(144 days)
The general indications associated with the use of Patellofemoral Joint Prosthesis in patellofemoral arthroplasty include:
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- Patients with osteoarthritis in the distal femur and patella.
- Patients with a history of patellar dislocation or patellar 2. fracture.
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- Those patients with failed previous surgery (arthroscopy, tibial tubercle elevation, lateral release, etc.) where pain, deformity or dysfunction persists.
The design of the Patellofemoral Joint Prosthesis closely replicates the anatomic features of the patellar groove on a femur. In addition, the design of the highly polished concave gliding anterior surface of the Patellofemoral Joint Prosthesis is identical to the proximal anterior surface of the articulating geometry of the Natural Knee II System's femoral component which has been determined substantially equivalent by the FDA via 510(k) K936159. The highly polished concave gliding surface of the Patellofemoral Joint Prosthesis complements the design of the articulating geometry of the IOI's patella components for optimal patellar tracking.
The posterior surface of the Patellofemoral Joint Prosthesis employs two fixation pegs for enhanced stability of the prosthesis when cemented into the femur. In addition, the posterior surface of the Patellofemoral Joint Prosthesis employs a grit blasted roughened surface to facilitate interdigitation with bone cement. The roughness of the grit blasted surface ranges from 175 - 225 uinch.
The Patellofemoral Joint Prosthesis is an asymmetrically designed component and, therefore, is available in both left and right configurations.
This document is a 510(k) premarket notification for a medical device submitted in 1996. It outlines the device's characteristics and compares them to predicate devices to establish substantial equivalence.
1. Table of Acceptance Criteria and Reported Device Performance
This 510(k) notice explicitly states that the device's safety and effectiveness are established through substantial equivalence to predicate devices, rather than through specific performance metrics and acceptance criteria from a clinical study. The "performance" here refers to the device's features and materials matching or being similar to those of previously approved devices.
| Feature / Characteristic | Acceptance Criteria (Implicit for Substantial Equivalence) | Reported Device Performance (Patellofemoral Joint Prosthesis) |
|---|---|---|
| Application | Cemented | Cemented |
| Material | Cast CoCr Alloy / Stainless Steel | Cast CoCr Alloy |
| Concave design | Yes | Yes |
| Fixation pegs | Varied (e.g., One, Three) | Two |
| Asymmetric design | Varied (Yes/No) | Yes |
| Design replication | Closely replicates anatomic features of patellar groove | Closely replicates anatomic features of patellar groove; identical to Natural Knee II System's femoral component's articulating geometry |
| Posterior surface | Roughened for cement interdigitation | Grit blasted roughened surface (175 - 225 uinch) for cement interdigitation; two fixation pegs |
Study Proving Acceptance Criteria:
The study proving the device meets the "acceptance criteria" (i.e., substantial equivalence) is the 510(k) Premarket Notification itself, which acts as a regulatory submission. It does not describe a clinical performance study with specific acceptance criteria that were met with statistical significance. Instead, it argues that the device is "substantially equivalent" to legally marketed predicate devices based on design, materials, and intended use.
2. Sample Size Used for the Test Set and Data Provenance:
This document does not describe a clinical test set with human subjects. The "test" is a comparison of the device's specifications and design features against those of predicate devices. There is no sample size of patients or data provenance in the context of a clinical study.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts:
Not applicable. The "ground truth" for this 510(k) submission is the pre-existing regulatory approval and market presence of the predicate devices. There were no experts used to establish ground truth for a clinical test set in this context.
4. Adjudication Method for the Test Set:
Not applicable. There was no clinical test set requiring adjudication.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was done:
No, an MRMC comparative effectiveness study was not done. This submission focuses on engineering and design comparisons for substantial equivalence, not clinical effectiveness studies comparing human readers or AI.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) was done:
Not applicable. This is a physical medical device (prosthesis), not an algorithm or AI system.
7. The Type of Ground Truth Used:
The "ground truth" used in this context is the existence and regulatory approval of the predicate devices. The argument for the new device's safety and effectiveness is based on its similarity to these already-approved devices, assuming their safety and effectiveness are established. There is no pathology, expert consensus (in the context of clinical outcomes), or outcomes data presented for the new device itself to establish ground truth.
8. The Sample Size for the Training Set:
Not applicable. This is not an AI/ML device requiring a training set. The "training" for this device's development would be engineering design principles and knowledge of existing prostheses.
9. How the Ground Truth for the Training Set was Established:
Not applicable as there is no training set mentioned for this type of device.
§ 888.3540 Knee joint patellofemoral polymer/metal semi-constrained cemented prosthesis.
(a)
Identification. A knee joint patellofemoral polymer/metal semi-constrained cemented prosthesis is a two-part device intended to be implanted to replace part of a knee joint in the treatment of primary patellofemoral arthritis or chondromalacia. 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 a component made of alloys, such as cobalt-chromium-molybdenum or austenitic steel, for resurfacing the intercondylar groove (femoral sulcus) on the anterior aspect of the distal femur, and a patellar component made of ultra-high molecular weight polyethylene. This generic type of device is limited to those devices intended for use with bone cement (§ 888.3027). The patellar component is designed to be implanted only with its femoral component.(b)
Classification. Class II. The special controls for this device are:(1) FDA's:
(i) “Use of International Standard ISO 10993 ‘Biological Evaluation of Medical Devices—Part I: Evaluation and Testing,’ ”
(ii) “510(k) Sterility Review Guidance of 2/12/90 (K90-1),”
(iii) “Guidance Document for Testing Orthopedic Implants with Modified Metallic Surfaces Apposing Bone or Bone Cement,”
(iv) “Guidance Document for the Preparation of Premarket Notification (510(k)) Applications for Orthopedic Devices,” and
(v) “Guidance Document for Testing Non-articulating, ‘Mechanically Locked’ Modular Implant Components,” and
(2) International Organization for Standardization's (ISO):
(i) ISO 5832-3:1996 “Implants for Surgery—Metallic Materials—Part 3: Wrought Titanium 6-Aluminum 4-Vandium Alloy,”
(ii) ISO 5832-4:1996 “Implants for Surgery—Metallic Materials—Part 4: Cobalt-Chromium-Molybdenum Casting Alloy,”
(iii) ISO 5832-12:1996 “Implants for Surgery—Metallic Materials—Part 12: Wrought Cobalt-Chromium-Molybdenum Alloy,”
(iv) ISO 5833:1992 “Implants for Surgery—Acrylic Resin Cements,”
(v) ISO 5834-2:1998 “Implants for Surgery—Ultra-high Molecular Weight Polyethylene—Part 2: Moulded Forms,”
(vi) ISO 6018:1987 “Orthopaedic Implants—General Requirements for Marking, Packaging, and Labeling,”
(vii) ISO 7207-2:1998 “Implants for Surgery—Components for Partial and Total Knee Joint Prostheses—Part 2: Articulating Surfaces Made of Metal, Ceramic and Plastic Materials,” and
(viii) ISO 9001:1994 “Quality Systems—Model for Quality Assurance in Design/Development, Production, Installation, and Servicing,” and
(3) American Society for Testing and Materials':
(i) F 75-92 “Specification for Cast Cobalt-28 Chromium-6 Molybdenum Alloy for Surgical Implant Material,”
(ii) F 648-98 “Specification for Ultra-High-Molecular-Weight Polyethylene Powder and Fabricated Form for Surgical Implants,”
(iii) F 799-96 “Specification for Cobalt-28 Chromium-6 Molybdenum Alloy Forgings for Surgical Implants,”
(iv) F 1044-95 “Test Method for Shear Testing of Porous Metal Coatings,”
(v) F 1108-97 “Titanium-6 Aluminum-4 Vanadium Alloy Castings for Surgical Implants,”
(vi) F 1147-95 “Test Method for Tension Testing of Porous Metal Coatings,”
(vii) F 1537-94 “Specification for Wrought Cobalt-28 Chromium-6 Molybdenum Alloy for Surgical Implants,” and
(viii) F 1672-95 “Specification for Resurfacing Patellar Prosthesis.”