510(k) · Cleared
Recalled · Class II · 2014Natural-Knee II Unicompartmentalknee System
Data to Oct 25, 2026 (FDA decisions) Oct 12, 2026 (recalls) Sep 30, 2026 (MAUDE) refreshed weekly
Intermedics Orthopedics · HRY Prosthesis, Knee, Femorotibial, Semi-Constrained, Cemented, Metal/Polymer
Cleared on Mar 8, 1996 after a 79-day review. The FDA summary names its predicate without a number. 22 later devices descend from it. It has been recalled once.
- Decided
- Mar 8, 1996
- Review
- 79 days
- Class
- Class II
- Product code
- HRY
- Recalls
- 1
- Predicates
- 0
22 later devices descend from it, 2 citing it directly.
- This deviceK955778 Natural-Knee II Unicompartmentalknee SystemIntermedics Orthopedics · 1996
- Descendant · cites it directly · 20 of its ownK033810 Natural-Knee II Unicompartmental Knee SystemCenterpulse Orthopedics, Inc. · 2004 · Recalled
- Descendant · 2 generations on · 19 of its ownK133811 Restoris Porous Partial Knee SystemMako Surgical Corp. · 2014
- Descendant · 3 generations on · 8 of its ownK163700 Bodycad Unicompartmental Knee SystemBodycad Laboratories, Inc. · 2017
- Descendant · 4 generations on · 7 of its ownK181302 Bodycad Unicompartmental Knee SystemBodycad Laboratories, Inc. · 2019
- Descendant · 3 generations on · 5 of its ownK190439 Engage™ Partial Knee SystemEngage Uni, LLC · 2019 · Recalled
Showing 5 of 22 descendants. See all descendants
Descendants cleared per year
Most influential descendants
Showing 5 of 22 · See all- K033810Natural-Knee II Unicompartmental Knee SystemCenterpulse Orthopedics, Inc. · 2004 · cites it directly20descendants
- K133811Restoris Porous Partial Knee SystemMako Surgical Corp. · 2014 · 2 generations on19descendants
- K163700Bodycad Unicompartmental Knee SystemBodycad Laboratories, Inc. · 2017 · 3 generations on8descendants
- K181302Bodycad Unicompartmental Knee SystemBodycad Laboratories, Inc. · 2019 · 4 generations on7descendants
- K190439Engage™ Partial Knee SystemEngage Uni, LLC · 2019 · 3 generations on5descendants
View FIG. 1 as a table
Line of descent and top descendants
| Generation | Number | Device | Applicant | Decided | Recalls |
|---|---|---|---|---|---|
| 0 (this device) | K955778 | Natural-Knee II Unicompartmentalknee System | Intermedics Orthopedics | 1996 | — |
| +1 | K033810 | Natural-Knee II Unicompartmental Knee System | Centerpulse Orthopedics, Inc. | 2004 | 1 |
| +2 | K133811 | Restoris Porous Partial Knee System | Mako Surgical Corp. | 2014 | — |
| +3 | K163700 | Bodycad Unicompartmental Knee System | Bodycad Laboratories, Inc. | 2017 | — |
| +4 | K181302 | Bodycad Unicompartmental Knee System | Bodycad Laboratories, Inc. | 2019 | — |
| +3 | K190439 | Engage™ Partial Knee System | Engage Uni, LLC | 2019 | 4 |
Descendants by year cleared
| Year cleared | Devices | With a Class I recall |
|---|---|---|
| 2002 | 1 | 0 |
| 2004 | 1 | 0 |
| 2014 | 1 | 0 |
| 2015 | 1 | 0 |
| 2017 | 1 | 0 |
| 2019 | 5 | 0 |
| 2021 | 4 | 0 |
| 2022 | 1 | 0 |
| 2023 | 1 | 0 |
| 2024 | 3 | 0 |
| 2025 | 1 | 0 |
| 2026 | 2 | 0 |
Sources: FDA 510(k) database (decision fields), the FDA summary (predicates and indications), FDA recall and enforcement reports, and MAUDE; processed by 510(k) Report. Verify on FDA.gov · Methodology and accuracy.
Planning a device in HRY? A 510(k) Report weighs predicate choices, recall history and review times for a new device like this one.
Top candidate predicates for a new HRY device
- #1 K193549 SIGMA High Performance (HP) Partial Knee Systemscore 0.4 · 5 generations · no Class I recall
What was it cleared against? (8)
Devices the submitter claimed this one is substantially equivalent to (*), and reference devices cited for a specific test or feature (†), as written in the FDA summary.
| Type | Number | Device | Decided |
|---|---|---|---|
| * | — | Howmedica PCA Unicompartmental Knee System Named without a submission number | |
| * | — | DePuy Synatomic Unicondylar Knee Named without a submission number | |
| * | — | Wright Medical Whiteside Ortholoc II Unicondylar Knee System Named without a submission number | |
| * | — | Osteonics Omnifit SCR Knee System Named without a submission number | |
| * | — | Zimmer Miller/Galante Unicompartmental Knee System Named without a submission number | |
| * | — | Kirschner Performance Unicompartmental Knee Named without a submission number | |
| * | — | Smith & Nephew Richards Genesis Unicompartmental Knee Named without a submission number | |
| * | — | Johnson & Johnson PFC Unicompartmental Knee System Named without a submission number |
What descends from it? (22)
See all 222 later devices cite it directly; ranked here by how many devices descend from each in turn.
Has anything in its family been recalled? (0 Class I)
Recalls of this device
| Date | Class | Recall | Root cause | Reason |
|---|---|---|---|---|
| Feb 25, 2014 | Class II | Z-1251-2014 | Storage | A complaint was received for a discolored All Poly Tibia. Root cause analysis found that the discoloration was the result of free radical oxidation. The oxidation process was advanced prematurely as a result of the machined component… |
No ancestor or descendant has a Class I recall.
What does this lineage say?
- Of its descendants, K033810 (Centerpulse Orthopedics, Inc., 2004) has gone furthest, with 20 descendants of its own.
How does its category compare?
All HRY devicesHRY Prosthesis, Knee, Femorotibial, Semi-Constrained, Cemented, Metal/Polymer: FDA decisions, review times, recalls and adverse event reports over 20 years.
FDA decisions per year · HRY
1in 2020
2026 to Oct 25, outlined.
Median 510(k) review, days · HRY
138in 2008
Receipt to decision; years with fewer than 3 clearances left blank.
Recalls per year · HRY
3in 2022
Class I (0 since 2007) Class II/III not classified
Adverse event reports per year · HRY
290in 2025
MAUDE reports naming product code HRY, not matched to any one device; reports are not rates.
View these four charts as a table
| Year | Decisions | Median 510(k) review, days | Recalls (Class I) | MAUDE reports |
|---|---|---|---|---|
| 2007 | 3 | 92 | 1 | 263 |
| 2008 | 3 | 138 | 1 | 285 |
| 2009 | 0 | — | 0 | 249 |
| 2010 | 1 | — | 0 | 180 |
| 2011 | 1 | — | 1 | 155 |
| 2012 | 1 | — | 0 | 137 |
| 2013 | 1 | — | 1 | 383 |
| 2014 | 1 | — | 0 | 305 |
| 2015 | 1 | — | 0 | 345 |
| 2016 | 1 | — | 1 | 343 |
| 2017 | 0 | — | 0 | 402 |
| 2018 | 0 | — | 0 | 613 |
| 2019 | 1 | — | 0 | 367 |
| 2020 | 1 | — | 1 | 1,054 |
| 2021 | 0 | — | 1 | 1,218 |
| 2022 | 0 | — | 3 | 840 |
| 2023 | 0 | — | 0 | 396 |
| 2024 | 0 | — | 0 | 430 |
| 2025 | 0 | — | 0 | 290 |
| 2026 | 0 | — | 0 | — |
What is it indicated for?
The Natural-Knee II - Unicompartmental Knee Prosthesis is intended for resurfacing of one side of the knee joint.
Indications for use read by OCR from a scanned FDA summary, so letters may be misread. Check the PDF before quoting it.
https://510kreport.com/device/K955778 · printed Nov 5, 2026
Cite this page
510(k) Report. “K955778: Natural-Knee II Unicompartmentalknee System.” Lineage record from FDA 510(k) data and the FDA summary. Updated Nov 3, 2026. Accessed Nov 5, 2026. https://510kreport.com/device/K955778
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Record history
- FDA decision record loaded May 2, 2026
- Summary read Oct 13, 2026 (extraction version 9eaa42aa01ed)
- Lineage and recalls computed Nov 3, 2026
- Page last updated Nov 3, 2026