510(k) · Cleared
Recalled · Class II · 2014Natural-Knee II Unicompartmental Knee System
Data to Oct 25, 2026 (FDA decisions) Oct 12, 2026 (recalls) Sep 30, 2026 (MAUDE) refreshed weekly
Centerpulse Orthopedics, Inc. · HRY Prosthesis, Knee, Femorotibial, Semi-Constrained, Cemented, Metal/Polymer
Cleared on Mar 5, 2004 as substantially equivalent to K955778 (Intermedics Orthopedics, 1996) and 5 other predicates after an 88-day review. Its family tree reaches back 2 generations to 1996. 20 later devices descend from it. It has been recalled once.
- Decided
- Mar 5, 2004
- Review
- 88 days
- Class
- Class II
- Product code
- HRY
- Recalls
- 1
- Predicates
- 6
Its longest line of descent runs back 2 generations to K954481 (1996). 7 ancestors in all, the oldest K883969 (1989). 20 later devices descend from it, 1 citing it directly.
- Root · 2 generations backK954481 P.F.C. Uni-Compartmental Knee SystemJohnson & Johnson Professionals, Inc. · 1996
- 1 generation backK982859 UC-Plus Solution Unicondylar Knee SystemPlus Orthopedics · 1999 · Recalled
- This deviceK033810 Natural-Knee II Unicompartmental Knee SystemCenterpulse Orthopedics, Inc. · 2004
- Descendant · cites it directly · 19 of its ownK133811 Restoris Porous Partial Knee SystemMako Surgical Corp. · 2014
- Descendant · 2 generations on · 8 of its ownK163700 Bodycad Unicompartmental Knee SystemBodycad Laboratories, Inc. · 2017
- Descendant · 3 generations on · 7 of its ownK181302 Bodycad Unicompartmental Knee SystemBodycad Laboratories, Inc. · 2019
- Descendant · 2 generations on · 5 of its ownK190439 Engage™ Partial Knee SystemEngage Uni, LLC · 2019 · Recalled
- Descendant · 3 generations on · 4 of its ownK191150 Bodycad Unicompartmental Knee SystemBodycad Laboratories, Inc. · 2019
Showing 5 of 20 descendants. See all descendants
Descendants cleared per year
Most influential descendants
Showing 5 of 20 · See all- K133811Restoris Porous Partial Knee SystemMako Surgical Corp. · 2014 · cites it directly19descendants
- K163700Bodycad Unicompartmental Knee SystemBodycad Laboratories, Inc. · 2017 · 2 generations on8descendants
- K181302Bodycad Unicompartmental Knee SystemBodycad Laboratories, Inc. · 2019 · 3 generations on7descendants
- K190439Engage™ Partial Knee SystemEngage Uni, LLC · 2019 · 2 generations on5descendants
- K191150Bodycad Unicompartmental Knee SystemBodycad Laboratories, Inc. · 2019 · 3 generations on4descendants
View FIG. 1 as a table
Line of descent and top descendants
| Generation | Number | Device | Applicant | Decided | Recalls |
|---|---|---|---|---|---|
| −2 | K954481 | P.F.C. Uni-Compartmental Knee System | Johnson & Johnson Professionals, Inc. | 1996 | — |
| −1 | K982859 | UC-Plus Solution Unicondylar Knee System | Plus Orthopedics | 1999 | 1 |
| 0 (this device) | K033810 | Natural-Knee II Unicompartmental Knee System | Centerpulse Orthopedics, Inc. | 2004 | — |
| +1 | K133811 | Restoris Porous Partial Knee System | Mako Surgical Corp. | 2014 | — |
| +2 | K163700 | Bodycad Unicompartmental Knee System | Bodycad Laboratories, Inc. | 2017 | — |
| +3 | K181302 | Bodycad Unicompartmental Knee System | Bodycad Laboratories, Inc. | 2019 | — |
| +2 | K190439 | Engage™ Partial Knee System | Engage Uni, LLC | 2019 | 4 |
| +3 | K191150 | Bodycad Unicompartmental Knee System | Bodycad Laboratories, Inc. | 2019 | — |
Other ancestors by year cleared
| Year cleared | Devices | With a Class I recall |
|---|---|---|
| 1989 | 1 | 0 |
| 1996 | 1 | 0 |
| 1997 | 1 | 0 |
| 2001 | 2 | 0 |
Descendants by year cleared
| Year cleared | Devices | With a Class I recall |
|---|---|---|
| 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? (6)
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 |
|---|---|---|---|
| * | K955778 | Natural-Knee II Unicompartmentalknee SystemSummary page 1…PREDICATE DEVICES: The predicate devices chosen to demonstrate substantial equivalence are: _ Natural-Knee II Unicompartmental Knee System (K955778) * Natural-Knee Unicompartmental Knee System (K883969) * Natural-Knee IITotal Knee System with CSTi (… | 1996 |
| * | K883969 | Uni-Knee Component of the Natural-Knee SystemSummary page 1…emonstrate substantial equivalence are: _ Natural-Knee II Unicompartmental Knee System (K955778) * Natural-Knee Unicompartmental Knee System (K883969) * Natural-Knee IITotal Knee System with CSTi (P940002) · Wright Medical ADVANCE® Unicompartmental Kn… | 1989 |
| * | P940002 | Natural-Knee (R) and Natural Knee (R)II W/Csti (TM)Summary page 1…II Unicompartmental Knee System (K955778) * Natural-Knee Unicompartmental Knee System (K883969) * Natural-Knee IITotal Knee System with CSTi (P940002) · Wright Medical ADVANCE® Unicompartmental Knee (K012591) * DePuy Preservation T M Unicompartmental… | 1997 |
| * | K012591 | Advance Unicondylar Knee SystemSummary page 1…nicompartmental Knee System (K883969) * Natural-Knee IITotal Knee System with CSTi (P940002) · Wright Medical ADVANCE® Unicompartmental Knee (K012591) * DePuy Preservation T M Unicompartmental Knee (K010810) · Plus Orthopedics UC Plus T M Unicompartme… | 2001 |
| * | K010810 | Depuy Preservation Unicondylar Knee ProsthesisSummary page 1…tal Knee System with CSTi (P940002) · Wright Medical ADVANCE® Unicompartmental Knee (K012591) * DePuy Preservation T M Unicompartmental Knee (K010810) · Plus Orthopedics UC Plus T M Unicompartmental Knee (K982859) DEVICE DESCRIPTION: The Natu… | 2001 |
| * | K982859 | UC-Plus Solution Unicondylar Knee SystemSummary page 1…nicompartmental Knee (K012591) * DePuy Preservation T M Unicompartmental Knee (K010810) · Plus Orthopedics UC Plus T M Unicompartmental Knee (K982859) DEVICE DESCRIPTION: The Natural-Knee II Unicompartmental Knee System is a conservative, cost-effective… | 1999 |
What descends from it? (20)
See all 201 later device cites it directly; ranked here by how many devices descend from each in turn.
| Number | Device | Decided | Descendants |
|---|---|---|---|
| K133811 | Restoris Porous Partial Knee System | 2014 | 19 |
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-1252-2014 | 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?
- The line of descent spans 8 years and passes through 3 companies; a new generation was cleared every 4.6 years on median.
- 3 of the 7 ancestors have a recall of any class.
- Of its descendants, K133811 (Mako Surgical Corp., 2014) has gone furthest, with 19 descendants of its own.
- 1 other device also cites its predicate K955778.
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 is intended for use in:
1. Unicompartmental noninflammatory degenerative joint disease (NID.D), e.g., avascular necrosis, osteoarthritis and arthritis secondary to a variety of diseases and anomalies;
2. Passively correctable valgus-varus deformity and moderate flexion contracture;
3. Those patients wil-h failed previous surgery where pain, deformity or dysfunction persists.
The N-K II Unicompaitmental All-Poly Tibia is intended to be used only with bone cement. The modular metal/polymer N-K II Unicompartmental Tibia and Femur are intended for use with or without bone cement.
Indications for use as stated in the FDA summary.
https://510kreport.com/device/K033810 · printed Nov 6, 2026
Cite this page
510(k) Report. “K033810: Natural-Knee II Unicompartmental Knee System.” Lineage record from FDA 510(k) data and the FDA summary. Updated Nov 3, 2026. Accessed Nov 6, 2026. https://510kreport.com/device/K033810
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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