(85 days)
The Imaging Therapeutics, Inc. Knee Interpositional Mini-Repair System (KIMRS) is intended for use in the osteoarthritic knee, where substantial amounts of articular cartilage have degenerated as a result of the disease, and in patients who are candidates for total and/or uni-compartmental arthroplasty procedures. The implant is indicated for the un-cemented treatment of the medial and/or lateral tibial articulating surfaces of the following:
Moderate degeneration of the medial or lateral compartment of the knee (grade II-IV chondromalacia) and minimal degeneration (grade I-II chondromalacia, no loss of joint space) in the patellofemoral compartments.
The Imaging Therapeutics, Inc. Knee Interpositional Mini-Repair System is intended to be implanted in the knee as a non-fixated, intra-articular support with minimal to no movement of the device after implantation.
Imaging Therapeutics, Inc. Knee Interpositional Mini-Repair System is a minimally invasive, bone preserving, approach for the treatment of the osteoarthritic knee. Developed from patient Magnetic Resonance (MR) scans a patient specific implant is designed.
The treatment allows for the placement of an un-cemented metallic device designed from the patient's natural cartilage and meniscal geometry that is implanted into the joint space either in the medial or lateral compartment above the affected tibial plateau. The femur then articulates against the smooth implant surface. The implant is manufactured from cobalt chromium molybdenum alloy.
The provided document describes a 510(k) premarket notification for the "Knee Interpositional Mini-Repair System (KIMRS)" by Imaging Therapeutics, Inc. The primary purpose of this submission is to demonstrate substantial equivalence to predicate devices, rather than to prove that the device meets specific acceptance criteria through a clinical study. The study conducted is a bench test on cadaveric knees comparing the mechanical movement of the KIMRS with a predicate device, the Centerpulse Unispacer.
Here's the breakdown of the acceptance criteria and study information based on the provided text:
1. Table of Acceptance Criteria and Reported Device Performance
| Acceptance Criteria (Implied) | Reported Device Performance (KIMRS) | Predicate Device Performance (Unispacer) |
|---|---|---|
| Cadaver Knee 1 | ||
| Anterior Excursion (Lateral view) should be comparable to predicate | 4.5 mm | 3.1 mm |
| Posterior Excursion (Lateral view) should be comparable to predicate | 4.8 mm | 6.0 mm |
| Medial-Lateral Excursion (Anterior-Posterior View) should be comparable to predicate and ideally minimal | 1.2 mm (stated "no significant translation medially" for KIMRS) | 2.8 mm (stated "considerably more movement medially" for Unispacer) |
| Cadaver Knee 2 | ||
| Anterior Excursion (Lateral view) should be comparable to predicate | 3.6 mm | 4.0 mm |
| Posterior Excursion (Lateral view) should be comparable to predicate | 2.9 mm | 4.5 mm |
| Medial-Lateral Excursion (Anterior-Posterior View) should be comparable to predicate and ideally minimal | 0.3 mm | 1.9 mm |
Note regarding Acceptance Criteria: The document does not explicitly state numerical acceptance criteria. Instead, it relies on demonstrating comparability to a legally marketed predicate device (Centerpulse Unispacer). The "acceptance criteria" are thus implicitly that the KIMRS performs similarly or better than the predicate device in terms of movement within the cadaveric knee. The text concludes that "The ImaTx Knee Interpositional Mini-Repair System performed comparably to the Unispacer implant."
2. Sample Size Used for the Test Set and Data Provenance
- Sample Size for Test Set: Two cadaveric knee specimens.
- Data Provenance: Retrospective (cadaveric specimens), location not specified.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of those Experts
- This study did not involve experts establishing ground truth in the traditional sense of clinical assessment. It was a biomechanical test comparing implant movement. No information is provided regarding human experts for this specific comparative testing.
4. Adjudication Method for the Test Set
- Not applicable. This was a biomechanical measurement study, not an assessment requiring adjudication of human observations or diagnoses.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done
- No, a Multi-Reader Multi-Case (MRMC) comparative effectiveness study was not done. This study focuses on the mechanical performance of the device in cadavers, not on human reader performance.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done
- Not applicable. This device is a physical knee implant, not an algorithm or AI system.
7. The Type of Ground Truth Used
- The "ground truth" in this context refers to the direct physical measurement of implant excursion within the cadaveric knee using fluoroscopy. This is akin to direct measurement/physical observation rather than expert consensus, pathology, or outcomes data. The predicate device's performance serves as a comparative benchmark.
8. The Sample Size for the Training Set
- Not applicable. This is a physical medical device, not an AI or algorithm-based system that requires a "training set."
9. How the Ground Truth for the Training Set Was Established
- Not applicable (as above).
§ 888.3590 Knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis.
(a)
Identification. A knee joint tibial (hemi-knee) metallic resurfacing uncemented prosthesis is a device intended to be implanted to replace part of a knee joint. The device limits minimally (less than normal anatomic constraints) translation in one or more planes. It has no linkage across-the-joint. This prosthesis is made of alloys, such as cobalt-chromium-molybdenum, and is intended to resurface one tibial condyle. The generic type of device is limited to those prostheses intended for use without bone cement (§ 888.3027).(b)
Classification. Class II.