(280 days)
The intended use of this additional style of System 12® acetabular inserts is identical to that of previously released System 12® inserts: they are intended to be used with Osteolock/Vitalock acetabular shells in primary or revision total hip arthroplasty.
The purpose of this submission is to describe an additional style of System 12® acetabular Inserts which are stabilized/sterilized using a process called Duration® II Stabilization. The purpose of the Duration® If process is to crosslink all of the free radicals found in the UHMWPE rod stock by exposure to gamma radiation followed by a stabilization process in a heated oven. During this radiation/stabilization period, the UHMWPE is exposed to a very low oxygen concentration. The stabilized rod stock is then machined to its final configuration. The acetabular insert is packaged in air, and terminally sterilized by the ethylene oxide sterilization process. The System 12® Acetabular Inserts produced by this method conform to the requirements for Ultra High Molecular Weight Polyethylene specified in ASTM Specification F-648, and the FDA guidance document on UHMWPE used in Bearing Surfaces for Orthopedic Devices.
These System 12® inserts are identical in design to the previously cleared System 12® inserts: they are available in a range of outer diameter sizes to mate with the respective acetabular shell, and 22.0, 22.2, 26, 28, and 32mm inner diameters to mate with Howmedica femoral heads. These inserts are available in a neutral, 10°, and 15° hooded design. The locking mechanism of this style of acetabular insert is identical to the previously released System 12® acetabular inserts.
The manufacturer, Howmedica, sought to introduce an additional style of System 12® acetabular inserts, the Duration® II, which are stabilized/sterilized using a process involving gamma radiation, heated oven stabilization, and ethylene oxide sterilization. The main purpose was to demonstrate substantial equivalence to previously cleared System 12® acetabular inserts.
Here's an analysis of the provided information regarding acceptance criteria and the supporting study:
1. Table of Acceptance Criteria and Reported Device Performance
| Acceptance Criteria / Marketing Claim | Reported Device Performance |
|---|---|
| Material Properties: | |
| 1. Duration® II products meet all ASTM F 648 specified standards. | Met: The summary explicitly states, "The acetabular insert is packaged in air, and terminally sterilized by the ethylene oxide sterilization process. The System 12® Acetabular Inserts produced by this method conform to the requirements for Ultra High Molecular Weight Polyethylene specified in ASTM Specification F-648." |
| 2. Duration® II products have no detectable oxidation as measured by FTIR up to 30 days of accelerated aging at 80°C in air. | Met: The summary states, "Duration® II products have no detectable oxidation as measured by FTIR up to 30 days of accelerated aging at 80° C in air." This is a direct claim made by the manufacturer as a result of their testing. |
| 3. Duration® II products have a higher gel content (cross-linking) than air irradiated UHMWPE measured in accordance with modified ASTM D2765-90 standard. | Met: The summary states, "Duration® II products have a higher gel content (cross-linking) than air irradiated UHMWPE measured in accordance with modified ASTM D2765-90 standard." This is a direct claim made by the manufacturer as a result of their testing. |
| 4. Duration® II has a lower tensile modulus than air irradiated UHMWPE. This lower stiffness has demonstrated an increase in contact area and a decrease in contact stress. | Met: The summary states, "Duration® II has a lower tensile modulus than air irradiated UHMWPE. This lower stiffness has demonstrated an increase in contact area and a decrease in contact stress." This is a direct claim made by the manufacturer as a result of their testing. |
| 5. No free radicals are detected in the Duration® II material when analyzed by the ESR technique of the final product. | Met: The summary states, "No free radicals are detected in the Duration® II material when analyzed by the ESR technique of the final product." This is a direct claim made by the manufacturer as a result of their testing. |
| Wear Performance: | |
| 6. Duration® II has a lower wear rate, as measured by hip wear simulator than air irradiated UHMWPE. | Met: The summary reports significantly lower wear. "Duration® II has a lower wear rate, as measured by hip wear simulator than air irradiated UHMWPE (an average total wear of 198.60 ± 31.9 mm³ instead of 310 ± 40.8 mm³)." |
Details of the Study Proving Device Meets Acceptance Criteria:
The provided document describes a bench testing and material characterization study to support the substantial equivalence of the Duration® II Acetabular Inserts.
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Sample Size Used for the Test Set and Data Provenance:
- Test Set Sample Size: Not explicitly stated for each specific test (e.g., number of samples for FTIR, ESR, tensile modulus). However, for the hip wear simulator, multiple samples would have been run to generate the reported average and standard deviation (198.60 ± 31.9 mm³ and 310 ± 40.8 mm³). The "an average total wear" suggests multiple iterations, but the exact number of tested inserts is not specified.
- Data Provenance: The study was conducted by Howmedica, implying retrospective, in-house laboratory testing within the United States (the contact address is Rutherford, NJ). It is not clinical data.
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Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts:
- Not applicable. This was a laboratory-based material science and mechanical performance study, not a clinical study requiring expert ground truth for diagnostic accuracy. The "ground truth" here is the physical measurement of material properties and wear rates using established scientific methods and standards.
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Adjudication Method for the Test Set:
- Not applicable. As a laboratory study, results are based on instrumental measurements and adherence to specified test protocols (e.g., ASTM standards). There is no "adjudication" in the sense of reconciling human expert opinions.
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Multi Reader Multi Case (MRMC) Comparative Effectiveness Study:
- No, an MRMC comparative effectiveness study was not done. This device is a component of a medical implant, and the study focused on material and mechanical performance, not a diagnostic or treatment effectiveness study requiring human reader assessment.
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Standalone Performance (Algorithm Only without Human-in-the-Loop Performance):
- Yes, the described study assesses the "standalone" performance of the Duration® II material and its components in a laboratory setting. This means the device's inherent properties and performance (wear rate, strength, cross-linking, oxidation) were evaluated directly, without human interaction influencing the measurement results or interpretation in a real-world clinical scenario. The hip wear simulator, for example, tests the device's mechanical wear performance independent of a human's input or interpretation.
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Type of Ground Truth Used:
- The "ground truth" used for this "device" (material) is based on standardized physical and chemical measurements and comparative laboratory testing against a predicate device or control. This includes:
- Material properties: Adherence to ASTM F-648, FTIR for oxidation, ESR for free radicals, modified ASTM D2765-90 for gel content, and tensile modulus measurements.
- Mechanical performance: Hip wear simulator testing provides quantitative wear rate data.
- The "ground truth" used for this "device" (material) is based on standardized physical and chemical measurements and comparative laboratory testing against a predicate device or control. This includes:
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Sample Size for the Training Set:
- Not applicable. There is no explicit "training set" in this context. The study describes the characterization and testing of the final product material. While manufacturing process parameters are optimized, the document does not detail a separate "training" phase for the material itself in the way an AI algorithm has a training set.
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How the Ground Truth for the Training Set Was Established:
- Not applicable, as there was no "training set" in the conventional sense of machine learning. The "ground truth" for the material's properties (e.g., meeting ASTM F-648 standards) is established by the specifications defined by the standard itself and verified through appropriate analytical and mechanical testing methods.
§ 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.