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The Modular Rotating Hinge Knee System is intended to be implanted with bone cement for the following conditions:

• · There is destruction of the joint surfaces, with or without significant bone deformity
• · The cruciate and/or collateral ligaments do not stabilize the knee joint
• · The ligaments are inadequate and/or the musculature is weak and/or
  · Revision is required of a failed prostheses where there has been gross instability, with or without bone loss or inadequate soft tissue

Indication for Use for Duracon Components (Cobalt Chrome & Titanium Stems, and Tibial Wedges) and Stryker Stem Components:
Indications for use of total knee replacement prostheses include:

• · noninflammatory degenerative joint disease including osteoarthritis or avascular necrosis;
• rheumatoid arthritis;
• · correction of functional deformity;
• · revision procedures where other treatments or devices have failed;
• · post-traumatic loss of joint anatomy, particularly when there is patello-femoral erosion, dysfunction or prior patellectomy: and
• · irreparable fracture of the knee.

Indications for US and Rest of World for Total Stabilizer Offset Adapter:
Indications for use of total knee replacement prostheses include:

1. Noninflammatory degenerative joint disease including osteoarthritis, traumatic arthritis or avascular necrosis;

• 2. Rheumatoid arthritis;

3. Correction of functional deformity:
4. Revision procedures where other treatments or devices have failed;
5. Post-traumatic loss of joint anatomy, particularly when there is patello-femoral erosion, dysfunction or prior patellectomy: and.
6. Irreparable fracture of the knee
   When the Total Knee Replacement Prosthesis is used with the components of the Modular Rotating Hinge Knee System, the indication for the Modular Rotating Hinge Knee with Offset Adapters is as follows:
   The Rotating Hinge Knee Systems are intended to be implanted with bone cement for the following condition(s):
7. There is destruction of the joint surfaces, with or without significant bone deformity.
8. The cruciate and/or collateral ligaments do not stabilize the knee joint.
9. The ligaments are inadequate and/or the musculature is weak and/or,
10. Revision is required of a failed prosthesis where there has been gross instability, with or without bone loss or inadequate soft tissue.

GMRS Pediatric Tibial Bearing Component:
Replacement of the distal femur and/or proximal tibia in Oncology cases where radical resection and replacement of bone is required, and in limb salvage procedures where radical resection and replacement of the bone is required. Limb salvage procedures would include surgical intervention for severe trauma, failed previous prosthesis, and/or Oncology indications. This smaller size component is intended to be used in patients with a smaller bone structure, or in skeletally immature patients. This component is intended for use with bone cement.

MRS Pediatric All Poly Tibial Component:
MRS Pediatric All Polyethylene Tibial Component is intended to be used in oncology patients where radical resection of the distal femur/proximal tibia is required. Additional indications include limb salvage procedures where radical resection and replacement of the distal femur/proximal tibia is required. Limb salvage includes surgical intervention for severe trauma, failed previous knee arthroplasties, and/or oncology indications.

The Modular Rotating Hinge (MRH) Knee System is a tri-compartmental knee system that consists of a stemmed femoral component and a stemmed tibial rotation component, connected by a set of bushings and an axle. A bumper locks this assembly. This assembly provides motion through the axle/bushing combinations in the flexion/extension plane. The articulation between the cylindrical bearing surfaces on the underside of the tibial rotating component and a tibial insert provide motion in the rotation plane. The tibial insert is assembled to a tibial stemmed tray which incorporates a longitudinal bore to accept a tibial sleeve.
The Modular Rotating Hinge Knee System is designed to provide varus/valgus stability throughout the range of motion, internal/external rotation about the tibial axis, constrained by the bearing surface radius on the tibial rotating component, and an extensive range of size, modularity and resection options. The implant system consists of a femoral component in five sizes, a tibial rotating component in five sizes, tibial crossover bearing components in various sizes, bumper inserts, tibial and femoral augmentation components and a tibial sleeve. The MRH Knee System is compatible with components of the Kinemax/Kinematic Knee System, Duracon Knee System, Howmedica Total Stabilizer Knee System, and the GMRS/MRS System.

This document is a 510(k) premarket notification for several knee joint prostheses and related components. The submission's purpose is to modify the labeling of these devices to include "MR Conditional" information. Therefore, the "device" in question for this prompt is the MR Conditional labeling for the existing knee implant systems, not a new or modified implant design itself. The study discussed relates to the safety of these existing implants in an MRI environment.

Here's the breakdown of the acceptance criteria and study information:

1. Table of Acceptance Criteria and Reported Device Performance

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

The document does not specify a "sample size" in terms of number of physical devices tested or a number of patients or images. The testing described is non-clinical testing (phantom/bench testing) performed on the device components themselves to evaluate their interaction with MRI fields.

• Sample Size: Not specified as typically understood for clinical studies (e.g., number of patients/images). This refers to physical samples of the device components or simulated constructs used in bench testing.
• Data Provenance: This is non-clinical/bench testing data, likely generated in a laboratory setting by the manufacturer or a contract testing facility. "Country of origin" for non-clinical testing is not specified, but the applicant is based in Mahwah, New Jersey, USA. The testing is retrospective in the sense that it's performed on manufactured devices, but it's a prospective evaluation of their MRI safety characteristics.

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

For this type of non-clinical, MRI safety testing, "ground truth" is not established by human experts in the same way it would be for diagnostic image interpretation. The "ground truth" is determined by the physical measurements against established safety standards (e.g., ASTM standards for magnetic force, torque, heating, and artifact). The "experts" involved would be technicians and engineers skilled in conducting these specific non-clinical tests and interpreting their results against the predefined standard limits. Their qualifications would involve expertise in materials science, biomechanics, and MRI physics, along with knowledge of the relevant ASTM standards and FDA guidance documents. The document does not specify the number or specific qualifications of these individuals.

4. Adjudication Method for the Test Set

Not applicable. Adjudication methods are typically for clinical studies where human reviewers assess data. For non-clinical, objective measurements against established standards, the test results themselves, when within the specified limits of the standards, serve as the "adjudication."

5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study

No. The document explicitly states: "Clinical testing was not required as a basis for substantial equivalence." This is a non-clinical evaluation of device safety with MRI, not a comparative study of diagnostic performance or human reader improvement.

6. Standalone (Algorithm Only Without Human-in-the-Loop Performance) Study

Not applicable. This device is a physical knee implant component, not an algorithm or AI software. The testing evaluated the physical device's interaction with MRI machines.

7. Type of Ground Truth Used

The ground truth used in this submission is based on established engineering and medical device safety standards (specifically ASTM standards F2052-15, F2213-17, F2119-07, F2182-19e1) and FDA guidance documents (e.g., "Assessment of Radiofrequency-Induced Heating in the Magnetic Resonance (MR) Environment..." and the May 2021 guidance document for heating in tissue). The "truth" is whether the measured physical properties (displacement, torque, artifact, heating) fall within the acceptable limits defined by these recognized standards and guidance.

8. Sample Size for the Training Set

Not applicable. This is not a machine learning or AI-based device, so there is no "training set." The testing performed is non-clinical for MRI safety.

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

Not applicable, as there is no training set for this type of device.

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The Kinemax® Superstabilizer (K904208), Kinematic® II Modular Condylar and Stabilizer Inserts (K871349), PCA® Modular Inserts (K894403), Kinematio® Rotating Hinge Knee (K792089), Duracon® Unicompartmental Knee (K 926231), and the Modular Replacement Metal Encapsulated Components (K952970) are intended to be used with the PCA®, Duracon®, or Kinemax® family of femoral components, tibial baseplates, and patellar components in primary or revision cemented total knee arthroplasty.

This submission describes additional UHMWPE Knee components that can be sterilized by the Duration® Stabilized process previously cleared in submission K936292, as an alternate to standard air irradiated gamma sterilization. Corresponding wear claims, previously cleared in submission K 965173 and listed below, are also applicable to these additional components. This submission includes the Kinemax® Superstabilizer (K904208), the Kinematic® II Modular Condylar and Stabilizer Inserts (K871349), the PCA Modular Inserts(K894403), the Kinematic® Rotating Hinge Knee (K792089), the Duracon® Unicompartmental Knee (K926231), and the Modular Replacement Metal Encapsulated Components (K952970). These components are intended to be used with the PCA®, Duracon®, or Kinemax® family of femoral components, tibial baseplates, and patellar components in primary or revision cemented total knee arthroplasty.

This 510(k) summary describes the Duraction® Stabilized UHMWPE Knee Components and their wear claims. The submission details three in vitro wear tests comparing the Duraction® Stabilized UHMWPE with conventionally gamma sterilized UHMWPE.

1. Table of Acceptance Criteria and Reported Device Performance

Note: The document does not explicitly state "acceptance criteria" but rather presents the results as "wear claims" based on the performed in vitro tests. The implied acceptance criterion for each test is a demonstrated reduction in volumetric wear compared to the conventionally gamma sterilized UHMWPE.

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

The document describes material-level testing rather than patient or imaging data.

• Sample Size:
  • Ring-on-Block Test: "A block of Howmedica's Duration® Stabilized UHMWPE" and "the same block of Howmedica's conventionally gamma sterilized UHMWPE." (Implies n=1 for each material type for the block test, though likely multiple replicates were used within the block).
  • Pin-on-Disk Tests (both non-aged and aged): "A 9mm thick circular disk of Howmedica's Duration® Stabilized UHMWPE" and "the same circular disk of Howmedica's conventionally gamma sterilized UHMWPE." (Implies n=1 for each material type for the disk test, though likely multiple replicates were used).
• Data Provenance: The tests are described as "in vitro tests" and "independent laboratory test(s)." The country of origin of the data is not specified, but the manufacturer is Howmedica Inc. in the USA. The data is prospective for these specific tests as they were conducted to support the submission.

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

Not applicable. This is a materials science engineering test, not a medical device performance assessment based on expert interpretation (e.g., radiology reads). The "ground truth" is measured volumetric wear.

4. Adjudication Method for the Test Set

Not applicable. This is a direct measurement of material wear, not a consensus-based assessment.

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

Not applicable. This is an in vitro materials test, not a clinical study involving human readers or AI.

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

Not applicable. This refers to the performance of the UHMWPE material itself, not an algorithm.

7. The Type of Ground Truth Used

The ground truth used for these tests is measured volumetric wear of the material samples under controlled in vitro laboratory conditions.

8. The Sample Size for the Training Set

Not applicable. This is not a machine learning or AI device that requires a training set. The "training" in this context would refer to the development and optimization of the UHMWPE material and sterilization process, which is not detailed in terms of sample sizes for individual material property tests.

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

Not applicable. (See point 8). The "ground truth" for material development would involve various material characterization techniques and performance testing during the R&D phase, but this specific 510(k) focuses on the final wear claims derived from the described in vitro tests.

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