MEASUREMENT OF INTRA-ARTICULAR PRESSURES AND TEMPERATURES DURING STIFLE ARTHROSCOPY AND MENISCAL ABLATION USING A CADAVER MODEL

Bettina Riitta Maaritta Salmelin

doi:10.7273/000004580

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MEASUREMENT OF INTRA-ARTICULAR PRESSURES AND TEMPERATURES DURING STIFLE ARTHROSCOPY AND MENISCAL ABLATION USING A CADAVER MODEL

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MEASUREMENT OF INTRA-ARTICULAR PRESSURES AND TEMPERATURES DURING STIFLE ARTHROSCOPY AND MENISCAL ABLATION USING A CADAVER MODEL

Bettina Riitta Maaritta Salmelin and Bettina Riitta Maaritta Salmelin

Washington State University

Master of Science (MS), Washington State University

01/2022

DOI:

https://doi.org/10.7273/000004580

Handle:

https://hdl.handle.net/2376/125037

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Abstract

arthroscopy

radiofrequency

stifle

The aims of the study were to measure intra-articular pressures (IAP) and temperatures (IAT) during arthroscopic meniscal ablation using a radiofrequency wand (RF). Fourteen dog cadavers (27 stifles) met the inclusion criteria for IAP measurements and 13 cadavers (26 stifles) for IAT measurements. IAPs were measured during stifle extension, ninety-degree flexion and maximal flexion at three pump pressures: +30mmHg, +50mmHg and +80mmHg. IAT measurements were recorded during intermittent 2 second, 5 second and continuous application of the radiofrequency wand (FR). During stifle arthroscopy, IAPs significantly increased with higher pump pressures (p<0.01). At pump pressures +30mmHg, +50mmHg and +80mmHg, the mean IAP was 51.8mmHg (CI: 41.3-62.2), 103.3mmHg (CI: 92.8-113.7) and 175.2mmHg (CI: 164.8-185.6) respectively. Changing stifle position from ninety-degree flexion to extension decreased IAP significantly by 22.4mmHg (CI: 16.2-28.5) and flexion significantly increased IAP by 20.9mmHg (CI:14.8-27.1) (p<0.001). At +30mmHg and +50mmHg, the IAP always remained <170mmHg regardless of stifle position. At 80mmHg, the IAP raised to or above 170mmHg in 11/14 stifles. During meniscal ablation, the mean maximum IAT was 22.3°C (CI: 20.8-23.8), 24.4°C (CI:23.0-25.9) and 34.7°C (CI: 32.9-36.5) after a 2 second, 5 second and continuous application of RF. Increasing the application time from 2 to 5 seconds significantly increased the mean IAT by 2.1°C (p=0.01) and by 12.4°C following continuous application (p<0.001). Intermittent applications did not increase IAT >45°C, however continuous applications resulted in IAT >45°C during 3/25 applications. Our results suggest that caution should be used during stifle arthroscopy and meniscal ablation. Fluid pump pressure of +30mmHg consistently result in IAPs within the safety limit (<120mmHg). If higher pump pressure settings are necessary, stifle flexion duration should be limited to limit exposure to IAP >120mmHg. Pump pressure settings of +80mmHg should be avoided to reduce the risk for permanent capsular deformation (>170mmHg). In this study, a pulsatile 2 and 5 second application did not increase temperatures above 45°C and would therefore be considered a safe technique for meniscal ablation. Continuous application of the meniscal ablator was predominantly safe, however in 12% of cases elevated IATs to chondromalacic levels.

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Title: MEASUREMENT OF INTRA-ARTICULAR PRESSURES AND TEMPERATURES DURING STIFLE ARTHROSCOPY AND MENISCAL ABLATION USING A CADAVER MODEL
Creators: Bettina Riitta Maaritta Salmelin
Bettina Riitta Maaritta Salmelin
Contributors: Peter J Gilbert (Advisor)
Steven A Martinez (Committee Member)
Briedi R Gillespie (Committee Member)
Awarding Institution: Washington State University
Academic Unit: Veterinary Medicine, College of
Theses and Dissertations: Master of Science (MS), Washington State University
Publisher: Washington State University
Number of pages: 28
Identifiers: OCLC#: 1371064233; 99900898740001842
Language: English
Resource Type: Thesis