Components of the Signature Orthopaedics hip replacement range are intended to replace a hip joint where bone stock is sufficient to support the implant. When a surgeon has selected prosthetic replacement as the preferred treatment, the devices are indicated for:

Non-inflammatory degenerative joint disease including osteoarthritis or avascular necrosis
Inflammatory joint disease including rheumatoid arthritis
Correction of functional deformity including congenital hip dysplasia & fracture non-union or mal-union
Traumatic injury involving the hip joint including traumatic arthritis or femoral head or neck fracture
Failed previous hip surgery including internal fixation or joint fusion, hemiarthroplasty, surface replacement, or total hip replacement
Dislocation risks (when used with SignaSure Dual Mobility System)

Signature Orthopaedics' Longboard Revision Stem is intended for individuals undergoing revision surgery of the hip only.

Signature Orthopaedics' Origin, Origin TT, Aria, Remedy, Origin-NS, Pegasus, Spartan, World, Everglade and Longboard Hip femoral stems, SignaSure Cementless Cups, Logical and World Acetabular Cups are intended for cementless fixation only.

Device Description

The Longboard Revision Stem is a femoral stem and a partially threaded distal locking screw intended for single use and cementless fixation for revision hip arthroplasties. The components are manufactured from titanium alloy as per ISO 5832-3 and ASTM F136 and the stem has a titanium alloy grit blast along the body. The Longboard Revision Stem is a symmetrical with a neck angle of 135°. The stem body is tapered and finned, while the distal tip is finless to allow for initial version adjustments. The stem neck features a 12/14 taper which allows for compatibility with Signature Orthopaedics' range of previously cleared femoral head components.

AI/ML Overview

This FDA 510(k) Clearance Letter for the Longboard Revision Hip Stem describes a medical device (an orthopedic implant), not a software or AI/ML-based device. Therefore, the questions regarding acceptance criteria and study design for performance evaluation of algorithms and AI/ML systems (e.g., sensitivity, specificity, MRMC studies, ground truth establishment by experts) are not applicable to this document.

The document focuses on demonstrating substantial equivalence to predicate devices through non-clinical performance testing for mechanical properties and material characteristics, as is standard for orthopedic implants.

Here's an analysis of the provided information relevant to the device's acceptance criteria and the study that proves it meets them, framed within the context of a physical medical device:

Acceptance Criteria and Study Proving Device Meets Acceptance Criteria

For physical medical devices like the Longboard Revision Hip Stem, acceptance criteria primarily revolve around:

Safety and Effectiveness: Ensuring the device is safe for its intended use and performs as expected.
Biocompatibility: Materials used must be compatible with the human body.
Mechanical Performance: The device must withstand anticipated physiological loads and stresses without failure for its expected lifespan.
Conformity to Standards: Compliance with established industry and regulatory standards.
Substantial Equivalence: Demonstrating that the device is as safe and effective as a legally marketed predicate device.

The study described to prove the device meets these criteria is the non-clinical performance testing and engineering evaluations.

1. Table of Acceptance Criteria and the Reported Device Performance

The document doesn't provide a precise "table" of numerical acceptance criteria in the format typically seen for AI/ML performance (e.g., "Sensitivity >= X%"). Instead, acceptance is inferred from the successful completion of specified engineering tests and adherence to industry standards, followed by a conclusion of substantial equivalence.

Acceptance Criterion (Inferred from Regulatory Requirements for Orthopedic Implants)	Reported Device Performance Summary (from document)
Mechanical Strength & Endurance: Withstand anticipated physiological loads and stresses without fracture or fatigue failure.	Non-clinical testing and engineering evaluations (FEA and physical testing) conducted on worst-case sizes. Results show that "the strength of the Signature Orthopaedics Longboard Revision Hip Stem is sufficient for their intended use and substantially equivalent to the legally marketed predicate device." Specifically, "Stem and Neck Fatigue FEA" and "Stem and Neck Fatigue Testing" were performed.
Range of Motion: Allow for functional hip joint movement.	"Range of Motion" testing was performed to verify adequate performance.
Material Biocompatibility: Materials are safe for implantation.	Manufactured from titanium alloy as per ISO 5832-3 and ASTM F136. These are standard, biocompatible implant-grade materials.
Conformity to Standards: Adherence to relevant international and national testing standards.	Testing conducted in accordance with: - ISO 21535 (Hip Joint Replacement Implants)- ASTM F2996 (FEA for Hip Femoral Stems)- ISO 7206-4 (Endurance of Stemmed Femoral Components)- ISO 7206-6 (Endurance of Neck Region)- ASTM F543 (Metallic Medical Bone Screws)
Substantial Equivalence: The device is as safe and effective as existing legally marketed predicate devices.	"The Longboard Revision Hip Stem have the same intended use and same indications for use as the predicate devices. The subject devices use the same operating principle, incorporate the same basic design, and are manufactured using the same materials as the predicate devices. Any differences do not raise new questions of safety and effectiveness as established with performance testing. The subject devices are at least as safe and effective as the legally marketed predicate devices."

Information Not Applicable/Provided for a Physical Device:

The following points are primarily relevant to software, AI/ML, or diagnostic devices, and therefore are not applicable to this 510(k) for a physical orthopedic implant:

Sample size used for the test set and the data provenance: Not applicable. Testing is primarily mechanical/physical on device samples, not on patient data.
Number of experts used to establish the ground truth for the test set and the qualifications of those experts: Not applicable. Ground truth for a physical implant is its physical behavior under load, measured by engineering methods, not expert consensus on images.
Adjudication method (e.g. 2+1, 3+1, none) for the test set: Not applicable.
If a multi reader multi case (MRMC) comparative effectiveness study was done, If so, what was the effect size of how much human readers improve with AI vs without AI assistance: Not applicable. This is for diagnostic interpretation, not an implant.
If a standalone (i.e. algorithm only without human-in-the-loop performance) was done: Not applicable. There is no algorithm here.
The type of ground truth used (expert concensus, pathology, outcomes data, etc): Not applicable in the context of image interpretation. Ground truth for this device is mechanical integrity, material properties, and functionality under specified conditions, verified by laboratory testing.
The sample size for the training set: Not applicable as there is no training set for a mechanical device.
How the ground truth for the training set was established: Not applicable.

In summary: The clearance of the Longboard Revision Hip Stem relies on non-clinical, laboratory-based mechanical and materials testing of physical device samples against established industry standards and comparison to predicate devices, to demonstrate its safety and effectiveness for its intended use, rather than on clinical data or AI/ML performance metrics.

Summary

FDA 510(k) Clearance Letter - Longboard Revision Hip Stem

Page 1

U.S. Food & Drug Administration
10903 New Hampshire Avenue
Silver Spring, MD 20993
www.fda.gov

Doc ID # 04017.08.00

August 7, 2025

Signature Orthopaedics Pty Ltd.
Declan Brazil
Managing Director
7 Sirius Road
Lane Cove West, NSW 2066
Australia

Re: K243021
Trade/Device Name: Longboard Revision Hip Stem
Regulation Number: 21 CFR 888.3353
Regulation Name: Hip Joint Metal/Ceramic/Polymer Semi-Constrained Cemented Or Nonporous Uncemented Prosthesis
Regulatory Class: Class II
Product Code: LZO, KWZ, KWL, KWY, LPH, OQI
Dated: July 21, 2025
Received: July 21, 2025

Dear Declan Brazil:

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 to devices that have been reclassified in accordance with the provisions of the Federal Food, Drug, and Cosmetic Act (the 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. Although this letter refers to your product as a device, please be aware that some cleared products may instead be combination products. The 510(k) Premarket Notification Database available at https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfpmn/pmn.cfm identifies combination product submissions. 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. Please note: CDRH does not evaluate information related to contract liability warranties. We remind you, however, that device labeling must be truthful and not misleading.

If your device is classified (see above) into either class II (Special Controls) or class III (PMA), it may be subject to 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.

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K243021 - Declan Brazil
Page 2

Additional information about changes that may require a new premarket notification are provided in the FDA guidance documents entitled "Deciding When to Submit a 510(k) for a Change to an Existing Device" (https://www.fda.gov/media/99812/download) and "Deciding When to Submit a 510(k) for a Software Change to an Existing Device" (https://www.fda.gov/media/99785/download).

Your device is also subject to, among other requirements, the Quality System (QS) regulation (21 CFR Part 820), which includes, but is not limited to, 21 CFR 820.30, Design controls; 21 CFR 820.90, Nonconforming product; and 21 CFR 820.100, Corrective and preventive action. Please note that regardless of whether a change requires premarket review, the QS regulation requires device manufacturers to review and approve changes to device design and production (21 CFR 820.30 and 21 CFR 820.70) and document changes and approvals in the device master record (21 CFR 820.181).

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); medical device reporting (reporting of medical device-related adverse events) (21 CFR Part 803) for devices or postmarketing safety reporting (21 CFR Part 4, Subpart B) for combination products (see https://www.fda.gov/combination-products/guidance-regulatory-information/postmarketing-safety-reporting-combination-products); good manufacturing practice requirements as set forth in the quality systems (QS) regulation (21 CFR Part 820) for devices or current good manufacturing practices (21 CFR Part 4, Subpart A) for combination products; and, if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR Parts 1000-1050.

All medical devices, including Class I and unclassified devices and combination product device constituent parts are required to be in compliance with the final Unique Device Identification System rule ("UDI Rule"). The UDI Rule requires, among other things, that a device bear a unique device identifier (UDI) on its label and package (21 CFR 801.20(a)) unless an exception or alternative applies (21 CFR 801.20(b)) and that the dates on the device label be formatted in accordance with 21 CFR 801.18. The UDI Rule (21 CFR 830.300(a) and 830.320(b)) also requires that certain information be submitted to the Global Unique Device Identification Database (GUDID) (21 CFR Part 830 Subpart E). For additional information on these requirements, please see the UDI System webpage at https://www.fda.gov/medical-devices/device-advice-comprehensive-regulatory-assistance/unique-device-identification-system-udi-system.

Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR 807.97). For questions regarding the reporting of adverse events under the MDR regulation (21 CFR Part 803), please go to https://www.fda.gov/medical-devices/medical-device-safety/medical-device-reporting-mdr-how-report-medical-device-problems.

For comprehensive regulatory information about medical devices and radiation-emitting products, including information about labeling regulations, please see Device Advice (https://www.fda.gov/medical-devices/device-advice-comprehensive-regulatory-assistance) and CDRH Learn (https://www.fda.gov/training-and-continuing-education/cdrh-learn). Additionally, you may contact the Division of Industry and Consumer Education (DICE) to ask a question about a specific regulatory topic. See the DICE website (https://www.fda.gov/medical-devices/device-advice-comprehensive-regulatory-

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K243021 - Declan Brazil
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assistance/contact-us-division-industry-and-consumer-education-dice) for more information or contact DICE by email (DICE@fda.hhs.gov) or phone (1-800-638-2041 or 301-796-7100).

Sincerely,

Limin Sun -S

Limin Sun, Ph.D.
Assistant Director
DHT6A: Division of Joint Arthroplasty Devices
OHT6: Office of Orthopedic Devices
Office of Product Evaluation and Quality
Center for Devices and Radiological Health

Enclosure

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FORM FDA 3881 (8/23)
Page 1 of 1
PSC Publishing Services (301) 443-6740 EF

DEPARTMENT OF HEALTH AND HUMAN SERVICES
Food and Drug Administration

Indications for Use

Form Approved: OMB No. 0910-0120
Expiration Date: 07/31/2026
See PRA Statement below.

510(k) Number (if known): K243021

Device Name: Longboard Revision Hip Stem

Indications for Use (Describe)

Non-inflammatory degenerative joint disease including osteoarthritis or avascular necrosis
Inflammatory joint disease including rheumatoid arthritis
Correction of functional deformity including congenital hip dysplasia & fracture non-union or mal-union
Traumatic injury involving the hip joint including traumatic arthritis or femoral head or neck fracture
Failed previous hip surgery including internal fixation or joint fusion, hemiarthroplasty, surface replacement, or total hip replacement
Dislocation risks (when used with SignaSure Dual Mobility System)

Signature Orthopaedics' Longboard Revision Stem is intended for individuals undergoing revision surgery of the hip only.

Type of Use (Select one or both, as applicable)

☒ Prescription Use (Part 21 CFR 801 Subpart D)
☐ Over-The-Counter Use (21 CFR 801 Subpart C)

CONTINUE ON A SEPARATE PAGE IF NEEDED.

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Page 5

510(k) SUMMARY

Manufacturer: Signature Orthopaedics Pty Ltd
7 Sirius Road
Lane Cove, NSW 2066
Australia

Device Trade Name: Longboard Revision Hip Stem

Common Name: Femoral Hip Prosthesis

Contact: Dr. Declan Brazil
Managing Director of Signature Orthopaedics

Prepared By: Signature Orthopaedics Pty Ltd
7 Sirius Road
Lane Cove, NSW 2066
Australia
Phone: +61 (2) 9428 5181
Fax: +61 (2) 8456 6065

Date Prepared: Aug 7th, 2025

Classification:

Class II per 21 CFR 888.3353: Hip joint metal/ceramic/polymer semi-constrained cemented or nonporous uncemented prosthesis (LZO)
Class II per 21 CFR 888.3310: Hip joint metal/polymer constrained cemented or uncemented prosthesis (KWZ)
Class II per 21 CFR 888.3360 Hip joint femoral (hemi-hip) metallic cemented or uncemented prosthesis (KWL)
Class II per 21 CFR 888.3390 Hip joint femoral (hemi-hip) metal/polymer cemented or uncemented prosthesis (KWY)
Class II per 21 CFR 888.3358 Hip joint metal/polymer/metal semi-constrained porous-coated uncemented prosthesis (LPH)
Class II per 21 CFR 888.3353 Hip joint metal/ceramic/polymer semi-constrained cemented or nonporous uncemented prosthesis (OQI)

K243021
Page 1 of 3

Page 6

Predicate Devices: Substantial equivalence to the following devices is claimed:

Smith & Nephew REDAPT™ Revision Femoral System (K151902) – Primary Predicate
Zimmer Biomet Arcos Interlocking Distal Stem (K100469) – Additional Predicate
Signature Orthopaedics Spartan Hip Stem (K192883) – Additional Predicate
Signature Orthopaedics Origin Hip Stem, Femoral Head, Logical PX-Series Acetabular Shell, Logical G-Series Acetabular Shell, Logical Acetabular (K121297) – Reference Device
Signature Orthopaedics World Hip Stem World Cup, World Liner (K201278) – Reference Device

Device Description:

Indications for Use:

Non-inflammatory degenerative joint disease including osteoarthritis or avascular necrosis
Inflammatory joint disease including rheumatoid arthritis
Correction of functional deformity including congenital hip dysplasia & fracture non-union or mal-union
Traumatic injury involving the hip joint including traumatic arthritis or femoral head or neck fracture
Failed previous hip surgery including internal fixation or joint fusion, hemiarthroplasty, surface replacement, or total hip replacement
Dislocation risks (when used with SignaSure Dual Mobility System)

Signature Orthopaedics' Longboard Revision Stem is intended for individuals undergoing revision surgery of the hip only.

K243021
Page 2 of 3

Page 7

Comparison of Technological Characteristics:

The subject and predicate device have nearly identical technological characteristics and the minor differences do not raise any new issues of safety and effectiveness. Specifically, the following characteristics are similar between the subject and predicates:

Indications for Use
Materials of manufacture
Structure support mechanism
Principle of operation
Sizes
Design

Performance Testing:

Non-clinical testing and engineering evaluations were conducted to verify that the performance of the Signature Orthopaedics Longboard Revision Hip Stem is adequate for anticipated in-vivo use. The following non-clinical testing was carried out on the worst-case sizes of the subject devices:

Range of Motion
Stem and Neck Fatigue FEA
Stem and Neck Fatigue Testing

Testing was done in accordance with the following testing standards:

ISO 21535 Non-active surgical implants – Joint replacement implants – Specific requirements for hip joint replacement implants
ASTM F2996 Standard Practice for Finite Element Analysis (FEA) of Non-Modular Metallic Orthopaedic Hip Femoral Stems
ISO 7206-4 Partial and total hip joint prosthesis – Part 4: Determination of endurance properties and performance of stemmed femoral components
ISO 7206-6 Partial and total hip joint prostheses – Part 6: Endurance properties testing and performance requirements of neck region of stemmed femoral components
ASTM F543 Standard Specification and Test Methods for Metallic Medical Bone Screws

The results of non-clinical testing show that the strength of the Signature Orthopaedics Longboard Revision Hip Stem is sufficient for their intended use and substantially equivalent to the legally marketed predicate device.

Substantial Equivalence:

The Longboard Revision Hip Stem have the same intended use and same indications for use as the predicate devices. The subject devices use the same operating principle, incorporate the same basic design, and are manufactured using the same materials as the predicate devices.

Any differences do not raise new questions of safety and effectiveness as established with performance testing. The subject devices are at least as safe and effective as the legally marketed predicate devices.

K243021
Page 3 of 3

Regulation Number and Section

§ 888.3353 Hip joint metal/ceramic/polymer semi-constrained cemented or nonporous uncemented prosthesis.

(a)
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.(b)
Classification. Class II.