(80 days)
The Exeter All Plastic Acetabular Component (previously cleared in K936132) is intended to be used for primary and secondary reconstruction of the bearing surface of the acetabulum as a result of painful and/or severly disabled hip joints due to osteoarthritis, rheumatoid arthritis, post-traumatic arthritis or revision of a failed acetabular component.
The Howmedica® Bipolar Prosthesis, Centrax® (previously cleared in K855231) is intended to be used in conjunction with a femoral stem component for the reconstruction of a femoral head damaged by fresh fracture, non-union, aseptic necrosis of the head and neck, or by osteoarthritis or post-traumatic arthritis.
This submission describes additional UHMWPE acetabular components that can be sterilized by the Duration® Stabilized process previously cleared in submission K934060, as an alternate to standard air irradiated gamma sterilization. The additional components are the Exeter All Plastic Acetabular Component (K936132) and the Howmedica® Bipolar Prosthesis, Centrax® (K855231). Corresponding wear claims, previously cleared in submission K 963612 and listed below, are also applicable to these additional components.
The provided document describes wear claims for Duration® Stabilized UHMWPE Acetabular Components through in vitro testing. It does not detail specific acceptance criteria in a quantitative manner (e.g., "device must achieve X performance in Y metric"). Instead, the performance is presented as a reduction in volumetric wear compared to a conventionally sterilized equivalent. This suggests the acceptance criterion was "demonstrate a reduction in volumetric wear" and the studies performed to meet this criterion successfully showed such a reduction.
Here's an analysis of the provided information:
1. Table of Acceptance Criteria and Reported Device Performance
| Acceptance Criterion (Implied) | Reported Device Performance |
|---|---|
| Demonstrates a reduction in volumetric wear compared to conventionally gamma sterilized UHMWPE in a multiaxial hip joint simulator. | 36% reduction in volumetric wear for Duration® Stabilized UHMWPE (System 12®, P4, 32mm ID, 6.1mm bearing thickness, 6 months aged in oxygen) vs. conventionally gamma sterilized equivalent (6 months aged in oxygen). (Tested over 10 million cycles) |
| 40% reduction in volumetric wear for Duration® Stabilized UHMWPE (generic hemispherical cup, 32 mm ID, 8.4 mm bearing thickness) vs. conventionally gamma sterilized equivalent. (Tested over 5 million cycles) | |
| 40% reduction in volumetric wear for Duration® Stabilized UHMWPE (System 12® Neutral Acetabular Insert, P4, 32mm ID, 6.1mm bearing thickness) vs. conventionally gamma sterilized equivalent. (Tested over 5 million cycles) | |
| Demonstrates a reduction in volumetric wear compared to conventionally gamma sterilized UHMWPE after accelerated aging. | 27% reduction in volumetric wear for Duration® Stabilized UHMWPE (generic hemispherical cup, 32mm ID, 8.4mm bearing thickness, 11 days heating in air to simulate 5 years "aging") vs. conventionally gamma sterilized equivalent (with same aging). (Tested over 10 million cycles) |
Note on Acceptance Criteria: The document presents the results as statements of fact rather than explicit "criteria." The FDA's 510(k) clearance process relies on demonstrating "substantial equivalence" to a predicate device. For material claims like reduced wear, demonstrating a quantitatively superior or equivalent performance to a legally marketed predicate (or baseline, in this case, conventionally sterilized UHMWPE) serves as the basis for clearance. The "acceptance" is implicitly tied to these demonstrated reductions.
2. Sample Size Used for the Test Set and Data Provenance
- Sample Size: The document does not explicitly state a "sample size" in terms of number of individual components tested in each condition. It refers to single tests or sets of tests (e.g., "System 12®, size P4, neutral acetabular inserts," "a hemispherical cup of generic design"). Typically, such in vitro wear testing involves a small number of samples (often n=3 or n=5) for each condition, but this detail is not provided.
- Data Provenance: The data is generated from in vitro laboratory testing using multiaxial hip joint simulators. The studies were conducted by Howmedica Inc. and an "independent laboratory" for one of the tests. The document explicitly states: "The results of in vitro tests have not been shown to correlate with clinical wear mechanisms."
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts
Not applicable. This is an in vitro mechanical wear test of a medical device, not a diagnostic or clinical study requiring human experts for ground truth establishment. The "ground truth" here is the measured volumetric wear in a controlled laboratory environment.
4. Adjudication Method for the Test Set
Not applicable. As noted above, this is an in vitro mechanical test, so there is no expert adjudication process. The measurements of volumetric wear are objective and quantifiable by laboratory equipment.
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 not an AI/human-in-the-loop study. It's an in vitro material performance study.
6. If a Standalone (i.e. algorithm only without human-in-the-loop performance) was done
Not applicable. This is explicitly an in vitro mechanical wear test of a physical medical device (UHMWPE acetabular components). It is not an algorithm, AI, or software device.
7. The Type of Ground Truth Used
The ground truth used is objective, quantitatively measured volumetric wear determined by laboratory testing in a hip joint simulator. This is a direct physical measurement, not based on expert consensus, pathology, or outcomes data, as explicitly warned by the statement: "The results of in vitro tests have not been shown to correlate with clinical wear mechanisms."
8. The Sample Size for the Training Set
Not applicable. This is an in vitro performance study for a physical device, not an AI or machine learning model. Therefore, there is no "training set."
9. How the Ground Truth for the Training Set was Established
Not applicable, as there is no training set.
§ 888.3350 Hip joint metal/polymer semi-constrained cemented prosthesis.
(a)
Identification. A hip joint metal/polymer semi-constrained cemented prosthesis is a device intended to be implanted to replace a hip 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 an acetabular resurfacing component made of ultra-high molecular weight polyethylene and is limited to those prostheses intended for use with bone cement (§ 888.3027).(b)
Classification. Class II.