(22 days)
The Freedom® Total Knee System is indicated for the following:
- Severe knee joint pain, loss of mobility, and disability due to: rheumatoid arthritis, osteoarthritis, traumatic arthritis, polyarthritis.
- Correction of functional deformities.
- Post-traumatic loss of knee joint contour, particularly when there is patellofemoral erosion, dysfunction, or prior patellectomy.
- Moderate valgus, varus, or flexion trauma.
- Knee fractures untreatable by other methods.
- Revision surgery where sufficient bone stock and soft tissue integrity are present (For PCK Components and Primary PCK Components only).
The Freedom® Total Knee System – Titanium Tibial Base Plate is intended for cemented and single use only.
The Freedom® Total Knee System is comprised of a femoral component, all-poly tibial component, patellar component, tibial base plate and tibial articular surface. The Freedom® Total Knee System's Femoral Component is offered as different versions such as stemmed PCK design, primary PCK, cruciate retaining, posterior stabilizing. The Freedom® Total Knee System's Tibial Base Plate is offered with stemmed design and without stemmed design. The Freedom® Total Knee System was originally cleared under the 510(k) number K082019. Later on, several modifications were made and were cleared under 510(k)s K091280, K192148, K090411, K182574, K131481, K111785 and K200912 respectively.
The primary purpose of this special 510(k) Device Modification to the Freedom® Metal Backed Tibial Component (K090411) is to notify the FDA of the change in materials used to manufacture the tibial base plate from CoCrMo to Wrought Titanium-6Aluminium-4Vanadium ELI Alloy (Ti6Al4V ELI, ASTM F136-13) as an alternative material option for the tibial base plate.
The Titanium Tibial Base Plate is fabricated from Titanium alloy Ti-6Al-4V ELI, compliant with ASTM F136 and is intended for cemented application to replace the articulating surface of the proximal tibia in a measured resection technique.
The Titanium Tibial Base Plates are available in 8 different sizes (1 to 8) based on Anterior/Posterior (A/P) and Medial/Lateral (M/L) dimensions.
This 510(k) clearance letter pertains to a Class II medical device, specifically the Freedom® Total Knee System - Titanium Tibial Base Plate (K251717). The submission is a special 510(k) Device Modification, indicating that the changes made to the device are well-defined and do not significantly alter the indications for use or raise new questions of safety and effectiveness.
The core change is the material of construction for the tibial base plate, shifting from CoCrMo to Wrought Titanium-6Aluminium-4Vanadium ELI Alloy (Ti-6Al-4V ELI). The design, geometry, surfaces, and locking features remain identical to the previously cleared predicate device (K090411).
Therefore, the acceptance criteria and the study proving the device meets these criteria primarily focus on mechanical performance and biocompatibility related to this material change, rather than extensive clinical efficacy studies or comparative effectiveness studies involving human readers, as would be typical for AI/software devices.
Acceptance Criteria and Reported Device Performance
Given the nature of this submission (a material change for an orthopedic implant with identical design), the acceptance criteria are not explicitly numerical thresholds like sensitivity/specificity, but rather involve demonstrating mechanical equivalence to the predicate device and biocompatibility of the new material.
Here's a table summarizing the implicit acceptance criteria based on standard regulatory requirements for such a device modification, and how the document indicates they were met:
| Acceptance Criteria Category | Specific Criteria (Implicit from Submission Type) | Reported Device Performance (as per 510(k) Summary) |
|---|---|---|
| Mechanical Performance | The Titanium Tibial Base Plate must demonstrate equivalent or superior mechanical integrity and fatigue resistance compared to the predicate device to ensure durability and prevent failure under intended physiological loads. | Met. "The design, geometry, surface features, locking features and dimensional attributes of the Titanium Tibial Base Plate are identical to those of the previously cleared Freedom® Metal Backed Tibial Base Plate (K090411)." |
| "Hence, to evaluate the device function and performance for its intended use, the Freedom® Titanium Tibial Base Plate was subjected to the following mechanical tests:Tibial Tray Fatigue Testing per ASTM F1800Range of Motion & Modular disassembly testing was leveraged from the reference device (K090411) as the subject device uses an identical tibial insert locking mechanism." | ||
| Material Biocompatibility | The new material (Ti-6Al-4V ELI) must be biocompatible and not elicit adverse biological responses (e.g., toxicity, sensitization, irritation) when implanted in the human body. | Met. "Biocompatibility testing is not required for the subject Titanium Tibial Base Plate device, because the material, Ti-6Al-4V ELI Titanium Alloy is compliant with ASTM F136, is a well-established material with a long history of safe use in orthopedic implants." |
| "This material has been used extensively for many years without any major biocompatibility related safety concerns." | ||
| "Additionally, the material has been used in multiple components of Maxx Orthopedics' previously cleared Freedom® Total Knee System…" | ||
| "It also complies with the biocompatibility requirements outlined in 'Class II Special Controls Guidance Document: Knee Joint Patellofemorotibial and Femorotibial Metal/Polymer Porous-Coated Uncemented Prostheses; Guidance for Industry and FDA'". | ||
| "Furthermore, Ti-6Al-4V ELI Titanium Alloy (ASTM F136) has also been used in similar tibial base plate components from other legally marketed devices, intended for same anatomical location and patient contact type, as demonstrated in K220737." | ||
| "A risk-based assessment, following the principles outlined in FDA's 2023 Biocompatibility guidance (Use of ISO 10993-1), confirms that the material change does not introduce new types of patient contact, contact duration, or clinical use conditions that would require additional biocompatibility testing." | ||
| Equivalence in Design/Function | The device design must be substantially equivalent to the predicate, with any minor differences not raising new safety or effectiveness concerns. | Met. "The design, geometry, surface features, locking features and dimensional attributes of the Titanium Tibial Base Plate are identical to those of the previously cleared Freedom® Metal Backed Tibial Base Plate (K090411)." |
| "There are no significant technological differences between the subject and predicate device. The subject device uses a similar design and dimensions, geometry and sizing, and achieves its intended use in an identical manner as the primary predicate and both devices are manufactured using similar subtractive manufacturing techniques." | ||
| Sterilization Method (Minor Change) | If the sterilization method changes, its effectiveness must be validated. | Addressed. "Minor differences in subject device are that it uses different materials of constructions and sterilization method that are addressed via performance testing and similarity to the secondary predicate devices (K241597)." While not explicitly detailed, the mention implies this was covered. |
Study Details (Relevant to Orthopedic Implants, Not AI)
The provided text describes a submission for an orthopedic implant and does not involve an AI/software component, nor does it detail a clinical study with human patients for AI performance evaluation. Therefore, many of the requested points regarding sample sizes for test/training sets, expert readers, ground truth for AI, MRMC studies, etc., are not applicable to this type of device clearance and are consequently not found in the document.
However, based on the information provided, here's what can be inferred/stated:
-
Sample size used for the test set and data provenance:
- Test Set: Not applicable in the context of clinical AI performance data. For mechanical testing (ASTM F1800), standard test methods specify the number of samples required (e.g., minimum of 6 samples for fatigue per ASTM F1800-97), but the exact number used in this specific submission is not reported in the summary.
- Data Provenance: Not applicable for AI performance data. For material and design, the device is manufactured by Maxx Orthopedics Inc. (Norristown, PA, USA) and Meril Healthcare Pvt. Ltd. (Vapi, Gujarat, India).
-
Number of experts used to establish the ground truth for the test set and qualifications of those experts:
- Not applicable as this is a mechanical and material modification, not an AI diagnostic device requiring expert interpretation of images for ground truth.
-
Adjudication method (e.g., 2+1, 3+1, none) for the test set:
- Not applicable for the type of device/study described.
-
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:
- No. This type of study (MRMC, AI assistance) is not relevant or performed for this device. The submission is for a physical orthopedic implant with a material change.
-
If a standalone (i.e. algorithm only without human-in-the-loop performance) was done:
- Not applicable, as there is no algorithm or AI component in this device.
-
The type of ground truth used (expert consensus, pathology, outcomes data, etc.):
- For the mechanical testing, the "ground truth" would be the engineering specifications and performance of the predicate device, alongside adherence to international standards (e.g., ASTM F1800).
- For biocompatibility, the "ground truth" is established long-term clinical use data, compliance with ASTM F136 (Standard Specification for Wrought Titanium-6Aluminum-4Vanadium ELI Alloy for Surgical Implant Applications), and prior FDA clearances of devices using this material.
-
The sample size for the training set:
- Not applicable (no AI training set).
-
How the ground truth for the training set was established:
- Not applicable (no AI training set).
In summary, the FDA clearance for K251717 as a special 510(k) is based on demonstrating that the new Titanium Tibial Base Plate is mechanically equivalent to its predicate and that the new material is biocompatible and has a well-established history of safe use in similar orthopedic applications. The regulatory review focuses on engineering performance criteria and material biocompatibility rather than clinical performance data from patient studies or AI algorithm validation.
§ 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.