(61 days)
Total hip components are indicated for individuals undergoing primary and revision surgery where other treatments or devices have failed in rehabilitating hips damaged as a result of trauma, inflammatory joint disease such as rheumatoid arthritis, or noninflammatory degenerative joint disease (NIDJD) or any of its composite diagnoses such as osteoarthritis; avascular necrosis; traumatic arthritis; slipped capital epiphysis; fused hip; fracture of the pelvis; diastrophic variant; old, remote osteomyelitis with an extended drainage-free period; nonunion; femoral neck fracture and trochanteric fractures of the proximal femur with heads involvement that are unmanageable using other techniques; femoral osteotomy, or Girdlestone resection; fracture dislocation of the hip; and correction of deformity. The Oxinium Femoral Heads are for single use only and can be used as part of cemented or uncemented total hip arthroplasty.
The Oxinium Femoral Heads are designed for use with femoral stems and acetabular components distributed by Smith & Nephew. The Oxinium Femoral Heads are metal alloy devices processed via a proprietary oxidation process.
The provided document is a 510(k) summary for a medical device (Oxinium Femoral Heads). This type of submission focuses on demonstrating substantial equivalence to a predicate device rather than undergoing a full clinical efficacy trial with detailed acceptance criteria and a study design to meet those criteria in the way an AI/ML device might.
Therefore, the information requested in the prompt (acceptance criteria, sample sizes, expert ground truth, MRMC studies, standalone performance, training set details) is not applicable to this type of regulatory submission and the data presented.
Instead, the document focuses on:
- Mechanical and Clinical Data: A general statement about mechanical equivalence to currently used devices and ability to withstand in vivo loading without failure. Details of specific acceptance criteria for these mechanical tests are not provided.
- Wear Claims: These are marketing claims based on in vitro simulator testing. The document explicitly states: "The results of in vitro tests have not been shown to correlate with clinical wear mechanisms or performance." This means these in vitro results are not presented as meeting clinical acceptance criteria in the manner of a human study.
- Substantial Equivalence Information: The core of the 510(k) submission, confirming the device's similarities to existing predicate devices in design, indications, and material composition.
However, I can extract the closest information available, framed as "reported device performance" and the "study" that generated these figures, which are the in vitro wear tests:
1. Table of Acceptance Criteria and Reported Device Performance
| Acceptance Criteria (Implied by wear claims) | Reported Device Performance (from in vitro wear tests) |
|---|---|
| N/A (No explicit acceptance criteria for in vitro wear rates provided in the document for regulatory approval, these are marketing claims.) | Oxinium Femoral Heads vs. CoCr with conventional polyethylene: |
| - 45% reduction in volumetric wear rates against conventional polyethylene (compared to equivalent sized CoCr femoral heads). | |
| - 61% reduction in volumetric wear rates against conventional polyethylene under roughened conditions (compared to equivalent sized CoCr femoral heads). | |
| Oxinium Femoral Heads vs. CoCr with crosslinked polyethylene: | |
| - Show no detectable wear when used with crosslinked polyethylene. | |
| - CoCr Femoral Heads show 15 times more volumetric wear against crosslinked polyethylene as compared to Oxinium Femoral Heads under roughened conditions. | |
| - Oxinium Femoral Heads on crosslinked polyethylene show no detectable wear in traditional or roughened conditions (CoCr head shows measurable increase in wear rate of crosslinked liners when roughened). |
2. Sample size used for the test set and the data provenance
- Sample Size: "Five million cycles per individual test." (This refers to cycles of mechanical testing, not a patient or human-subject sample size). The number of individual tests (e.g., how many Oxinium/CoCr heads were tested) is not specified, but the phrasing "per individual test" implies multiple tests were conducted to generate the results.
- Data Provenance: In vitro laboratory testing using "a multi-axial hip joint simulator," "Reflection Acetabular Liner," and "Hyclone Modified Alpha Serum lubricant." This is laboratory data, not human patient data, and therefore has no country of origin in the clinical sense. It is by definition "retrospective" as the data would have been collected prior to submission.
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts
- Not applicable. The "ground truth" for wear rates was established by mechanical measurements (weight loss of polyethylene liner converted to volume loss) and linear regression analysis, not by human expert assessment.
4. Adjudication method for the test set
- Not applicable. No human adjudication was involved in measuring the in vitro wear rates.
5. If a multi-reader multi-case (MRMC) comparative effectiveness study was done
- No. This type of study is for evaluating human performance, typically in diagnostic imaging, which is not relevant to a mechanical orthopedic implant.
6. If a standalone (i.e., algorithm only without human-in-the-loop performance) was done
- Not applicable. This concept pertains to AI/ML algorithms. The device is a physical orthopedic implant. The "performance" described is purely mechanical/material.
7. The type of ground truth used
- Mechanical Measurement: Wear was determined by weight loss of the polyethylene liner, which was then divided by the density of the polyethylene to determine volume loss. Least squares linear regression of volume loss versus cycle count was used to determine volumetric wear rates. This is a physical, objective measurement from the in vitro test.
8. The sample size for the training set
- Not applicable. This device does not involve a "training set" in the context of AI/ML or statistical modeling from a dataset. The in vitro tests are essentially a test set to characterize the material performance.
9. How the ground truth for the training set was established
- Not applicable, as there is no "training set."
Summary of the K024340 Submission Approach:
The K024340 submission for Oxinium Femoral Heads relies on demonstrating substantial equivalence to existing legally marketed predicate devices primarily through:
- Similarities in design features, overall indications, and material composition.
- In vitro mechanical testing to demonstrate the device's ability to withstand expected in vivo loading (though specific acceptance criteria for this are not detailed in the provided text).
- In vitro wear performance claims, which are explicitly stated not to correlate with clinical wear mechanisms or performance, but rather serve as marketing claims based on laboratory data.
This is a typical approach for a 510(k) for a Class II orthopedic device, where extensive clinical trials with human subjects and associated specific acceptance criteria for efficacy (as would be seen for a PMA or an AI/ML device) are generally not required if substantial equivalence can be demonstrated.
§ 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.