The ELEOSTM/ELEOSx™ Limb Salvage System is indicated for resection and replacement of the proximal femur, intercalary portion of the femur, total femur, distal femur. and proximal tibia in skeletally mature patients with the following conditions: 1) Non-inflammatory degenerative joint disease such as osteoarthritis, traumatic arthritis, avascular necrosis, ankylosis, protrusion acetabuli, and painful hip dysplasia; 2) Inflammatory degenerative joint disease such as rheumatoid arthritis; 3) Correction of functional deformity; 4) Revision procedures where other treatments or devices have failed: and. 5) Treatment of fractures that are unmanageable using other techniques. The ELEOS™/ELEOSx™ Limb Salvage System is also indicated for procedures where resection and replacement of the proximal femur, intercalary portion of the femur, total femur, distal femur, and proximal tibia is required with the following conditions: 1) Patients suffering from severe arthropathy of the hip and/or knee that does not respond to any conservative therapy or better alternative surgical treatment; 2) Surgical intervention for severe trauma, revision hip or knee arthroplasties, and/or Oncology indications. 3) Metastatic diseases. The ELEOSx™ MDPB coating, where applied, is intended to reduce bacterial contamination prior to implantation resulting from deposition in the operating room on the surface of the device components. The clinical impact associated with the MDPB coating, including prevention of infection or reduction of infection risk in patients, has not been evaluated in human clinical trials. The MDPB coating is not intended to treat existing infections and does not act within or on the body.

Device Description

The Onkos Surgical ELEOSx™ Limb Salvage System consists of components that are used in the reconstruction of the lower limb. The systems include components manufactured from cobalt-chrome alloy (CoCr), titanium alloy (TAV), and ultra-high molecular weight polyethylene (UHMWPE). Non-articulating CoCr component surfaces are coated with 12-Methacryloyloxydodecyl Pyridinium Bromide (MDPB), which is intended to reduce bacterial contamination on the surface of the device components prior to implantation resulting from deposition in the operating room. Based on in vitro testing, this coating may result in immobilization and/or lysis of some challenge organisms. The MDPB coated CoCr stems are for cemented use in the reconstruction/replacement of the lower limb. The reconstruction applications are proximal femur, intercalary portion of the femur, distal femur, total femur, proximal tibia, and hinged knee. The ELEOS™ Limb Salvage components are femoral head, proximal femur, female stem, mid-section, stem, distal femur, tibial hinge component, axial pin. tibial poly spacer, tibial baseplate, malemale mid-section, resurfacing femur, proximal tibia, tapered screws, patella, stem extension, tibial wedges, and augments. Instruments included in the Onkos ELEOSx™ Limb Salvage System are used in implantation and removal of the system components.

AI/ML Overview

The provided text describes a De Novo classification request for a medical device, the ELEOSx™ Limb Salvage System, which includes a quaternary ammonium compound coating. The document focuses on regulatory information, device description, non-clinical/bench studies, and risk assessment to support its classification.

However, the input text does not describe a study involving an AI/Machine Learning device or an "algorithm only" performance study. It details the acceptance criteria and the studies that prove the mechanical, chemical, and biological performance of a physical medical implant, specifically focusing on the MDPB coating's integrity, effects on range of motion, cement interface pull-out strength, fretting and corrosion, antimicrobial performance, and physicochemical characterization.

Therefore, many of the requested items (e.g., sample size for test set, data provenance, number of experts, adjudication method, MRMC study, standalone algorithm performance, training set sample size, ground truth establishment) are not applicable to the information provided because the device in question is a physical implant, not an AI or algorithm-based system.

Below, I will extract the relevant information from the provided text regarding the acceptance criteria and the studies that prove the device meets these criteria, as described for this physical medical device.

Acceptance Criteria and Device Performance for ELEOSx™ Limb Salvage System

The acceptance criteria for the ELEOSx™ Limb Salvage System are defined by a series of non-clinical (bench) studies, biocompatibility evaluations, sterilization validation, and material characterization, with the overarching goal of demonstrating the device's safety and performance, particularly concerning the novel MDPB coating. The studies primarily aim to show that the MDPB coating does not negatively impact the device's mechanical integrity or biocompatibility, and that it effectively reduces bacterial contamination prior to implantation without affecting the body internally.

1. Table of Acceptance Criteria and Reported Device Performance:

Test Method (Acceptance Criteria Represented by "Purpose" and "Performance Criteria")	Purpose of Test	Performance Criteria	Reported Device Performance/Results
Biocompatibility Evaluation	To ensure the device materials (including MDPB coating) are safe for contact with the body.	Acceptable results per ISO 10993-1, -3, -5, -6, -10, -11, -17, -18 for cytotoxicity, intracutaneous reactivity, sensitization, material-mediated pyrogenicity, acute systemic toxicity, genotoxicity, local implantation, and chemical characterization/toxicological risk assessment.	All test methods and results were found acceptable. Minimal local tissue reactivity similar to uncoated metal. Chemical characterization found acceptable with toxicological risk assessment.
Evaluation of MDPB Coating Integrity	To demonstrate that MDPB coating does not shear off or delaminate through handling and implantation.	N/A (Method is characterization, not a pass/fail criterion as listed, but implies "remains intact").	No evidence of damage or removal of the MDPB coating from the device observed.
Range of Motion (ROM)	To assess the risk of MDPB coating contact with any articulating surfaces.	No impingement contact of MDPB-coated components. ROM equivalent to currently available non-MDPB coated limb salvage device.	No contact with MDPB-coated components under maximum ROM; ROM equivalent to the currently available non-MDPB coated limb salvage device.
Cement Interface Pull-out	To evaluate the pull-out strength of the stem/cement interface.	MDPB-coated group to have equivalent or higher pull-out strength compared to un-coated group.	MDPB-coated group had equivalent or higher pull-out strength compared to un-coated group.
Fretting and Corrosion	To demonstrate that MDPB coating does not compromise mechanical integrity.	MDPB-coated proximal femurs to have comparable performance to the control device (un-coated proximal femurs).	Similar fretting corrosion was observed in the MDPB-coated proximal femurs and the controls.
Antimicrobial Performance	To demonstrate in vitro antibacterial activity of the MDPB coating.	Demonstrated antibacterial activity based on a simulated use in vitro test method.	Information provided establishing reasonable evidence to support the understanding that the antimicrobial action of the MDPB coating is neutralized in the body and would not be expected to have meaningful antimicrobial activity within or on the body following implantation.
MDPB Coating Physicochemical Characterization	To characterize coating chemistry, thickness, density, and uniformity.	Validated fluorescein method to determine density; micro-imaging and spectroscopy for thickness & elemental composition; visual inspections for uniformity; product specification/sampling plan.	Sponsor demonstrated that biocompatibility and antibacterial performance testing are representative of worst-case performance based on coating characterization.
Sterilization Validation	To ensure the device is sterile.	Sterility Assurance Level (SAL) of 10^-6 based on VDMax25 method per ANSI/AAMI/ISO 11137-1/-2.	Gamma sterilization validated to provide SAL of 10^-6.
Pyrogenicity	To ensure the device has acceptable pyrogen levels.	Total endotoxin value less than or equal to 20 EU/device, meeting recommended limits per ANSI/AAMI ST72:2019.	All tested devices passed with a reported value of less than or equal to 20 EU/device.
Packaging and Shelf-life	To ensure package integrity, sterility, and device functionality over time.	Shelf-life of 3 months established; antibacterial performance maintained; packaging validated using ANSI/AAMI/ISO 11607-1.	Non-clinical performance testing established a shelf-life of 3 months. Antibacterial performance testing supported device performance over the proposed shelf-life. Packaging was validated.

2. Sample size used for the test set and the data provenance:

Test Sets: The document refers to various bench studies. Specific sample sizes are not detailed for each mechanical test (e.g., "stems were inserted," "proximal femurs").
Data Provenance: The studies are described as "non-clinical/bench studies," which implies laboratory testing. The text does not specify the country of origin of the data
(e.g., US, Europe, Asia) nor whether they were retrospective or prospective, as these terms are typically used for clinical data or AI model development. These are lab-based, controlled experiments.

3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts:

This is not applicable. The "ground truth" for these physical device tests is based on established engineering and material science standards (e.g., ISO standards, ANSI/AAMI standards) and direct measurements/observations in controlled laboratory environments. It does not involve expert readers interpretating images or data for AI model validation.

4. Adjudication method (e.g. 2+1, 3+1, none) for the test set:

This is not applicable. Adjudication methods like 2+1 or 3+1 are used in clinical studies or AI model validation where human interpretation and consensus are required to establish ground truth or resolve discrepancies. These bench studies rely on objective measurements and established protocols.

5. 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:

This is not applicable. An MRMC study is designed to evaluate the impact of an AI system on human reader performance, typically in diagnostic imaging. The ELEOSx™ Limb Salvage System is a physical medical implant, not an AI or diagnostic imaging device.

6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done:

This is not applicable. This question pertains to the performance of an AI algorithm in isolation. The ELEOSx™ Limb Salvage System is not an algorithm.

7. The type of ground truth used (expert consensus, pathology, outcomes data, etc.):

The "ground truth" for this device's performance is established through objective measurements and adherence to recognized international standards and test methods. For example:

Mechanical properties: Measured against established engineering specifications and comparative data to uncoated devices.
Biocompatibility: Demonstrated by passing standardized in vitro and in vivo (animal) tests (e.g., per ISO 10993 series).
Sterility and Pyrogenicity: Verified through validated sterilization processes and bacterial endotoxin testing (e.g., per ISO 11137, ANSI/AAMI ST72).
Antimicrobial Performance: Demonstrated in vitro through simulated use testing.

8. The sample size for the training set:

This is not applicable. The concept of a "training set" refers to data used to train an AI or machine learning model. This is a physical medical device. The manufacturing process and materials testing involve quality control and validation, but not machine learning training sets in the AI sense.

9. How the ground truth for the training set was established:

This is not applicable for the reasons stated above.

Summary

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DE NOVO CLASSIFICATION REQUEST FOR ELEOSXTM LIMB SALVAGE SYSTEM

REGULATORY INFORMATION

FDA identifies this generic type of device as:

Limb and joint salvage device with quaternary ammonium compound coating. A limb and joint salvage device with quaternary ammonium compound coating is a metallic implant with or without polymer bearing for bone and joint replacement. Implants are for resection and replacement of an extremity bone (including the entire bone, epiphyseal bone, metaphyseal bone, or diaphyseal bone), or an extremity bone and the surrounding joint(s) in a skeletally mature patient. The device includes a quatemary ammonium compound coating that is covalently bonded to the device. Where applied, the coating is intended to reduce microbial contamination on the surface of the device prior to implantation. The device does not contain antimicrobial agents that act within or on the body and this device type does not include combination products.

NEW REGULATION NUMBER: 21 CFR 888.3900

CLASSIFICATION: Class II

PRODUCT CODE: QZZ

BACKGROUND

DEVICE NAME: ELEOSx™ Limb Salvage System

SUBMISSION NUMBER: DEN210058

DATE DE NOVO RECEIVED: January 4, 2022

SPONSOR INFORMATION:

Onkos Surgical 77 East Halsey Rd Parsippany, NJ 07054

INDICATIONS FOR USE

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Revision procedures where other treatments or devices have failed: and.

1. Treatment of fractures that are unmanageable using other techniques.
  The ELEOS™/ELEOSx™ Limb Salvage System is also indicated for procedures where resection and replacement of the proximal femur, intercalary portion of the femur, total femur, distal femur, and proximal tibia is required with the following conditions: 1) Patients suffering from severe arthropathy of the hip and/or knee that does not respond to any conservative therapy or better alternative surgical treatment;

Surgical intervention for severe trauma, revision hip or knee arthroplasties, and/or Oncology indications.

1. Metastatic diseases
  The ELEOSx™ MDPB coating, where applied, is intended to reduce bacterial contamination prior to implantation resulting from deposition in the operating room on the surface of the device components. The clinical impact associated with the MDPB coating, including prevention of infection or reduction of infection risk in patients, has not been evaluated in human clinical trials. The MDPB coating is not intended to treat existing infections and does not act within or on the body.

LIMITATIONS

The sale, distribution, and use of the ELEOSx ™ Limb Salvage System are restricted to prescription use in accordance with 21 CFR 801.109.

PLEASE REFER TO THE LABELING FOR A COMPLETE LIST OF WARNINGS, PRECAUTIONS AND CONTRAINDICATIONS.

DEVICE DESCRIPTION

Implant Description

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extension, tibial wedges, and augments.

Proximal Femur	Intercalary	DistalFemur	Total Femur	Proximal Tibia	Hinged Knee
Image: Proximal Femur	Image: Intercalary	Image: Distal Femur	Image: Total Femur	Image: Proximal Tibia	Image: Hinged Knee

		Reconstruction Applications and Assemblies
Components	Material	ProximalFemur	Intercalary	DistalFemur	TotalFemur	ProximalTibia	HingedKnee
Femoral head	CoCr	X			X
Proximal Femur	TAV	X			X
Female Stem	CoCr		X
Mid-Section2	CoCr	X	X	X	X	X
Segmental Stem2	CoCr or TAV	X	X	X		X
Modular Collar	TAV	X		X		X
Distal Femur	CoCr			X	X
Tibial HingeComponent	CoCr andUHWMPE			X	X	X	X
Axial Pin	CoCr andUHWMPE			X	X	X	X
Tibial Poly Spacer	UHWMPE			X	X	X	X
Tibial Baseplate	TAV			X	X		X
Male-Male Mid-Section2	CoCr or TAV				X
ResurfacingFemur	CoCr					X	X
Proximal Tibia	TAV					X
Tapered Screw1	TAV			X	X	X	X
Patella1	UHWMPE			X	X	X	X
Wedges andAugments1	TAV			X	X		X
Stem Extensions1	TAV			X	X	X	X

1 These implants are optional for each procedure. The surgeon shall use his/her medical judgement to determine if these implants are necessary based on factor such as patient bone quality, joint stability, and pathology.
2 These implants are available with the ELEOSx™ antibacterial coating (MDPB).

Instrument Description

Instruments included in the Onkos ELEOSx™ Limb Salvage System are used in implantation and removal of the system components.

SUMMARY OF NONCLINICAL/BENCH STUDIES

BIOCOMPATIBILITY/MATERIALS

The non-articulating CoCr alloy components of the Onkos ELEOSxTM Limb Salvage System include a MDPB surface coating.

Biocompatibility evaluation of the subject implant device has been completed according

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to FDA's Guidance, "Use of International Standard ISO 10993-1, 'Biological evaluation of medical devices - Part 1: Evaluation and testing within a risk management process."" Biocompatibility testing for the permanent implant included cytotoxicity (ISO 10993-5). intracutaneous reactivity (ISO 10993-10), sensitization (ISO 10993-10), materialmediated pvrogenicity (ISO 10993-11), acute systemic toxicity (ISO 10993-11). genotoxicity (ISO 10993-3; bacterial reverse mutation assay, mouse lymphoma assay). All test methods and results were found acceptable.

A 52-week ovine study was conducted to evaluate systemic toxicity per ISO 10993-11:2017 and local implantation per ISO 10993-6:2016. An additional 13-week rabbit study was conducted (intramuscular and epicondylar) to supplement the ovine study and address local implantation per ISO 10993-6:2016. The totality of the implantation data supports that the test articles did not produce systemic toxicological effects and resulted in minimal local tissue reactivity, similar to the control article (uncoated metal).

Chemical characterization with exhaustive extraction in polar (neutral pH of 7 and acidic . pH of 4), mid-polar. non-polar conditions was performed per ISO 10993-18 with toxicological risk assessment per ISO 10993-17 to evaluate the reported extractables.

The Ti6Al4V (TAV) and UHMWPE components (without MDPB coating) were adequately evaluated for biocompatibility in prior marketing submissions.

The instruments included in the Onkos ELEOSx™ Limb Salvage System are made from various materials with limited (≤ 24h) contact to tissue/bone. The instruments were adequately evaluated for biocompatibility in prior marketing submissions.

STERILIZATION/PACKAGING AND SHELF-LIFE/PYROGENICITY

Sterilization

The ELEOSx™ Limb Salvage System is a single-use device provided clean and sterile to the end user. Gamma sterilization of the device has been validated to provide a Sterility Assurance Level (SAL) of 106 based on the VDMax25 method as recommended by FDA Recognized Consensus Standard series ANSI/AAMI/ISO 11137-1 ("Sterilization of health care products - Radiation - Part 1: Requirements for development, validation and routine control of a sterilization process for medical devices")/-2 ("Sterilization of health care products - Radiation - Part 2: Establishing the sterilization dose").

Packaging and Shelf-life

Implants are packaged within a 10 mil urethane sleeve, followed by an inner nylon/10)(4)(4) pouch, an outer nylon bouch, a retention insert, and a shrink-wrapped shelf box. Non-clinical performance testing established a shelf-life of 3 months. Antibacterial performance testing supported device performance over the proposed shelf-life. Packaging was validated using ANSI/AAMI/ISO 11607-1 ("Packaging for terminally

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sterilized medical devices - Part 1: Requirements for materials, sterile barrier systems and packaging systems").

Pyrogenicity

Bacterial endotoxins testing (BET) was performed to determine whether the total endotoxin value for the device met pyrogen limit specifications. All tested devices passed with a reported value of less than or equal to 20 EU/device, meeting the recommended endotoxin limits per ANSI/AAMI ST72:2019 ("Bacterial endotoxins - Test methods, routine monitoring, and alternatives to batch testing").

PERFORMANCE TESTING - BENCH

Some previous device information and performance data for the uncoated implant configurations are considered to demonstrate acceptable device-specific performance due to insignificant effect of the MDPB coating on those construct mechanical tests. A summary of those special control performance data, including evaluation of static and dynamic strength, range of motion, articulating bearing wear and bearing material, and implant disassembly as well as validation information for the reprocessing instructions for the reusable instrumentation of the device is identified in Onkos's cleared marketing applications (K211677, K203815, K203588, K203090, K180130, K161520). Additional non-clinical performance testing is provided to address the device performance due to the addition of the MDPB coating and a summary of these additional non-clinical mechanical performance evaluations is provided in Table 1:

Test	Purpose	Method	PerformanceCriteria	Results
Evaluation of MDPBCoating Integrity	To demonstrate thatMDPB coating doesnot shear off ordelaminate from thesubject devicethrough handling andimplantation.	Follow the surgicaltechnique protocol forproximal femoralreplacement, andverify pre-assemblyand post-assembly,using opticalmicroscopy, that theMDPB coatingremains intact on thedevice.	N/A – this is acharacterization of theeffect of surgicalassembly on theMDPB-coated device.	No evidence ofdamage or removal ofthe MDPB coatingfrom the deviceobserved.
Range of Motion(ROM)	To assess the risk ofMDPB coatingcontact with any ofthe ELEOSx systemarticulating surfaces.	Computer simulatedhip and knee jointmovement performedthroughout entireROM untilimpingement contact.	No impingementcontact of MDPB-coated components.	No contact withMDPB-coatedcomponents undermaximum ROM;ROM equivalent to thecurrently availablenon-MDPB coatedlimb salvage device.

Table 1: Summary of Non-clinical Mechanical Performance Evaluations

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Cement interfacePull-out	To evaluate the pull-out strength of thestem/cement interface	Stems were insertedinto cylinderssurrounded by bonecement. Once cured,stems were pulledaxially until failure.	MDPB-coated group to MDPB-coated grouphave equivalent or had higher pull-outhigher pull-out strength strength compared tocompared to un-coated un-coated group.group.
Fretting andCorrosion	To demonstrate thatthe addition of theMDPB coating doesnot compromise themechanical integrityof the limb salvageassembly.	Proximal femurs (withmaximum mid-sectionmodularity) weredistally potted andproximally loaded.The device wasfatigue tested in salineat (b)(4) N for (b)(4)cycles at a frequencyof Hz. Componentswere opticallyinspected for frettingand corrosion damageafter testing.	The MDPB-coatedproximal femurs tohave comparableperformance to thecontrol device (un-coated proximalfemurs).	Similar frettingcorrosion wasobserved in theMDPB-coatedproximal femurs andthe controls.

Antimicrobial Performance

The subject device's MDPB coating was evaluated for its antimicrobial performance based on a simulated use in vitro test method that demonstrated antibacterial activity. The subject device's MDPB coating was also evaluated for its antimicrobial resistance risk profile.

Information was provided establishing reasonable evidence to support the understanding that the antimicrobial action of the MDPB coating is neutralized in the body and would. not be expected to have meaningful antimicrobial activity within or on the body following implantation.

MDPB Coating Physicochemical Characterization

The subject device's MDPB coating was characterized and evaluated for assessment of coating physicochemical properties such as coating chemistry, thickness, density, and uniformity. Information to establish these characteristics included a detailed description of the substrate morphology and coating process, a validated fluorescein method to determine the MDPB coating density on the surface of the subject device, micro-imaging and spectroscopy techniques to determine the coating thickness and elemental compositions, appropriate visual inspections to demonstrate sufficient uniformity of the MDPB coating on the surface of the subject device, and a final product release strategy containing appropriately established product specification and sampling plan. The sponsor demonstrated that the biocompatibility and antibacterial performance testing are representative of worst-case performance of the subject device based on the coating characterization.

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LABELING

The labeling consists of the following: device description, indications for use, instructions for use including surgical steps (e.g., device selection and placement), principles of device operation. identification of device materials, contraindications, warnings, precautions, and a list of potential adverse effects. Furthermore, the sterile packaging includes a shelf-life for the device. The labeling meets the requirements of 21 CFR 801.109 for prescription devices.

RISKS TO HEALTH

The table below identifies the risks to health that may be associated with use of a limb and joint salvage device with quaternary ammonium compound coating and the measures necessary to mitigate these risks.

Risks to Health	Mitigation Measures
Antimicrobial resistance	Antimicrobial resistance analysis
Loss of implant integrity andfunction leading to revision	Non-clinical performance testingShelf life testingLabeling
Adverse tissue reaction	Animal performance testingBiocompatibility evaluationNon-clinical performance testingPyrogenicity testing
Infection	Non-clinical performance testingSterilization validationShelf life testingReprocessing validationLabeling

SPECIAL CONTROLS

In combination with the general controls of the FD&C Act. the limb and joint salvage device with quaternary ammonium compound coating is subject to the following special controls:

(1) Animal performance testing must demonstrate that the device performs as intended under anticipated conditions of use. Animal testing must include imaging, histology. and histomorphometry to assess bone formation, healing, and tissue response at relevant timepoints over the course of healing.
(2) Non-clinical performance testing must demonstrate that the device performs as intended under anticipated conditions of use and include the following:
- Evaluation of the static and dynamic performance of the implant: (i)
- Evaluation of coated implant initial fixation: (ii)
- Evaluation of coating integrity: (iii)
- Evaluation of range of motion; (iv)
- Evaluation of articulating bearing wear and bearing material; (v)

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Evaluation of implant disassembly: (vi)
(vii) Evaluation of fretting and corrosion;
(viii) Evaluation of antimicrobial performance with clinically relevant microbial species; and
(ix) Coating characterization, including a detailed description of the substrate morphology and coating process and an evaluation of coating physicochemical properties such as density, thickness, chemistry, and uniformity.
(3) An analysis must be provided that identifies and evaluates any contribution to the development and spread of antimicrobial resistance.
(4) An analysis or information must be provided to support that the antimicrobial does not act within or on the body.
(5) The patient-contacting components of the device must be demonstrated to be biocompatible.
(6) Performance data must support the sterility and pyrogenicity of the device components intended to be provided sterile.
Performance data must validate the reprocessing instructions for the reusable (7) instrumentation to be used with the device.
Performance data must support the shelf life of the device by demonstrating continued (8) sterility, package integrity, and device functionality over the identified shelf life.
(9) Labeling must include the following:
- Identification of device materials; (i)
- A shelf life: and (ii)
- (iii) Instructions for removal/revision procedures.

BENEFIT-RISK DETERMINATION

The target populations for the ELEOSx™ Limb Salvage System are high-risk patients due to associated medical co-morbidities, the magnitude of the types of surgical procedures, and the high risk of device-related and procedure-related adverse events including infection.

The sponsor has collected adequate data to assess the safety profile of the subject device and has identified that there are benefits from the use of the device. Mechanical evaluations demonstrated restoration of function, while the antimicrobial performance testing demonstrated a reduction of in vitro bacterial contamination. The risks to health, which include antimicrobial resistance, loss of implant integrity and function leading to revision, adverse tissue reaction, and infection have been mitigated by an animal safety study and other non-clinical studies as described above. A list of warnings and potential adverse effects is provided in the labeling. In conclusion, the benefits of using the subject device for its intended use/indications for use outweigh the risks to health.

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Benefits: The probable benefits of the subject device with the MDPB coating, as demonstrated by the non-clinical evaluations described above, include limb salvage and restoration of function, and reduced bacterial contamination on the surface of the device prior to implantation in a highrisk patient group.

Risks: The risks of the subject device, as listed in the Risks to Health section above, are antimicrobial resistance, loss of implant integrity and function leading to revision, adverse tissue reaction, and infection. These risks have been mitigated by the listed Mitigation Measures above, which include non-clinical performance testing, biocompatibility evaluation, pyrogenicity testing, sterilization validation, shelf-life validation, reprocessing validation, and labeling.

To address potential safety concerns related to the MDPB coating stability and effect in humans, a 522 Order for a Postmarket Surveillance Study will be issued for this device.

Patient Perspectives

This submission did not include specific information on patient perspectives for this device.

Benefit/Risk Conclusion

In conclusion, given the available information above, for the following indication statement:

The ELEOSTM/ELEOSx™ Limb Salvage System is indicated for resection and replacement of the proximal femur, intercalary portion of the femur, total femur, distal femur, and proximal tibia in skeletally mature patients with the following conditions: 1) Non-inflammatory degenerative joint disease such as osteoarthritis, traumatic arthritis, avascular necrosis, ankylosis, protrusion acetabuli, and painful hip dysplasia; 2) Inflammatory degenerative joint disease such as rheumatoid arthritis:

1. Correction of functional deformity
1. Revision procedures where other treatments or devices have failed; and,
1. Treatment of fractures that are unmanageable using other techniques.

The ELEOS™/ELEOSx™ Limb Salvage System is also indicated for procedures where resection and replacement of the proximal femur, intercalary portion of the femur, total femur, distal femur, and proximal tibia is required with the following conditions: 1) Patients suffering from severe arthropathy of the hip and/or knee that does not respond to any conservative therapy or better alternative surgical treatment: 2) Surgical intervention for severe trauma, revision hip or knee arthroplasties, and/or Oncology indications. 3) Metastatic diseases

The ELEOSx™ MDPB coating, where applied, is intended to reduce bacterial contamination prior to implantation resulting from deposition in the operating room on the surface of the device components. The clinical impact associated with the MDPB coating, including prevention of infection or reduction of infection risk in patients, has

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not been evaluated in human clinical trials. The MDPB coating is not intended to treat existing infections and does not act within or on the body.

The probable benefits outweigh the probable risks for the ELEOSx™ Limb Salvage System. The device provides benefits, and the risks can be mitigated by the use of general controls and the identified special controls.

CONCLUSION

The De Novo request for the Onkos Surgical ELEOSx™ Limb Salvage System is granted and the device is classified as follows:

Product Code: QZZ Device Type: Limb and joint salvage device with quaternary ammonium compound coating Regulation Number: 21 CFR 888.3900 Class: II

Regulation Number and Section

N/A