(84 days)
The CONSENSUS® KNEE SYSTEM Primary Knee is designed as a system and is not intended for substitution of components from other systems.
- A. Primary intervention of rheumatoid arthritis, osteoarthritis, post-traumatic arthritis, or degenerative arthritis.
- B. Failed osteotomy or unicompartmental replacements.
- C. Replacement of unsatisfactory cemented or press-fit knee components when sufficient bone stock exists.
- D. The porous coated (CoCr beads with Titanium) components may be used with or without cement.
The Consensus Total Knee System (CKS) is a primary fixed-bearing total knee system that has been on the market since the mid-1990's.
The CKS has been designed to replicate the natural anatomy of the knee in order to restore knee function. It has been developed to preserve and utilize healthy ligamentous structures. For cases where the soft tissues are not functional, the PCL substituting tibial inserts or the posterior stabilized system are available for increased stability.
The CKS incorporates femoral, tibial, and patellar components and all associated instrumentation needed for implantation. The CKS can be used for total knee replacement with posterior cruciate ligament (PCL) retaining or substituting.
The femoral components are provided in left and right side versions and are designed to replicate natural kinematic motion between the femur, tibia and patella. The Consensus femoral component is designed to provide uniform contact zones in the coronal plane throughout the range of motion when the knee is properly aligned. The femoral component is also designed with a large distal radius to optimize contact areas and reduce contact stress. The trochlear groove in the femur is designed to allow the load from the patella to be evenly distributed on the femur with adequate lateral constraint.
The CKS metallic components are available in non-porous and porous coated variants for cemented use and in a porous coated (CoCr beads with Titanium) version for uncemented use.
This document describes the non-clinical performance data for the Consensus® Knee System Line Extensions. The data focuses on material properties and mechanical performance rather than AI or human reader studies.
Here's the breakdown of the requested information based on the provided text, with an emphasis on addressing the relevant sections and noting where information is not applicable:
1. A table of acceptance criteria and the reported device performance
| Specification | Acceptance Criteria | Verification Results |
|---|---|---|
| Porous Coating: CoCr beads with Ti coating | ||
| Microstructure of the modified surface | N/A (Detailed parameters are reported, no specific acceptance criteria) | Bead to Bead Neck Diameter 0.33 mm |
| Pore Size 0.432 mm | ||
| Volume % Porosity 37% | ||
| Coating Thickness 0.889 mm | ||
| Corrosion of the modified surface | Equal to or improved corrosion resistance when compared with CoCr beads using ASTM F746 & G61 | Critical Potential Breakdown Potential |
| CoCr Beads 1290 mV 1200 mV | ||
| Ti Coated CoCr Beads 1315 mV 1200 mV | ||
| Static tensile strength | The static tensile strength will exceed 20 MPa. | Static Tensile Strength of 58.32 MPa |
| Static shear strength | The static shear strength will exceed 20 MPa. | Static Shear Strength of 58.32 MPa |
| Shear fatigue strength | The shear fatigue strength will exceed 10 million cycles. | 10 million cycles achieved with a strength of 13.78 MPa |
| Rotating beam fatigue strength | The rotating beam fatigue strength will exceed 10 million cycles. | 10 million cycles achieved with a strength of 206.7 MPa |
| Excessive abrasion | N/A (Results are reported, no specific acceptance criteria defined) | 200N load: Avg. mass loss 0.006 g; Avg. thickness loss 6% |
| 1500N load: Avg. Mass loss 0.179 g; Avg. thickness loss 23% | ||
| RLP Femoral Components | ||
| Articulating surface of the RLP components | Similar contact area and surface stress distributions. | RLP had the same contact area as the original CKS. The PS RLP matches the articulating surface of the RLP. |
| Size 0 Tibial Base Plate and Insert | ||
| Size 0 tibial baseplate/insert assembly push-in/push-out force | Similar push-in/push-out loads when compared with existing baseplate/insert combinations. | Minimum push-out load was 428 lbs with failure mode being deformation of anterior snap recess in poly insert; Similar to other insert/baseplate combinations. Components can be easily inserted by hand. |
| Thicker Tibial Insert | ||
| Insert thickness per FDA Guidance Jan. 16, 2003 | Insert thickness must be >6mm. | Insert thickness was greater than 6mm. |
| Porous Coated Metal Backed Patella | ||
| Articulating surface of the porous coated metal backed patella | Identical articulating surface. | Articulating surface of the porous coated metal backed patella is identical to existing patella. |
| Mating geometry between the UHMWPE and metal back of the porous coated metal backed patella | Identical mating geometry. | The mating geometry of the porous coated metal backed patella is identical to the existing metal backed patella. |
The remaining information requested is largely not applicable (N/A) to this specific type of device and study. The provided document describes a 510(k) submission for line extensions of a knee prosthetic system, focusing on non-clinical performance data related to material properties, mechanical strength, and design conformity. It does not involve any AI, diagnostic imaging, or human reader performance studies.
Here's an explanation for each point:
2. Sample sized used for the test set and the data provenance (e.g. country of origin of the data, retrospective or prospective)
- Sample Size: The document does not specify a "sample size" in the context of clinical trials or data sets for an AI model. For mechanical testing, the number of samples tested for each specification is not explicitly stated, although it's implied that multiple samples were tested to achieve "Avg. mass loss," etc.
- Data Provenance: N/A. This is non-clinical mechanical and material testing, not data collected from human subjects or from a specific geographical origin. It's likely laboratory testing.
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts (e.g. radiologist with 10 years of experience)
- N/A. This study does not involve expert evaluation for establishing ground truth as it's not a diagnostic or AI-based device. The "ground truth" here refers to the physical properties and performance metrics measured in a lab setting according to established standards.
4. Adjudication method (e.g. 2+1, 3+1, none) for the test set
- N/A. Adjudication methods are relevant for studies involving human interpretation or clinical outcomes, which is not the case here.
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
- N/A. This is not an AI-assisted diagnostic or interpretation device.
6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done
- N/A. This device does not involve any algorithm or AI requiring standalone performance evaluation.
7. The type of ground truth used (expert consensus, pathology, outcomes data, etc)
- The "ground truth" for this device's performance is based on objective engineering and material science standards and measurements. This includes:
- ASTM standards (e.g., F746 & G61 for corrosion).
- Pre-defined mechanical thresholds (e.g., static tensile strength > 20 MPa, fatigue strength > 10 million cycles).
- Physical design specifications (e.g., "Identical articulating surface," "Insert thickness must be >6mm").
8. The sample size for the training set
- N/A. There is no AI or machine learning model, so no training set is applicable.
9. How the ground truth for the training set was established
- N/A. As there is no training set, this question is not applicable.
§ 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.