(180 days)
The Trilogy® Acetabular System is indicated for either cemented or noncemented use in skeletally mature individuals undergoing surgery for rehabilitating hips damaged as a result of noninflammatory degenerative joint disease (NIDJD) or its composite diagnoses of osteoarthritis, avascular necrosis, traumatic arthritis, slipped capital epiphysis, fused hip, fracture of the pelvis, and diastrophic variant.
The Trilogy Acetabular System Longevity Crosslinked Polyethylene Liners are modular, acetabular components of the same design, geometry, material, and intended use which was previously cleared in premarket notification K934765, This premarket notification contains wear test data of electron beam irradiated UHMWPE components to substantiate claims of improved wear properties due to the change in processing of the devices.
Here's an analysis of the provided text regarding the acceptance criteria and the study proving the device meets them:
1. Table of Acceptance Criteria and Reported Device Performance
The FDA clearance outlines wear reduction as the primary performance claim, specifically for the Trilogy® Acetabular System Longevity® Crosslinked Polyethylene Liners.
| Acceptance Criteria | Reported Device Performance |
|---|---|
| Wear Reduction | Average 89% gravimetric wear reduction compared to conventionally gamma sterilized and aged cups. |
| Residual Free Radicals | Undetectable, below the experimental detection limit of 10¹³ spins/gram. |
2. Sample Size Used for the Test Set and Data Provenance
The provided document describes in-vitro testing, not studies involving human subjects or clinical data in the traditional sense. Therefore, the concepts of "test set sample size" and "data provenance" (country of origin, retrospective/prospective) as they apply to clinical studies are not directly applicable here.
- Test Set Description: The "test sets" for the wear and residual free radical evaluations consisted of:
- Wear Testing: Neutral liners of specific dimensions (32 mm ID/48 mm OD, 5.3 mm thickness, and 22 mm ID/36 mm OD, 4.3 mm thickness) made from compression-molded, calcium stearate-free, highly crosslinked, thermal-stabilized, and gas plasma sterilized UHMWPE. Both non-aged (final product after sterilization) and accelerated-aged conditions were tested. The accelerated aging involved 73 psi of oxygen at 70°C for two weeks.
- Residual Free Radical Testing: Zimmer highly crosslinked, thermally stabilized UHMWPE in both accelerated-aged and non-aged conditions.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications
Not applicable. This document details material testing (in-vitro wear and free radical analysis), not studies requiring human expert adjudication for ground truth. The "ground truth" here is the direct experimental measurement of material properties (gravimetric wear and free radical content).
4. Adjudication Method for the Test Set
Not applicable, as this was an in-vitro material testing study, not a study requiring human adjudication for interpretation of results.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done, and the Effect Size
No, a Multi-Reader Multi-Case (MRMC) comparative effectiveness study was not done. This is an a-clinical submission focused on material properties and wear performance, not a study involving human readers or clinical outcomes that would necessitate an MRMC design.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done
Yes, in a sense. The studies described are standalone in that they involve the testing of the device material itself, independent of human interaction or interpretation beyond the setup and analysis of the experimental equipment. The "algorithm" in this context is the physical and chemical properties of the material and its performance under specific simulated conditions.
7. The Type of Ground Truth Used
The ground truth used in these studies is:
- Direct Experimental Measurement:
- Gravimetric Wear: Measured directly from the simulated hip environment.
- Residual Free Radicals: Measured directly using Electron Spin Resonance (ESR) spectroscopy.
8. The Sample Size for the Training Set
Not applicable. This submission describes pre-market testing of a medical device material, not a machine learning model that would require a "training set." The material itself is the "tested entity."
9. How the Ground Truth for the Training Set Was Established
Not applicable, as there is no "training set" in the context of a machine learning model. The wear data and free radical content are direct experimental results used to demonstrate the performance of the crosslinked polyethylene material.
§ 888.3358 Hip joint metal/polymer/metal semi-constrained porous-coated uncemented prosthesis.
(a)
Identification. A hip joint metal/polymer/metal semi-constrained porous-coated uncemented 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 has a femoral component made of a cobalt-chromium-molybdenum (Co-Cr-Mo) alloy or a titanium-aluminum-vanadium (Ti-6Al-4V) alloy and an acetabular component composed of an ultra-high molecular weight polyethylene articulating bearing surface fixed in a metal shell made of Co-Cr-Mo or Ti-6Al-4V. The femoral stem and acetabular shell have a porous coating made of, in the case of Co-Cr-Mo substrates, beads of the same alloy, and in the case of Ti-6Al-4V substrates, fibers of commercially pure titanium or Ti-6Al-4V alloy. The porous coating has a volume porosity between 30 and 70 percent, an average pore size between 100 and 1,000 microns, interconnecting porosity, and a porous coating thickness between 500 and 1,500 microns. The generic type of device has a design to achieve biological fixation to bone without the use of bone cement.(b)
Classification. Class II.