(76 days)
Relief of pain and restoration of knee function following the effects of osteo-, rheumatoid and inflammatory arthritis, post-trauma disease effects, avascular necrosis, and total knee revision with or without varus, valgus or flexion deformity.
The tibial and femoral components are intended for use only with bone cement.
The devices which are the subject of this submission constitute a line extension to the previously cleared Nuffield Total Knee System which has been on the market since 1989.
This submission addresses those Nuffield Total Knee System devices which are plasma sprayed.
The devices restore knee function in patients with degenerative rheumatoid or osteoarthritis, and are suitable for primary arthroplasty or revision surgery.
The plasma coated devices which are the subject of this submission are:
- i. NTK Femurs (stemmed, stem-less and pegged)
- NTK Tibias (stemmed) ii.
- iii. Patellas
These devices are used in conjunction with previously cleared NTK devices, ie UHMPE Tibial Inserts, all-UHMWPE Tibias and Patellas.
The devices which are the subject of this submission are manufactured from cobalt-chrome alloy and are plasma sprayed; the plasma coating provides an increased surface roughness to act as a key for mechanical interlock with PMMA Bone Cement.
Although the Nuffield Total Knee is designed to spare the posterior cruciate ligament, the stability of the replacement relies on neither the anterior cruciate ligament and the devices can be used when both ligaments are absent.
The Plasma Coated Nuffield Total Knee System is intended for use ONLY with bone cement.
This document is a 510(k) summary for the Nuffield Total Knee System and primarily focuses on establishing substantial equivalence to previously marketed devices. It does not contain the kind of detailed information about acceptance criteria, specific performance metrics, or study designs that would be used to prove a device meets those criteria, as typically found in a clinical trial report or a more comprehensive technical submission.
The document discusses mechanical test data as support for safety and effectiveness, and mentions clinical use outside the United States for eight years with no post-operative problems reported. However, it does not provide the specifics needed to complete the requested table and study details.
Therefore, I cannot fulfill your request for:
- A table of acceptance criteria and reported device performance: This document states the device is "substantially equivalent" based on material, design principles, and intended use, but it does not specify quantitative acceptance criteria or performance metrics (e.g., success rates, complication rates, implant survival rates with thresholds).
- Sample size used for the test set and data provenance: The document mentions "extensive mechanical test data" but provides no details on sample sizes or specific tests conducted. For clinical use, it mentions "eight years" of use outside the US but does not specify a patient sample size or the countries of origin for this data.
- Number of experts used to establish ground truth and qualifications: This information is not present.
- Adjudication method: This information is not present.
- MRMC comparative effectiveness study: This document does not discuss such a study or any effect size related to AI assistance, as the device is a knee implant, not an AI-powered diagnostic tool.
- Standalone algorithm performance: This is not applicable to a knee implant.
- Type of ground truth used: For mechanical tests, the ground truth would be physical measurements. For clinical use, it would be patient outcomes, but no details on how this was assessed are provided.
- Sample size for the training set: Not applicable, as this is not an AI/ML device.
- How ground truth for the training set was established: Not applicable.
However, I can extract the following relevant information about the basis for clearance from the provided text:
Basis for Substantial Equivalence and Safety/Effectiveness (as presented in the document):
- Predicate Devices: Duracon Knee System (Howmedica, US since 1993) and Nuffield Total Knee System (Corin Medical, US since 1993).
- Reasons for Substantial Equivalence:
- All are four-part knees utilizing cobalt chrome alloy femoral and tibial components, ultra high molecular weight polyethylene tibial inserts, and metal-backed/all-polyethylene patella components.
- All components have a range of sizes and differing thicknesses of polyethylene.
- All are designed for cemented use ONLY.
- All contain within the range an all-polyethylene monoblock tibial component for low demand patients.
- Evidence for Safety and Effectiveness (General Mention):
- "extensive mechanical test data confirming the devices' safety and effectiveness." (No specific criteria or results provided in this summary).
- "The Plasma Coated Nuffield Total Knee System has been in clinical use outside the United States for eight years and no post-operative problems have been reported." (No specific study details, sample size, or follow-up duration provided).
In summary, this 510(k) document is a declaration of intent to market and a rationale for substantial equivalence. It does not provide the detailed study results and acceptance criteria typically found in reports designed to prove a device meets specific performance criteria through a rigorous study, especially in the context of AI/ML or comparative clinical trials.
§ 888.3560 Knee joint patellofemorotibial polymer/metal/polymer semi-constrained cemented prosthesis.
(a)
Identification. A knee joint patellofemorotibial polymer/metal/polymer semi-constrained cemented 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 includes prostheses that have a femoral component made of alloys, such as cobalt-chromium-molybdenum, and a tibial component or components and a retropatellar resurfacing component made of ultra-high molecular weight polyethylene. This generic type of device is limited to those prostheses intended for use with bone cement (§ 888.3027).(b)
Classification. Class II.