The OrthAlign Plus® System is a computer-controlled system intended to assist the surgeon in determining reference alignment axes in relation to anatomical and instructures during stereotactic orthopedic surgical procedures. The OrthAlign Plus® System facilitates the accurate positioning of implants, relative to these alignment axes. The system aids the surgeon in controlling leg length and offset discrepancies in Total Hip Arthroplasty.

Example orthopedic surgical procedures include but are not limited to:

Total Knee Arthroplasty
· Total Hip Arthroplasty: Anterior/Posterior
· Unicompartmental Knee Arthroplasty: Tibial transverse resection

Device Description

The OrthAlign Plus® System is a non-invasive computer assisted surgical navigation system for use in knee and hip arthroplasty procedures. The OrthAlign Plus® System is configured to detect, measure, and display angular and positional measurement changes in a triaxial format. The OrthAlign Plus® System utilizes a palm-sized computer module and reference sensor to generate positional information in orthopedic procedures providing a sequence of steps for registration of anatomical landmarks, calculation of mechanical axes, and positioning of instruments relative to the mechanical axes.

The OrthAlign Plus® System comprises a single use computer module and reusable instrumentation.

AI/ML Overview

Here's a breakdown of the acceptance criteria and study information for the OrthAlign Plus System, based on the provided text:

1. Table of Acceptance Criteria and Reported Device Performance

The document does not explicitly state quantitative acceptance criteria (e.g., "accuracy must be within X degrees"). Instead, it describes performance testing that "confirms that the OrthAlign Plus® System can be used according to its intended use" and "meets design input requirements." The performance is reported in terms of general accuracy and reliability.

Acceptance Criteria (Implied)	Reported Device Performance
Integrity of software code and functionality	Software verification and validation ensured integrity, functionality, and reliability.
System meets design input requirements (clinical utility)	Customer requirements validated with an advising surgeon.
Accuracy of leg length and offset measurement	Bench testing with mechanical fixtures and foam models verified leg length and offset measurement accuracy.
Accuracy of scale reader measurement	Bench testing with mechanical fixtures and foam models verified updated scale reader measurement accuracy.

2. Sample Size Used for the Test Set and Data Provenance

The document does not provide specific sample sizes for the test set used in the performance studies. It mentions "bench testing with mechanical fixtures and foam models," which implies in-vitro testing rather than human subject data.

Sample Size (Test Set): Not specified (implied to be an unspecified number of mechanical fixtures and foam models).
Data Provenance: In-vitro (bench testing). No country of origin is specified, but the applicant is US-based. The testing is retrospective in the sense that it's performed on existing models, not prospective patient studies.

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts

The document mentions "Customer requirements validation with an advising surgeon," implying at least one expert was involved in validating clinical utility. However, it does not specify the number of experts for establishing ground truth for the accuracy tests (leg length/offset, scale reader). For the bench tests, the "ground truth" would be the known, precisely measured values of the mechanical fixtures and foam models, rather than expert consensus on anatomical structures.

Number of Experts: At least one "advising surgeon" for customer requirements validation.
Qualifications of Experts: "Advising surgeon" (specific qualifications like years of experience or subspecialty are not provided).

4. Adjudication Method for the Test Set

The document does not describe an adjudication method for the performance testing. For bench testing with mechanical fixtures, adjudication in the sense of reconciling differing expert opinions on a common case would not be applicable, as the expected values are mechanically determined. For the customer requirements validation, it's likely a qualitative assessment of whether the system met the surgeon's expectations.

Adjudication Method: Not applicable for accuracy testing; not specified for customer requirements validation.

5. If a Multi Reader Multi Case (MRMC) Comparative Effectiveness Study was done

No, a Multi-Reader Multi-Case (MRMC) comparative effectiveness study was not explicitly mentioned or described. The performance data focuses on system accuracy and validation against design requirements, not on the improvement of human readers (surgeons) with or without AI assistance.

MRMC Study Done: No.
Effect Size with AI vs. Without AI Assistance: Not applicable, as no MRMC study was performed.

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

The performance testing described, particularly the "System accuracy testing: bench testing with mechanical fixtures and foam models to verify leg length and offset and updated scale reader measurement accuracy," represents a form of standalone testing of the algorithm's output against a known physical ground truth. While the overall system is "computer-assisted surgical navigation" (implying human-in-the-loop during actual surgery), the accuracy verification of its measurements on models is essentially a standalone evaluation of its core calculation capabilities.

Standalone Performance Done: Yes (accuracy testing on mechanical fixtures and foam models).

7. The Type of Ground Truth Used

Ground Truth Type:
- Mechanically determined values: For the "system accuracy testing" of leg length, offset, and scale reader measurements, the ground truth was derived from the precisely known measurements of mechanical fixtures and foam models.
- Design input requirements/Clinical utility: For "customer requirements validation," the ground truth was the satisfaction of predefined design input requirements and the system's utility as assessed by an advising surgeon.

8. The Sample Size for the Training Set

The document primarily describes a device modification (Special 510(k)) and performance testing for that modification. It does not provide information about a "training set" for the algorithms. Given the nature of the device as a "computer-assisted surgical navigation system" that detects, measures, and displays angular and positional changes using inertial sensors, microcontrollers, and digital signal processors, it's less likely to involve a large-scale machine learning training dataset in the same way an image-based AI diagnostic device would. Its "algorithms" convert raw sensor outputs into spatial coordinates.

Sample Size (Training Set): Not specified.

9. How the Ground Truth for the Training Set Was Established

As no training set is explicitly mentioned or described, the method for establishing its ground truth is also not provided. The system's operation appears to be based on physical principles and sensor data processing rather than learning from a large, annotated dataset.

Summary

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Food and Drug Administration 10903 New Hampshire Avenue Document Control Center - WO66-G609 Silver Spring, MD 20993-0002

July 11, 2017

OrthAlign, Inc. David Vancelette Sr. Director OA/RA 120 Columbia. Suite 500 Aliso Viejo, California 92656

Re: K171780

Trade/Device Name: OrthAlign Plus System Regulation Number: 21 CFR 882.4560 Regulation Name: Stereotaxic Instrument Regulatory Class: Class II Product Code: OLO Dated: June 14, 2017 Received: June 15, 2017

Dear David Vancelette:

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 (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. 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.

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

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related adverse events) (21 CFR 803); 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.

If you desire specific advice for your device on our labeling regulation (21 CFR Part 801), please contact the Division of Industry and Consumer Education at its toll-free number (800) 638-2041 or (301) 796-7100 or at its Internet address

http://www.fda.gov/MedicalDevices/ResourcesforYou/Industry/default.htm. Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR Part 807.97). For questions regarding the reporting of adverse events under the MDR regulation (21 CFR Part 803), please go to

http://www.fda.gov/MedicalDevices/Safety/ReportaProblem/default.htm for the CDRH's Office of Surveillance and Biometrics/Division of Postmarket Surveillance.

You may obtain other general information on your responsibilities under the Act from the Division of Industry and Consumer Education at its toll-free number (800) 638-2041 or (301) 796-7100 or at its Internet address

http://www.fda.gov/MedicalDevices/ResourcesforYou/Industry/default.htm.

Sincerely,

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for

Mark N. Melkerson Director Division of Orthopedic Devices Office of Device Evaluation Center for Devices and Radiological Health

Enclosure

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Indications for Use

510(k) Number (if known)

K171780

Device Name OrthAlign Plus System

Indications for Use (Describe)

Example orthopedic surgical procedures include but are not limited to:

Total Knee Arthroplasty
· Total Hip Arthroplasty: Anterior/Posterior
· Unicompartmental Knee Arthroplasty: Tibial transverse resection

Type of Use (Select one or both, as applicable)
Registration Under Part 21 CFR 801, Subpart D
Custom Use, Under 21 CFR 801, Subpart C

Prescription Use (Part 21 CFR 801 Subpart D)

| | Over-The-Counter Use (21 CFR 801 Subpart C)

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1. 510(K) SUMMARY

This 510(k) summary is being submitted in accordance with the requirements of SMDA 1990 and 21 CFR 807.92(c).

DATE	June 14, 2017
APPLICANT	OrthAlign, Inc.120 Columbia, Suite 500Aliso Viejo, CA 92656Tel: (949) 715-2424Fax: (949) 831-9500
OFFICIALCORRESPONDENT	David VanceletteOrthAlign, Inc.120 Columbia,Suite 500Aliso Viejo, CA 92656dvancelette@orthalign.comTel: (858) 692-0335Fax: (949) 831-9500
TRADE NAME	OrthAlign Plus® System
COMMON NAME	Stereotaxic Instrument
DEVICECLASSIFICATION	Class II, 21 CFR §882.4560
PRODUCT CODES	OLO: Orthopedic Stereotaxic Instrument
PREDICATE DEVICE	OrthAlign Plus® System (K162962)
SUBMISSION TYPE	Special 510(k): Device Modification. The subjectdevice is a modification to the previously clearedOrthAlign Plus® System (K162962).

SUBSTANTIALLY EQUIVALENT TO:

The OrthAlign Plus® System is substantially equivalent to the previously cleared OrthAlign Plus® System (K162962).

DESCRIPTION OF THE DEVICE SUBJECT TO PREMARKET NOTIFICATION:

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registration of anatomical landmarks, calculation of mechanical axes, and positioning of instruments relative to the mechanical axes.

In knee arthroplasty procedures, the device assists the surgeon in:

Establishing the mechanical axis of the femur. determining the varus/valgus and . the flexion/extension angle of the cutting block relative to the femur.
Establishing the mechanical axis of the tibia, determining the varus/valgus angle and ● the posterior slope angle of the cutting block relative to the tibia.

In hip arthroplasty procedures, the device assists the surgeon in:

. Establishing the orientation of the anterior pelvic plane and determining the inclination angle and the anteversion angle of the shell impactor relative to the anterior pelvic plane, or to the anterior pelvic plane adjusted for pelvic tilt.
Measuring the intraoperative change in leg length and offset.

In unicompartmental knee arthroplasty procedures, the device assists the surgeon in:

Establishing the mechanical axis of the tibia, determining the varus/valgus angle and ● the posterior slope angle of the cutting block relative to the tibia, for the transverse resection.
The OrthAlign Plus® System comprises a single use computer module and reusable instrumentation.

INDICATIONS FOR USE:

The OrthAlign Plus System has the same indications for use as the previously cleared OrthAlign Plus® System (K162962).

The Indications for Use are as follows:

OrthAlign Plus® System:

The OrthAlign Plus® System is a computer-controlled system intended to assist the surgeon in determining reference alignment axes in relation to anatomical and instrumentation structures during stereotactic orthopedic surgical procedures. The OrthAlign Plus® System facilitates the accurate positioning of implants, relative to these alignment axes. The system aids the surgeon in controlling leg length and offset discrepancies in Total Hip Arthroplasty.

Example orthopedic surgical procedures include but are not limited to:

Total Knee Arthroplasty ●
Total Hip Arthroplasty: Anterior/Posterior ●
Unicompartmental Knee Arthroplasty: Tibial transverse resection

TECHNICAL CHARACTERISTICS (COMPARED TO PREDICATE):

The OrthAlign Plus® System was cleared under K162962. The OrthAlign Plus® System

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comprises a single use computer module, a reusable reference sensor, a reusable laser module, a reusable femoral jig, a reusable tibial jig, a reusable posterior hip jig and a reusable anterior hip jig. The device utilizes algorithms to convert sensor outputs into spatial coordinates, providing graphical and numerical representation of instruments and anatomy on the user display screen.

The OrthAlign Plus® System is being updated for the total hip arthroplasty: posterior approach to include navigation of the shell impactor to the table (or coronal) reference plane, and to enable the measurement of intraoperative change in leg length and offset using a laser to guide repositioning of the leg as in the previously cleared predicate device OrthAlign Plus® System (K162962) when used for total hip arthroplasty: anterior approach. All other features and principles of operation remain unchanged.

PERFORMANCE DATA:

Device performance testing confirms that the OrthAlign Plus® System can be used according to its intended use. The OrthAlign Plus® System has been verified and validated according to OrthAlign's procedures for product design and development. Performance testing addressed the new functionality and surgical procedure steps. Performance testing included:

. Software verification and validation to ensure the integrity of the code and functionality and reliability of the software in various use sequences.
. Customer requirements validation with an advising surgeon to validate the system meets design input requirements for its functions in a simulated use environment.
. System accuracy testing: bench testing with mechanical fixtures and foam models to verify leg length and offset and updated scale reader measurement accuracy.

This testing regime demonstrates that the subject device is as effective, and performs as well as the predicate device. This testing regime demonstrates that the subject device is substantially equivalent to the legally marketed predicate device, for its intended use in facilitating the accurate measurement of intraoperative change in leg length and offset and navigation of the acetabular shell impactor relative to the anterior pelvic plane established by the table reference frame, in THA, posterior approach.

The information provided by OrthAlign in this 510(k) application confirms that the modified OrthAlign Plus® System is substantially equivalent to predicate device, the OrthAlign Plus® System (K162962).

BASIS FOR DETERMINATION OF SUBSTANTIAL EQUIVALENCE:

A technological comparison and bench testing demonstrate the substantial equivalence of the OrthAlign Plus® System to the predicate device.

The subject device is identical to the predicate OrthAlign Plus® System (K162962), with the following exceptions:

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The subject device allows for the navigation of the acetabular shell impactor relative to ● the anterior pelvic plane established by the table reference frame, in THA, posterior approach.
. The subject device uses a laser to facilitate repositioning of the leg and single point femur registration for the measurement of intraoperative changes in leg length and joint offset in THA, posterior approach.

The table below summarizes the main features of the subject device as compared to the predicate device.

Feature or Principle	ModifiedDevice	Predicate OrthAlign Plus System (K162962)
Materials	Identical	• 17-4 PH Stainless Steel H900• 316L Stainless Steel• 455 Stainless Steel• 455 Stainless Steel• 300 Series Stainless Steels• Nitronic 60• Solvay Radel R-5000• Solvay Radel R-5100• Solvay Radel R-5500• POM C Acetal Copolymer• Polyester, Autoflex-EBA• Lexan HP1-7H8D330• Internal electronics
Control Mechanism -shell impactor navigation	Identical	• Computer measurement of the shell impactor's orientationduring acetabular shell implantation.
	Identical	• Computer displayed anteversion and abduction angles for theshell impactor.
Control Mechanism - leglength & offset changemeasurements	Identical	• Computer displayed length (superior-inferior) and offset(medial-lateral) changes.
	Identical	• Computer calculation of the intraoperative change in positionof the femur.
Operating Principles
Computer generationof positionalinformation	Identical	Uses inertial sensors, microcontroller and digital signalprocessor to generate positional information, based on physicalpositions of registration instruments.
Feature or Principle	ModifiedDevice	Predicate OrthAlign Plus System (K162962)
Registration ofanatomy	Identical	Electronics attached to movable instruments, placed in specifiedprocedural positions for recording sensor data.
Femur registration	Identical tothe predicate'santeriorapproach	• Physically registers a fiduciary plate: instrument temporarilyattaches to the femur.• Anterior approach: physically registers a fiduciary point:instrument attached to the femur.
Leg positioning	Identical tothe predicate'santeriorapproach	• Posterior approach: visual positioning and registration of areference plane used to locate leg.• Anterior approach: Laser crosshair pattern used to locate leg.
Main SystemComponents	IdenticalIdenticalIdenticalIdenticalIdentical	• Single-use computer unit• Navigation software• Reusable instrument set• Registration instruments• Acetabular Shell Impactor
User Interface	Identical	Integrated graphical user interface, on single-use unit thatattaches to instrumentation.
Energy Type	Identical	• Navigation unit, reference sensor and laser module: DCbattery power.• Instruments: manual positioning and manipulation.
Sterilization	Identical	Navigation unit: EO sterilization.Instruments: autoclave sterilization
Biocompatibility	Identical	Per ISO 10993-1, External Communicating Device,Tissue/Bone/Dentin Communicating, with subsystems that havedirect and potential indirect contact for a limited contact duration(< 24 hours)
Patient interface	Identical	Instrument fixation to bone with pins or screws. Probeindications of acetabular anatomy.
Environmentalspecifications	Identical	Specified storage and operating environments for typicaltransport and surgical environments.

Table 1. OrthAlign Plus® System Comparison to Predicate

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Regulation Number and Section

§ 882.4560 Stereotaxic instrument.

(a)
Identification. A stereotaxic instrument is a device consisting of a rigid frame with a calibrated guide mechanism for precisely positioning probes or other devices within a patient's brain, spinal cord, or other part of the nervous system.(b)
Classification. Class II (performance standards).