(33 days)
The TheraKnit Garment Electrodes are cutaneous electrodes to be used with legally marketed TENS and NMES stimulating devices. The knitted garments deliver the stimulation signals generated by the stimulator to the body parts with which they are in contact. These body parts include hands, feet, arms, legs, shoulder, back (pads).
The TheraKnit Garment Electrodes are conductive garments knitted from a continuous silver coated Nylon yarn into the form of gloves, socks, sleeves and flat fabric used for pads. The conductivity is derived from the silver content of the Nylon yarn. The garment electrodes are available in a variety of sizes ranging from small to extra large for gloves and small to large for socks and sleeves. The elongation property of the nylon yarn provides some elasticity which ensures firm skin contact. The devices can be used dry or wet when in contact with the skin. The entire surface of each garment electrode is very conductive having a resistance of less than 7 ohms per inch. This low resistance provides low current density with uniform current distribution.
Acceptance Criteria and Device Performance Study for TheraKnit Garment Electrodes
The provided 510(k) summary for the TheraKnit Garment Electrodes (K053214) outlines its claims of substantial equivalence to predicate devices, but it does not explicitly state quantitative acceptance criteria or detailed results of a study designed to prove the device meets specific performance thresholds.
Instead, the submission focuses on demonstrating equivalence through shared technological characteristics and general bench testing, which is common for devices seeking 510(k) clearance based on substantial equivalence.
Here's an analysis based on the provided text, addressing your specific points where information is available:
1. Table of Acceptance Criteria and Reported Device Performance
| Acceptance Criteria (Implied/Inferred) | Reported Device Performance (from text) |
|---|---|
| Electrical Resistance (Conductivity) | Less than 7 ohms per inch. (Stated for both TheraKnit and predicate devices). This is critical for uniform current distribution and low current density. |
| Material Composition | Knitted from a continuous silver-coated Nylon yarn. |
| Form Factor | Garments (gloves, socks, sleeves, flat fabric for pads). |
| Intended Use | To deliver stimulation current for pain relief with TENS/NMES devices. |
| Target Population | Patients needing pain relief via electrostimulation on hands, feet, arms, legs, low back, and shoulder. |
| Washability | Washable with conventional detergents without adverse effect on conductivity. |
| Fit/Skin Contact | Provides a snug elastic fit. |
| Biocompatibility/Safety | Not explicitly stated, but implied by regulatory clearance and similarity to predicate devices. |
| Compatibility with TENS/NMES devices | Receives electrostimulation signal from legally marketed TENS/NMES devices via a lead wire and snap connector. |
| Overall Design Requirements | Device meets design controls and design requirements. |
| Equivalence to Predicate Devices | TheraKnit is "substantially equivalent" to predicate devices. |
Study Proving Acceptance Criteria:
The study proving these (mostly implied) acceptance criteria is described as "Bench testing" and "Comparative testing":
- Bench testing: "Bench testing has been done with this device demonstrating that it meets design controls." This is a general statement indicating the device underwent internal testing to ensure it functions as designed, but specific results or quantitative criteria met are not detailed.
- Comparative testing: "Comparative testing was done between the TheraKnit garments and the predicate devices for resistance measurement and comparison." This directly addresses the electrical resistance criterion and aims to show similarity to the legally marketed predicate devices. The text states that "The resistance of the knitted garment for both TheraKnit and the predicate devices are less than 7 ohms/inch," indicating this comparative testing confirmed the TheraKnit's conductivity is within the same range as the predicates.
2. Sample Size Used for the Test Set and Data Provenance
- Test Set Sample Size: Not specified. The document does not provide any numbers for the test set used during bench or comparative testing.
- Data Provenance: Not specified. The document does not mention the country of origin of the data or whether the tests were retrospective or prospective. Given it's bench and comparative testing relating to physical properties, it would most likely be prospective laboratory testing.
3. Number of Experts Used to Establish Ground Truth for the Test Set and Qualifications
- Not Applicable. The study described focuses on technical performance characteristics (like resistance) and design controls of the device itself, rather than diagnostic accuracy or clinical outcomes that would require expert ground truth.
4. Adjudication Method for the Test Set
- Not Applicable. As the testing was technical/bench-based, there would be no need for an adjudication method typically used for clinical or image-based studies.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was Done
- No. An MRMC study was not done. The device is a cutaneous electrode, not a diagnostic imaging or AI-assisted interpretation tool that would typically involve human readers. The comparative effectiveness focused on technical specifications rather than human performance.
6. If a Standalone (i.e. algorithm only without human-in-the loop performance) Was Done
- Not Applicable (in the conventional sense). This device is not an algorithm or AI system. Its performance (e.g., conductivity) is standalone in the sense that the device itself performs this function, but the context of "standalone performance" usually refers to AI systems. Its intended use is with human-operated TENS/NMES devices.
7. The Type of Ground Truth Used
- Calibration/Measurement Standards and Predicate Device Performance. For the resistance measurements, the ground truth would be established through calibrated measuring equipment providing an objective standard for "ohms/inch." For the comparative testing, the performance of the legally marketed predicate devices served as a de facto "ground truth" or benchmark against which the TheraKnit's performance was compared to demonstrate equivalence.
8. The Sample Size for the Training Set
- Not Applicable. The device is not an AI/ML model that requires a training set.
9. How the Ground Truth for the Training Set Was Established
- Not Applicable. The device is not an AI/ML model.
§ 882.1320 Cutaneous electrode.
(a)
Identification. A cutaneous electrode is an electrode that is applied directly to a patient's skin either to record physiological signals (e.g., the electroencephalogram) or to apply electrical stimulation.(b)
Classification. Class II (performance standards).