(88 days)
- This device is indicated for:
- Moderate to severe knee instability
- Significant bone loss and/or ligament deficiencies caused by neoplasms, trauma, rheumatoid arthritis, osteoarthritis, traumatic arthritis, polyarthritis, collagen disorders, and/or avascular necrosis of the femoral condyle
- Valgus, varus or flexion deformities
- The salvage of previously failed surgical attempts
- A total femoral replacement construct consisting of MOST Options proximal femoral, Segmental System segments and Segmental System distal femoral components may be used without cement.
- Fluted stem extensions require the use of either a smooth or Trabecular Metal stem collar, which must be cemented to the stem. Following cementing to the stem extension, the smooth collar and the remainder of the stem must also be cemented against the bone.
- The Trabecular Metal collar may be used cemented or uncemented against the bone as long as the remainder of the stem extension is cemented.
- All other constructs are for cemented use only.
The Zimmer® Segmental System is a fully constrained cemented knee prosthesis intended to replace the distal femur and/or total knee in cases that require extensive resection and restoration. The Segmental Knee System provides for cross compatibility between selected components from the MOST System and the NexGen Rotating Hinge Knee Systems. When used with MOST System proximal femur and NexGen Rotating Hinge Knee tibial baseplates, a total mid-calf to hip replacement can be achieved. The distal femoral components are designed to be compatible with all current NexGen patella components. The Segmental System is a modular system comprised of fluted stem extensions, segments, articular surfaces and distal femoral components. The prosthesis is designed to be used with NexGen patellar and tibial components as well as the MOST System proximal femoral component.
Here's an analysis of the provided text regarding the Zimmer® Segmental System, focusing on acceptance criteria and the study proving it:
It's important to note that the provided documentation is a 510(k) premarket notification summary for a medical device. This type of submission relies heavily on demonstrating substantial equivalence to a legally marketed predicate device, rather than requiring extensive de novo clinical trials with predefined acceptance criteria for novel device performance.
Acceptance Criteria and Reported Device Performance
The concept of "acceptance criteria" for a 510(k) typically refers to demonstrating that the new device is as safe and effective as its predicate. For the Zimmer® Segmental System, the core acceptance criterion is substantial equivalence to the predicate devices. The performance data presented focuses on justifying this equivalence.
| Acceptance Criterion (Implied for 510(k) Substantial Equivalence) | Reported Device Performance (as stated in the document) |
|---|---|
| Device is safe and effective as the predicate device | Non-Clinical Performance: "The results of non-clinical (lab) performance testing demonstrate that the device is safe and effective." |
| Identical intended use as the predicate device | "This device also has the same intended use as predicate devices." |
| Similar technological characteristics to the predicate device | "The Segmental System is a modular system comprised of fluted stem extensions, segments, articular surfaces and distal femoral components. The prosthesis is designed to be used with NexGen patellar and tibial components as well as the MOST System proximal femoral component." |
| "The device shares a similar fixation method as the predicate devices." | |
| "This device is packaged, manufactured and sterilized using the same materials and processes as the predicate devices." | |
| (Note: A specific difference in fixation with the Trabecular Metal collar is acknowledged but not presented as a non-conformance, implying the non-clinical testing addressed it.) |
Study Details
The document states: "Clinical data were not needed for this device." This is a critical piece of information. Therefore, many of the typical questions for a clinical study involving AI or novel technology are not applicable here. The "study" proving the device meets acceptance criteria is primarily non-clinical (lab) performance testing.
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Sample size used for the test set and the data provenance:
- Test Set Sample Size: Not specified. The document only mentions "non-clinical (lab) performance testing." Details on the number of components, configurations, or test repetitions are not provided in this summary.
- Data Provenance: Not specified, but implied to be from Zimmer, Inc.'s internal or contracted lab testing.
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Number of experts used to establish the ground truth for the test set and the qualifications of those experts (e.g., radiologist with 10 years of experience):
- Not Applicable. Since no clinical data or human interpretation was used to establish ground truth for a test set, there were no experts involved in this capacity. The "ground truth" for non-clinical testing would be measured physical properties (e.g., strength, fatigue life) against established engineering standards or predicate device performance.
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Adjudication method (e.g., 2+1, 3+1, none) for the test set:
- Not Applicable. No human adjudication of a test set (e.g., images for diagnosis) was performed as clinical data was not used.
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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 device, and no MRMC study or AI assistance was involved.
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If a standalone (i.e. algorithm only without human-in-the loop performance) was done:
- Not Applicable. This is a physical knee prosthesis, not an algorithm.
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The type of ground truth used (expert consensus, pathology, outcomes data, etc.):
- For the non-clinical testing, the "ground truth" would be engineering specifications, material properties, and mechanical performance standards relevant to orthopedic implants. Comparisons would likely have been made to the performance characteristics of the predicate devices under similar testing conditions.
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The sample size for the training set:
- Not Applicable. This is not an AI/machine learning device, so there is no training set in that context. If "training set" refers to design and development iterations, that information is not provided.
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How the ground truth for the training set was established:
- Not Applicable. As there is no training set in the AI/ML sense, this question does not apply.
Summary of the "Study" Proving Acceptance Criteria:
The Zimmer® Segmental System received 510(k) clearance based on non-clinical (lab) performance testing which demonstrated the device is "safe and effective." This testing would have focused on mechanical properties, material integrity, and other engineering characteristics to show that the new device performs comparably to its predicate devices, thereby establishing substantial equivalence. No clinical studies or human-in-the-loop performance evaluations were deemed necessary for this particular submission.
§ 888.3510 Knee joint femorotibial metal/polymer constrained cemented prosthesis.
(a)
Identification. A knee joint femorotibial metal/polymer constrained cemented prosthesis is a device intended to be implanted to replace part of a knee joint. The device limits translation or rotation in one or more planes and has components that are linked together or affined. This generic type of device includes prostheses composed of a ball-and-socket joint located between a stemmed femoral and a stemmed tibial component and a runner and track joint between each pair of femoral and tibial condyles. The ball-and-socket joint is composed of a ball at the head of a column rising from the stemmed tibial component. The ball, the column, the tibial plateau, and the stem for fixation of the tibial component are made of an alloy, such as cobalt-chromium-molybdenum. The ball of the tibial component is held within the socket of the femoral component by the femoral component's flat outer surface. The flat outer surface of the tibial component abuts both a reciprocal flat surface within the cavity of the femoral component and flanges on the femoral component designed to prevent distal displacement. The stem of the femoral component is made of an alloy, such as cobalt-chromium-molybdenum, but the socket of the component is made of ultra-high molecular weight polyethylene. The femoral component has metallic runners which align with the ultra-high molecular weight polyethylene tracks that press-fit into the metallic tibial component. The generic class also includes devices whose upper and lower components are linked with a solid bolt passing through a journal bearing of greater radius, permitting some rotation in the transverse plane, a minimal arc of abduction/adduction. This generic type of device is limited to those prostheses intended for use with bone cement (§ 888.3027).(b)
Classification. Class II.