(88 days)
The Trabecular Metal LCCK Coupled Tibial Cones are intended for use where severe degeneration, trauma, or other pathology of the knee joint indicates total knee arthroplasty. When used with the NexGen Complete Knee Solution - Legacy Constrained Condylar Knee System, the Trabecular Metal Coupled Tibial Cones are for cementless or cemented use.
The NexGen® LCCK Trabecular Metal™ Coupled Tibial Cones™ are manufactured of Trabecular Metal™, porous tantalum with titanium alloy screws and screw inserts. The proposed TM Coupled Tibial Cones intend to combine the function of TM Tibial Augments and TM Tibial Cone Augments. The TM Coupled Tibial Cone design uses the same cavitary filling geometries of the TM Tibial Cone Augment and the mating functions of the TM Tibial Augment to specifically address small to medium segmented, contained, cavitary bony defects of the proximal tibia found during revision surgery. The TM Coupled Tibial Cone design provides the use of mechanical attachment to the tibial baseplate to allow for modularity and intra-operative assembly. The design is intended to provide stability to the tibial baseplate construct after reconstruction of the proximal tibia when subjected to normal gait activities.
The provided document, K120990, describes a 510(k) premarket notification for a medical device. This type of submission focuses on demonstrating substantial equivalence to a legally marketed predicate device rather than conducting extensive new clinical studies with human participants. Therefore, many of the requested data points related to human reader studies, training sets, and expert ground truth are not applicable in this context.
Here's an analysis based on the provided document:
1. Table of Acceptance Criteria and Reported Device Performance:
| Acceptance Criteria | Reported Device Performance |
|---|---|
| Mechanical performance for normal gait activities (walking, stair ascent/decent, deep flexion) for the proposed implant needs to meet predetermined requirements. | A comparative Finite Element Analysis (FEA) study was performed to evaluate the strength of the proposed TM Coupled Tibial Cone designs across different normal gait activities (walking, stair ascent/decent and deep flexion). The results demonstrated that the proposed implant adequately meets the predetermined requirements established for its mechanical performance. This supports its substantial equivalence to the predicate devices. The submission states there are "no significant differences between the proposed NexGen® LCCK Trabecular Metal™ Coupled Tibial Cones™ and the predicates currently being marketed. Any differences in technological characteristics do not raise new issues of safety and efficacy." |
| Substantial equivalence to predicate devices regarding materials, intended use, indications for use, technological characteristics, and design features. | The NexGen® LCCK Trabecular Metal™ Coupled Tibial Cones™ have the same material, intended use, and indications for use as the previously cleared predicate devices (Zimmer's NexGen® Trabecular Metal™ Tibial Cone Augments (K102896, K031962, K053340) and Zimmer's NexGen® Complete Knee Solution - Trabecular Metal™ Augments (K024161, K040487)). This submission introduces a version of the cone augments to address a wider range of defects, but incorporates the same technological characteristics and design features as the predicate devices. |
2. Sample Size Used for the Test Set and Data Provenance:
The study referenced is a Finite Element Analysis (FEA), which is a computational simulation. Therefore, there isn't a "sample size" in the traditional sense of patient data. The "test set" would be the conditions and parameters used in the FEA model. The document does not specify the number of simulations or variations performed within the FEA.
- Data Provenance: Not applicable in the context of an FEA study comparing mechanical performance to a predicate device. This is a design and engineering analysis, not based on patient data.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts:
- Not Applicable: For an FEA study evaluating mechanical performance, "ground truth" is established through engineering principles, material properties, and validated simulation methods, not by expert human review of images or clinical data. The "experts" would be the engineers and biomechanical analysts who designed and validated the FEA model.
4. Adjudication Method for the Test Set:
- Not Applicable: Since this is an FEA study, there is no adjudication method in the context of human interpretation of results. The output of the FEA is numerical and visual data representing stress, strain, and deformation, which is then interpreted against predetermined engineering criteria.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was Done, and Effect Size:
- No: An MRMC comparative effectiveness study was not performed. This type of study is typically conducted for diagnostic or screening devices where human reader performance is a critical outcome. The K120990 submission focuses on the mechanical substantial equivalence of an orthopedic implant.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Study was Done:
- Yes, in the context of mechanical engineering: The Finite Element Analysis (FEA) can be considered a "standalone" or "algorithm only" study in that it computationally models the device's behavior under various loads without human interpretation of clinical images or data being part of the primary assessment. The FEA algorithm calculates stress and strain, and these calculations are then reviewed by engineers.
7. The Type of Ground Truth Used:
- Engineering Principles and Predicate Device Performance: The "ground truth" for the FEA study is based on established biomechanical engineering principles, material properties of the device and surrounding bone, and the known acceptable mechanical performance of the predicate devices under similar loading conditions (normal gait activities). The FEA models the real-world mechanical behavior of the device.
8. The Sample Size for the Training Set:
- Not Applicable: The FEA study does not involve a "training set" in the context of machine learning. The FEA model is built based on design specifications, material properties, and biomechanical principles.
9. How the Ground Truth for the Training Set Was Established:
- Not Applicable: As there is no training set in the machine learning sense, this question is not relevant to the K120990 submission. The parameters and assumptions of the FEA model are based on established engineering practices and validated material data.
§ 888.3565 Knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis.
(a)
Identification. A knee joint patellofemorotibial metal/polymer porous-coated uncemented prosthesis is a device intended to be implanted to replace a knee joint. The device limits translation and rotation in one or more planes via the geometry of its articulating surfaces. It has no linkage across-the-joint. This generic type of device is designed to achieve biological fixation to bone without the use of bone cement. This identification includes fixed-bearing knee prostheses where the ultra high molecular weight polyethylene tibial bearing is rigidly secured to the metal tibial base plate.(b)
Classification. Class II (special controls). The special control is FDA's guidance: “Class II Special Controls Guidance Document: Knee Joint Patellofemorotibial and Femorotibial Metal/Polymer Porous-Coated Uncemented Prostheses; Guidance for Industry and FDA.” See § 888.1 for the availability of this guidance.