(57 days)
This device is indicated for patients with severe knee pain and disability due to:
- Rheumatoid arthritis, osteoarthritis, traumatic arthritis, polyarthritis.
- Collagen disorders, and/or avascular necrosis of the femoral condyle.
- Post-traumatic loss of joint configuration, particularly when there is patellofemoral erosion, dysfunction or prior patellectomy.
- Moderate valgus, varus, or flexion deformities.
- The salvage of previously failed surgical attempts or for a knee in which satisfactory stability in flexion cannot be obtained at the time of surgery.
This device is intended to be used with cemented knee constructs.
The Persona 14 x+30mm Tapered Stem Extension is intended for implantation for total knee arthroplasty (TKA) when supplemental tibial baseplate support is needed. Extending into the intramedullary canal from the base of the Persona Cemented Stemmed Tibia Baseplate, the Persona 14 x+30mm Stem Extension provides supplemental support and shields the fixation interfaces from excessive stress by resisting bending and torsional moments. The subject device is intended to be used with cement knee constructs.
Here's an analysis of the provided text regarding the Zimmer® Persona The Personalized Knee System 14 x+30mm Tapered Stem Extension, focusing on acceptance criteria and the supporting study:
The provided document (K133737) is a 510(k) summary for a medical device. It focuses on demonstrating substantial equivalence to predicate devices through non-clinical testing. It's important to note that this device is a physical implant (a knee system component), not an AI/software device. Therefore, many of the requested fields related to AI study design (like MRMC, human readers, ground truth for training data, etc.) are not applicable in this context.
1. Table of Acceptance Criteria and Reported Device Performance
The document does not explicitly state quantitative "acceptance criteria" in a table format with pass/fail thresholds. Instead, it describes "performance characteristics" and the "Test Results" demonstrating that the device meets these characteristics. The context implies that the acceptable outcome is for the device to demonstrate sufficient strength or to be assessed for risk in comparison to existing devices, aligning with established FDA guidance for orthopedic implants.
| Property or Characteristic | Acceptance Criteria (Implied) | Reported Device Performance |
|---|---|---|
| Fatigue Test of the Persona Tibia Keel and Stem Extension | Demonstrate sufficient fatigue strength to survive expected worst-case loading conditions, likely in line with predicate devices and FDA guidance. | "Demonstrated that the Persona tibia keel and stem extension taper junction has sufficient fatigue strength to survive expected worst case loading conditions." |
| Static Axial and Torsional Strength of the Persona Stem Extension Taper | Demonstrate adequate static axial and torsional strength, likely in line with predicate devices and FDA guidance for modular implant components. | "Demonstrated the static axial and torsional strength of the Persona stem extension taper mechanism." |
| The Risk of Cortex Perforation for Persona Tibial Components with +30MM Stem | Assess and quantify the potential risk of cortex perforation, ideally demonstrating it is comparable to or acceptable relative to predicate devices like the NexGen tibial implant when implanted similarly. (No explicit "acceptance" is stated, but rather an assessment). | "Assessed the potential risk of cortex perforation of the Persona stemmed tibial implant with the 14 x +30mm stem extension compared to the NexGen tibial implant when implanted in the same manner." (The summary does not provide the quantitative outcome of this assessment, only that it was conducted.) |
2. Sample Size Used for the Test Set and Data Provenance
- Sample Size: The document does not specify the exact sample size (e.g., number of test specimens) for each bench test. For mechanical tests like fatigue and strength, multiple samples are typically tested, but no numbers are provided here.
- Data Provenance: The data is non-clinical bench testing, meaning it was generated in a laboratory setting, not from human or animal subjects. The location of the testing is not explicitly stated but would typically be in the sponsor's (Zimmer, Inc.) labs or a qualified contract testing facility. This is retrospective in the sense that the testing was performed and then reported, but it is not clinical data.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of those Experts
This question is not applicable as the study involves mechanical bench testing of an orthopedic implant component, not an AI or diagnostic device requiring expert interpretation for ground truth. The "ground truth" for these tests is defined by engineering principles and measurement of physical properties.
4. Adjudication Method for the Test Set
This question is not applicable. Mechanical tests rely on objective measurements from standardized equipment rather than subjective human interpretation requiring adjudication.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was done
This question is not applicable. This is a submission for a physical orthopedic implant component, not a diagnostic device or AI system that would involve human readers. Clinical data and conclusions "were not needed for this device."
6. If a Standalone (i.e. algorithm only without human-in-the loop performance) was done
This question is not applicable as the device is a physical knee implant component, not an algorithm.
7. The Type of Ground Truth Used
The "ground truth" for this non-clinical study is defined by:
- Mechanical Properties: Measured physical characteristics such as fatigue life, axial strength, torsional strength.
- Engineering Standards and FDA Guidance: Compliance with relevant ASTM (American Society for Testing and Materials) or ISO (International Organization for Standardization) standards (implied by the FDA guidance documents cited) that define appropriate testing methodologies and performance expectations for such devices.
- Comparison to Predicate Devices: Performance relative to legally marketed predicate devices, demonstrating similarity in performance characteristics.
8. The Sample Size for the Training Set
This question is not applicable. There is no "training set" as this is a physical medical device and not an AI or machine learning model.
9. How the Ground Truth for the Training Set was Established
This question is not applicable for the same reasons as #8.
§ 888.3560 Knee joint patellofemorotibial polymer/metal/polymer semi-constrained cemented prosthesis.
(a)
Identification. A knee joint patellofemorotibial polymer/metal/polymer semi-constrained cemented prosthesis is a device intended to be implanted to replace a knee 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 a tibial component or components and a retropatellar resurfacing component made of ultra-high molecular weight polyethylene. This generic type of device is limited to those prostheses intended for use with bone cement (§ 888.3027).(b)
Classification. Class II.