Study type: Medical/biological study (experimental study)

Effects of radiofrequency energy on human articular cartilage: an analysis of 5 systems med./bio.

By: Caffey S, McPherson E, Moore B, Hedman T, Vangsness Jr CT
Published in: Am J Sports Med 2005; 33 (7): 1035-1039
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Aim of study (acc. to author)

To compare the radiofrequency probes currently on the market to determine its impact on human articular knee cartilage.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 300–600 kHz
Exposure duration: treatment times of 1 and 3 s
Probes touched the cartilage surface with 2 g of load.
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Exposure 2: 300–600 kHz
Exposure duration: treatment times of 1 and 3 s
Probes were tested at 1.0 mm off the cartilage surface.
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Exposure 1

Main characteristics
Frequency 300–600 kHz
Exposure duration treatment times of 1 and 3 s
Additional info Probes touched the cartilage surface with 2 g of load.
Exposure setup
Exposure source
Distance between exposed object and exposure source 0 mm
Chamber Five RF generators and probes, used by surgeons for arthroscopic chondroplasty: Probe A, ACD 50 probe (bipolar), setting = 3 (Arthrocare System 2000, Arthrocare Corp, Sunnyvale, Calif); probe B, Temperature Control Electrode (bipolar), setting = 55°C, 40 W (VAPR II System, Mitek Products Inc, Ethicon Inc, Westwood, Mass); probe C, Ultrablator 2.5-mm probe (monopolar), setting = 40 W (Linvatec, Largo, Fla); probe D, Vulcan TAC-CII Oratec Vulcan (bipolar), setting = 70°C, 15 W (Vulcan EAS, Oratec Interventions Inc, Menlo Park, Calif); probe E, Serf 90 (bipolar), setting = coagulation medium (Stryker Endoscopy, Santa Clara, Calif). Most probes deliver similar frequencies between 300 and 600 kHz.
Setup A balanced metal jig held the RF probe. Probes touched the cartilage surface with 2 g of load. Each probe was tested 6 times for a treatment time of 1 second and 3 seconds (12 samples per probe). All probes were additionally tested on grade III cartilage in 2-g contact with the cartilage for a treatment time of 3 seconds.
Additional info For the control groups, probe tips were not activated.
Parameters

No parameters are specified for this exposure.

Measurement and calculation details

Time was measured with a stopwatch.

Exposure 2

Main characteristics
Frequency 300–600 kHz
Exposure duration treatment times of 1 and 3 s
Additional info Probes were tested at 1.0 mm off the cartilage surface.
Exposure setup
Exposure source
Distance between exposed object and exposure source 1 mm
Setup A small spacer jig was attached to each probe to precisely position the tip 1.0 mm above the cartilage surface.
Parameters

No parameters are specified for this exposure.

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

Under these controlled in vitro conditions, with minimal radiofrequency energy application, substantial thermal damage to human articular cartilage was demonstrated. Surgeons using this technology need to be aware of the power and dangerous potential these probes can have on articular cartilage.

Study character:

Study funded by

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