(86 days)
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
| Acceptance Criteria (Implied) | Reported Device Performance (Reduction in Volumetric Wear) | Study Type | Articulating Counterface | Lubricant | Cycles (Duration) |
|---|---|---|---|---|---|
| Significant Reduction in Volumetric Wear (vs. conventionally sterilized) | 30% reduction | Ring-on-Block | CoCr circular disk | Bovine calf serum | Over 5 million cycles |
| Significant Reduction in Volumetric Wear (vs. conventionally sterilized) | 68% reduction | Pin-on-Disk | CoCr cylindrical pin (1" spherical end) | Bovine calf serum | Over 4 million cycles |
| Significant Reduction in Volumetric Wear after aging (vs. aged conventionally sterilized) | 91% reduction | Pin-on-Disk (Aged) | CoCr cylindrical pin (1" spherical end) | Bovine calf serum | Over 2.5 million cycles (after 23 days simulated aging) |
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.
§ 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.