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:
- Noninflammatory degenerative joint disease including osteoarthritis, traumatic arthritis 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
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): - 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 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
| Acceptance Criteria (Measured Performance) | Reported Device Performance (Result and Standard) |
|---|---|
| Magnetically Induced Displacement Force | Device safely tested per ASTM F2052-15 ("Standard Test Method for Measurement of Magnetically Induced Displacement Force on Medical Devices in the Magnetic Resonance Environment"). Implicitly, met safety criteria for displacement force in an MR environment. |
| Magnetically Induced Torque | Device safely tested per ASTM F2213-17 ("Standard Test Method for Measurement of Magnetically Induced Torque on Medical Devices in the Magnetic Resonance Environment"). Implicitly, met safety criteria for magnetically induced torque in an MR environment. |
| MR Image Artifact | Device safely tested per ASTM F2119-07 (2013) ("Standard Test Method for Evaluation of MR Image Artifacts from Passive Implants"). Implicitly, demonstrated acceptable levels of image artifact in an MR environment, not obscuring diagnostic information. |
| Heating by Radiofrequency (RF) Fields (including heating in the tissue of interest) | Device safely tested per ASTM F2182-19e1 ("Standard Test Method for Measurement of Radio Frequency Induced Heating On or Near Passive Implants During Magnetic Resonance Imaging"). Additional analyses performed to address heating in the tissue of interest as indicated in the May 2021 FDA guidance document. Implicitly, heating levels remained within safe limits for patients undergoing MRI scans. |
| Overall MR Conditional Labeling (to ensure patients with the device can be safely scanned) | The labeling of the Modular Rotating Hinge Knee Systems and components has been modified to include the MR Conditional symbol and to provide the parameters under which a patient who has the device can be safely scanned. This indicates that the test results support the provision of specific, safe MRI scanning parameters for these devices, meeting the criteria for MR Conditional labeling. |
| Substantial Equivalence to Predicate Devices (based on intended use, materials, technological characteristics, and preclinical evaluation) | "Based upon a comparison of the intended use, materials, summary of technological characteristics, and preclinical evaluation, the subject Modular Rotating Hinge Knee Systems and compatible components are considered substantially equivalent to their corresponding predicate devices identified in this premarket notification." This is the overarching regulatory acceptance criterion for the 510(k) submission, confirming that the changes (MR labeling) do not alter the substantial equivalence to existing, legally marketed devices. |
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.
§ 888.3510 Knee joint femorotibial metal/polymer constrained cemented prosthesis.
(a)
Identification. A knee joint femorotibial metal/polymer constrained cemented prosthesis is a device intended to be implanted to replace part of a knee joint. The device limits translation or rotation in one or more planes and has components that are linked together or affined. This generic type of device includes prostheses composed of a ball-and-socket joint located between a stemmed femoral and a stemmed tibial component and a runner and track joint between each pair of femoral and tibial condyles. The ball-and-socket joint is composed of a ball at the head of a column rising from the stemmed tibial component. The ball, the column, the tibial plateau, and the stem for fixation of the tibial component are made of an alloy, such as cobalt-chromium-molybdenum. The ball of the tibial component is held within the socket of the femoral component by the femoral component's flat outer surface. The flat outer surface of the tibial component abuts both a reciprocal flat surface within the cavity of the femoral component and flanges on the femoral component designed to prevent distal displacement. The stem of the femoral component is made of an alloy, such as cobalt-chromium-molybdenum, but the socket of the component is made of ultra-high molecular weight polyethylene. The femoral component has metallic runners which align with the ultra-high molecular weight polyethylene tracks that press-fit into the metallic tibial component. The generic class also includes devices whose upper and lower components are linked with a solid bolt passing through a journal bearing of greater radius, permitting some rotation in the transverse plane, a minimal arc of abduction/adduction. This generic type of device is limited to those prostheses intended for use with bone cement (§ 888.3027).(b)
Classification. Class II.