement(s) of the proximal and/or distal femur; - patient conditions of noninflammatory degenerative joint disease (NIDJD), e.g., avascular necrosis, osteoarthritis, and inflammatory joint disease (IJD), e.g., rheumatoid arthritis, requiring extensive resection and replacement of the proximal and/or distal femur; - patients suffering from severe arthropathy of the hip and/or knee that does not respond to any conservative therapy or better alternative surgical treatment; - revision cases requiring extensive resection(s) and replacement(s) of the proximal, distal, or total femur.
Device Story
The MOST Hex I/M Stem is a modular orthopedic implant component designed for cemented fixation in the femoral canal. It serves as the stem portion for proximal, distal, or total femoral replacement in oncology or severe trauma cases. The device features a hexagonal shape to provide rotational stability and a taper for connection to other modular components. A CSTi coating on the neck facilitates tissue attachment. Used by orthopedic surgeons in clinical/surgical settings, the device replaces diseased or damaged bone, aiming to restore structural integrity and joint function. It is intended for cemented use only.
Clinical Evidence
No clinical data provided; bench testing only.
Technological Characteristics
Materials: CoCr alloy (ASTM F1537) with CSTi coating. Design: Hexagonal cross-section for rotational stability; modular taper connection. Fixation: Cemented only. Sterilization: Not specified.
Indications for Use
Indicated for patients requiring extensive resection and replacement of the proximal, distal, or total femur due to metastatic bone disease (e.g., osteosarcoma, chondrosarcoma, giant cell tumor), noninflammatory degenerative joint disease (e.g., avascular necrosis, osteoarthritis), inflammatory joint disease (e.g., rheumatoid arthritis), severe hip/knee arthropathy unresponsive to conservative therapy, or revision surgery.
Regulatory Classification
Identification
A hip joint metal/ceramic/polymer semi-constrained cemented or nonporous uncemented prosthesis is a device intended to be implanted to replace a hip joint. This device limits translation and rotation in one or more planes via the geometry of its articulating surfaces. It has no linkage across-the-joint. The two-part femoral component consists of a femoral stem made of alloys to be fixed in the intramedullary canal of the femur by impaction with or without use of bone cement. The proximal end of the femoral stem is tapered with a surface that ensures positive locking with the spherical ceramic (aluminium oxide, A12 03 ) head of the femoral component. The acetabular component is made of ultra-high molecular weight polyethylene or ultra-high molecular weight polyethylene reinforced with nonporous metal alloys, and used with or without bone cement.
Predicate Devices
Sulzer Orthopedics MOST System
Wright Medical Segmented Oncology System (S.O.S.)
Waldermar Link MP Reconstruction Prosthesis
Johnson & Johnson/Joint Medical Products Noiles Knee System
Howmedica Kinematic II Rotating Hinge Knee System
Submission Summary (Full Text)
{0}------------------------------------------------
August 13, 1997
NOV 1 4 1997
K973087
In accordance with the Food and Drug Administration Interim Rule to implement provisions of the Safe Medical Devices Act of 1990 and in conformance with 21 CFR 807, this is to serve as a 510(k) summary for the Sulzer Orthopedics Inc. MOST (Modular Options for Severe Bone Loss and Trauma) System Hex I/M Stem.
| Submitter: | Sulzer Orthopedics Inc.<br>9900 Spectrum Drive<br>Austin, TX 78717<br>(512)432-9900 |
|-------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| Contact Person: | Jacquelyn Hughes<br>Manager, Regulatory Affairs |
| Classification Name: | 21CFR 888.3353 - Hip joint metal/ceramic/polymer semi-<br>constrained cemented or nonporous uncemented prosthesis<br><br>21CFR 888.3510 - Knee joint femorotibial metal/polymer<br>constrained cemented prosthesis |
| Common/Usual Name: | Cemented stem for modular trauma or oncology applications |
| Trade/Proprietary Name: | MOST Hex Intramedullary (I/M) Stem |
#### PRODUCT DESCRIPTION:
The MOST System is used for the replacement of the proximal, distal and/or total femur. Unlike primary hip and knee systems, this system is used where the amount of femoral resection and restoration required is extreme (e.g., in oncology cases). A total replacement is possible in those cases where no part of the femur can be salvaged.
The Hex I/M stems are hex shaped and designed to serve as the modular stem portion of either the proximal or distal femoral replacement. A taper feature at the end of the stem allows for connection to the mating modular component. The hex shape allows for rotational stability within the femoral canal once the stem is cemented into place. A ring of CSTi coating around the neck of the CoCr stem (ASTM F1537) allows for tissue attachment.
{1}------------------------------------------------
### SPECIFIC DIAGNOSTIC INDICATIONS:
The MOST System is intended to replace the proximal, distal and/or total femur, especially in cases that require extensive resection and restoration. The Hex I/M Stem is intended for cemented use only in these situations. Specific diagnostic indications for use of the MOST System include:
- metastatic diseases (e.g., osteosarcomas, chondrosarcomas, giant cell tumors, bone tumors) . requiring extensive resection(s) and replacement(s) of the proximal and/or distal femur;
- patient conditions of noninflammatory degenerative joint disease (NIDJD), e.g., avascular . necrosis, osteoarthritis, and inflammatory joint disease (IJD), e.g., rheumatoid arthritis, requiring extensive resection and replacement of the proximal and/or distal femur;
- patients suffering from severe arthropathy of the hip and/or knee that does not respond to . any conservative therapy or better alternative surgical treatment;
- . revision cases requiring extensive resection(s) and replacement(s) of the proximal, distal, or total femur.
### SUBSTANTIAL EQUIVALENCE:
Substantial equivalence determination is based on comparison of the MOST Hex I/M Stem to the following legally marketed predicate competitive devices:
- 파 Sulzer Orthopedics MOST System
- 트 Wright Medical Segmented Oncology System (S.O.S.)
- 비 Waldermar Link MP Reconstruction Prosthesis
- 체 Johnson & Johnson/Joint Medical Products Noiles Knee System
- 동 Howmedica Kinematic II Rotating Hinge Knee System
{2}------------------------------------------------
Image /page/2/Picture/1 description: The image shows the logo for the U.S. Department of Health & Human Services. The logo consists of a stylized image of an eagle with its wings spread, facing to the right. The words "DEPARTMENT OF HEALTH & HUMAN SERVICES - USA" are arranged in a circular pattern around the eagle image.
Food and Drug Administration 9200 Corporate Boulevard Rockville MD 20850
Mitchell A. Dhority, RAC Senior Requlatory Affairs Specialist Sulzer Orthopedics, Inc. 9900 Spectrum Drive Austin, Texas 78717
NOV 1 4 1997
K973087 Re: MOST System Hex Intramedullary (I/M) Stem Trade Name: Requlatory Class: II Product Codes: JDI, LZO, and KRO Dated: August 14, 1997 Received: August 18, 1997
Dear Mr. Dhority:
We have reviewed your Section 510(k) notification of intent to market the device referenced above and we have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to 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). 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 (Premarket Approval), 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 895. ਸੇ substantially equivalent determination assumes compliance with the current Good Manufacturing Practice requirement, as set forth in the Quality System Requlation (QS) for Medical Devices: General regulation (21 CFR Part 820) and that, through periodic (QS) inspections, the Food and Drug Administration (FDA) will verify such assumptions. Failure to comply with the GMP requlation may result in requlatory action. In addition, FDA may publish further announcements concerning your device in the Federal Register. Please note: this response to your premarket notification submission does not affect any obligation you might have under sections 531 through 542 of the Act for devices under the Electronic Product Radiation Control provisions, or other Federal laws or requlations.
{3}------------------------------------------------
Page 2 - Mitchell A. Dhority, RAC
This letter will allow you to begin marketing your device as described in your 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 and additionally 809.10 for in vitro diagnostic devices), please contact the Office of Compliance at (301) 594-4659. Additionally, for questions on the promotion and advertising of your device, please contact the Office of Compliance at (301) 594-4639. Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR 807.97). Other general information on your responsibilities under the Act may be obtained from the Division of Small Manufacturers Assistance at its toll-free number (800) 638-2041 or (301) 443-6597 or at its internet address "http://www.fda.gov/cdrh/dsmamain.html".
Sincerely yours,
a M. Witten, Ph.D., M.D. Director Division of General and Restorative Devices Office of Device Evaluation Center for Devices and Radiological Health
Enclosure
{4}------------------------------------------------
# k973087
510(k) Number (if known):
Device Name: Modular Options for Severe Bone Loss or Trauma (MOST) - Hex I/M Stem
## Indications for Use:
The MOST System is intended to replace the proximal, distal and/or total femur, especially in cases that require extensive resection and restoration. The Hex I/M Stem is intended for cemented use only in these situations. Specific diagnostic indications for use of the MOST System include:
- metastatic diseases (e.g., osteosarcomas, chondrosarcomas, giant cell tumors, bose . tumors) requiring extensive resection(s) and replacement(s) of the proximal and/or distal femur;
- patient conditions of noninflammatory degenerative joint disease (NIDJD), e.g., . avascular necrosis, osteoarthritis, and inflammatory joint disease (IID), e.g., rheumatoid arthritis, requiring extensive resection and replacement of the proximal and/or distal femur;
- patients suffering from severe arthropathy of the hip and/or knee that does not respond . to any conservative therapy or better alternative surgical treatment;
- revision cases requiring extensive resection(s) and replacement(s) of the proximal, . distal, or total femur.
### (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 Devices | |
| 510(k) Number | K973087 |
| Prescription Use | X |
|----------------------|---|
| OR | |
| Over-the Counter Use | |
(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.
