# K033810: Natural-Knee II Unicompartmental Knee System

- Pathway: 510(k) (Traditional)
- Applicant: Centerpulse Orthopedics, Inc.
- Decided: Mar 5, 2004 after 88 days
- Product code: HRY (Prosthesis, Knee, Femorotibial, Semi-Constrained, Cemented, Metal/Polymer)
- Device class: 2
- Regulation: 21 CFR 888.3530
- Recalls of this device: 1 (0 Class I)
- Data: FDA decisions to Oct 25, 2026; recalls to Oct 12, 2026

## Lineage
Longest line of descent: 2 generations back to K954481 (1996). 7 ancestors in all.
20 later devices descend from it; 1 cites it directly.
0 of 28 devices in its family (counting itself) have a Class I recall.

## Predicates on the family tree (from the FDA summary)
- K955778: Natural-Knee II Unicompartmentalknee System, Intermedics Orthopedics (1996) Summary page 1.
- K883969: Uni-Knee Component of the Natural-Knee System, Intermedics Orthopedics (1989) Summary page 1.
- P940002: Natural-Knee (R) and Natural Knee (R)II W/Csti (TM), Sulzermedica (1997) Summary page 1.
- K012591: Advance Unicondylar Knee System, Wrightmedicaltechnologyinc (2001) Summary page 1.
- K010810: Depuy Preservation Unicondylar Knee Prosthesis, DePuy Orthopaedics, Inc. (2001) Summary page 1.
- K982859: UC-Plus Solution Unicondylar Knee System, Plus Orthopedics (1999) Summary page 1.

## Most influential descendants
- K133811: Restoris Porous Partial Knee System (2014), 19 descendants of its own
- K163700: Bodycad Unicompartmental Knee System (2017), 8 descendants of its own
- K181302: Bodycad Unicompartmental Knee System (2019), 7 descendants of its own
- K190439: Engage™ Partial Knee System (2019), 5 descendants of its own
- K191150: Bodycad Unicompartmental Knee System (2019), 4 descendants of its own

## Recalls of this device
- Feb 25, 2014 · Class II · Z-1252-2014: 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

## Indications for use
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.

Source page: https://510kreport.com/device/K033810
Methodology: https://510kreport.com/methodology