NATURAL-KNEE II UNICOMPARTMENTAL KNEE SYSTEM

K033810 · Centerpulse Orthopedics, Inc. · HRY · Mar 5, 2004 · Orthopedic

Device Facts

• Record ID: K033810
• Device Name: NATURAL-KNEE II UNICOMPARTMENTAL KNEE SYSTEM
• Applicant: Centerpulse Orthopedics, Inc.
• Product Code: HRY · Orthopedic
• Decision Date: Mar 5, 2004
• Decision: SESE
• Submission Type: Traditional
• Regulation: 21 CFR 888.3530
• Device Class: Class 2
• Attributes: Therapeutic

Intended Use

The Natural-Knee II Unicompartmental Knee is intended for use in: - Unicompartmental noninflammatory degenerative joint disease (NIDJD), e.g., 1. avascular necrosis, osteoarthritis and arthritis secondary to a variety of diseases and anomalies: - Passively correctable valgus-varus deformity and moderate flexion contracture; 2. - Those patients with failed previous surgery where pain, deformity or dysfunction persists. The proposed N-K II Unicompartmental All-Poly Tibia is intended to be used only with bone cement. The N-K II Unicompartmental Modular Tibia and Femur are intended for use with or without bone cement.

Device Story

Natural-Knee II Unicompartmental Knee System is a prosthetic implant for resurfacing one compartment of the knee joint. Components include a modular metal-backed tibia (wrought titanium alloy), an all-polyethylene tibia, and a femoral component. The metal-backed tibia features a symmetric baseplate with three smooth pegs for rotational stability and an optional central screw hole. The all-poly tibia utilizes a single keel with cement grooves and dovetail channels for fixation. The system is used by orthopedic surgeons in a clinical/surgical setting to treat degenerative joint disease. The device provides a conservative alternative to total knee replacement, aiming to restore joint function and reduce pain. The femoral component allows for cementless use. The system is implanted via surgical procedure, with the all-poly tibia requiring bone cement and the modular components allowing for cemented or cementless application.

Clinical Evidence

No clinical data provided; substantial equivalence is based on design, material, and intended use comparisons to legally marketed predicate devices.

Technological Characteristics

Materials: Wrought titanium alloy (tibial baseplate), polyethylene (all-poly tibia/inserts). Design: Modular metal-backed tibia (symmetric, 3 pegs, optional screw fixation) and all-poly tibia (single keel, cement grooves/dovetail channels). Fixation: Cemented (all-poly) or cemented/cementless (modular metal-backed). Sizes: 6 sizes (1-6) for tibias; modular inserts in 3 thicknesses (9, 11, 13 mm); all-poly inserts in 4 thicknesses (7, 9, 11, 13 mm).

Indications for Use

Indicated for patients with unicompartmental noninflammatory degenerative joint disease (e.g., avascular necrosis, osteoarthritis, arthritis secondary to anomalies), passively correctable valgus-varus deformity, moderate flexion contracture, or failed previous surgery with persistent pain, deformity, or dysfunction.

Regulatory Classification

Identification

A knee joint femorotibial metal/polymer semi-constrained cemented prosthesis is a device intended to be implanted to replace part of a knee joint. The device limits translation and rotation in one or more planes via the geometry of its articulating surfaces. It has no linkage across-the-joint. This generic type of device includes prostheses that consist of a femoral component made of alloys, such as cobalt-chromium-molybdenum, and a tibial component made of ultra-high molecular weight polyethylene and is limited to those prostheses intended for use with bone cement (§ 888.3027).

Predicate Devices

• Natural-Knee II Unicompartmental Knee System (K955778)
• Natural-Knee Unicompartmental Knee System (K883969)
• Natural-Knee II Total Knee System with CSTi (P940002)
• Wright Medical ADVANCE® Unicompartmental Knee (K012591)
• DePuy Preservation™ Unicompartmental Knee (K010810)
• Plus Orthopedics UC Plus™ Unicompartmental Knee (K982859)

Submission Summary (Full Text)

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## 510(k) SUMMARY

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Centerpulse Orthopedics, Inc., a division of Zimmer SPONSOR NAME: 9900 Spectrum Drive Austin, TX 78717

Audrey Swearingen CONTACT: Phone: [phone] Audrey [e-mail] E-Mail:

Natural-Knee® II Unicompartmental Knee System TRADE NAME:

Unicompartmental Knee COMMON NAME:

Unicompartmental Knees are Class II, reviewed by the CLASSIFICATION: Orthopedic Devices panel, per 21 CFR §888.3530 and 888.3535.

#### 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 II Total Knee System with CSTi (P940002) .
- Wright Medical ADVANCE® Unicompartmental Knee (K012591) .
- DePuy Preservation™ Unicompartmental Knee (K010810) .
- Plus Orthopedics UC Plus™ Unicompartmental Knee (K982859) .

#### DEVICE DESCRIPTION:

The Natural-Knee II Unicompartmental Knee System is a conservative, cost-effective alternative to total knee replacement for patients with osteoarthritis primarily confined to one compartment. The N-K II Unicompartmental Knee System is intended for resurfacing of one side of the knee joint.

The N-K II Unicompartmental Modular Metal-backed Tibia is similar to the previously cleared N-K II Unicompartmental Tibia (K955778). The wrought titanium alloy tibial baseplate is a symmetrically designed component, eliminating the need for left/right orientations. The baseplate features three smooth pegs on the underside which aid in positioning and rotational stability. A smooth surface finish is provided on the inner surface of the tibial tray to minimize the potential for polyethylene wear. A screw hole is placed in the center of the baseplate for optional screw fixation. The baseplate is available in either a porous or non-porous version.

The all-poly tibia is designed with a single keel to position the component on the tibia and increase stability. Cement grooves on both the medial and lateral side of the keel increase the anchoring effect of the keel, while a dovetail cement channel around the perimeter of the distal surface, along with a T-pattern dovetail cement channel, act to resist movement in all directions. It is to be used only with bone cement for application directly onto the patient's resected proximal tibia.

The metal-backed and the all-poly tibias are both available in 6 sizes (1-6). The modular

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033810
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metal-backed tibia will be offered in 3 thicknesses (9, 11, and 13 mm). The insert thickness reflects the total amount of bone to be resected. The all-poly insert will be available in 4 thicknesses (7, 9, 11, and 13mm), in which the thickness is measured at the thinnest point from the distal to the proximal surface of the component.

The design of the femoral component of the proposed N-K II Unicompartmental Knee System will not change. This premarket notification only seeks to obtain clearance for the addition of cementless use of the previously cleared porous-coated femur (K955778).

### INTENDED USE:

The Natural-Knee II Unicompartmental Knee is intended for use in:

- Unicompartmental noninflammatory degenerative joint disease (NIDJD), e.g., 1. avascular necrosis, osteoarthritis and arthritis secondary to a variety of diseases and anomalies:
- Passively correctable valgus-varus deformity and moderate flexion contracture; 2.
- Those patients with failed previous surgery where pain, deformity or dysfunction ന persists.

These indications for use are identical to the indications for the previously cleared Natural-Knee II Unicompartmental System (K955778) and Natural Knee Unicompartmental System (K883969).

The proposed N-K II Unicompartmental All-Poly Tibia is intended to be used only with bone cement. The N-K II Unicompartmental Modular Tibia and Femur are intended for use with or without bone cement.

# BASIS OF SUBSTANTIAL EQUIVALENCE:

Comparisons of device design features, indications for use, materials and labeling of the Natural-Knee II Unicompartmental Knee System demonstrate that it is substantially equivalent to the predicate devices listed above.

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DEPARTMENT OF HEALTH & HUMAN SERVICES

Image /page/2/Picture/1 description: The image shows the seal of the Department of Health & Human Services (HHS) of the United States. The seal features a circular border with the text "DEPARTMENT OF HEALTH & HUMAN SERVICES - USA" arranged around the perimeter. Inside the circle is a stylized eagle emblem, with three horizontal bars forming the body and wings, and a head facing left. The eagle's tail feathers are depicted as wavy lines.

Food and Drug Administration 9200 Corporate Boulevard Rockville MD 20850

MAR - 5 2004

Audrey Swearingen Manager, Regulatory Affairs Centerpulse Orthopedics, Inc. 9900 Spectrum Drive Austin, Texas 78717

Re: K033810

Trade/Device Name: Natural-Knee® II Unicompartmental Knee System Regulation Numbers: 21 CFR 888.3530 and 21 CFR 888.3535 Regulation Names: Knee joint, femorotibial, metal/polymer semi-constrained cemented Prosthesis, Knee joint, femorotibial (unicompartmental) metal/polymer porous-coated uncemented prosthesis

Regulatory Class: II Product Codes: HRY, NJD Dated: December 5, 2003 Received: December 8, 2003

Dear Ms. Swearingen:

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 10 dcvices that have been reclassified in accordance with the provisions of the Federal Food, Drug, and Cosmetic Act (Act) that do not require approval of a premarket approval application (PMA). 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 (PMA), 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 898. In 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 not mean 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 limited to: registration and listing (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 (Sections 531-542 of the Act); 21 CFR 1000-1050.

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Page 2 – Ms. Audrey Swearingen

This letter will allow you to begin marketing your device as described in your Section 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), please contact the Office of Compliance at [phone]. Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21CFR Part 807.97). You may obtain other general information on your responsibilities under the Act from the Division of Small Manufacturers, International and Consumer Assistance at its toll-free number [phone] or [phone] or at its Internet address http://www.fda.gov/cdrh/dsma/dsmamain.html

Sincerely yours,

William W. Weber, Ph.D., M.D.

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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# Indications for Use

510(k) Number (if known): K033810

Device Name: Natural-Knee® II Unicompartmental Knee System

Indications For Use: The Natural-Knee II Unicompartmental Knee is intended for use in:

- Unicompartmental noninflammatory degenerative joint disease 1. (NIDJD), e.g., avascular necrosis, osteoarthritis and arthritis secondary to a variety of diseases and anomalies;
- 2. Passively correctable valqus-varus deformity and moderate flexion contracture;
- 3. Those patients with failed previous surgery where pain, deformity or dysfunction persists.

The N-K II Unicompartmental 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.

Prescription Use X (Part 21 CFR 801 Subpart D) AND/OR

Over-The-Counter Use (21 CFR 807 Subpart C)

(PLEASE DO NOT WRITE BELOW THIS LINE-CONTINUE ON ANOTHER PAGE IF NEEDED)

Concurrence of CDRH, Offically Office Evaluation (ODE)

Wby with
KOR KOR KOR

(Division Sign-Of Division of General. Restorative. and Neurological Devices

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**510(k) Number** K033810