Intra-articular Pressure Changes during Stifle Arthroscopy Using a Cadaver Model

Abstract Objective  The aim of the study was to measure canine stifle intra-articular pressures (IAP) during arthroscopy using three different fluid pump pressure (FPP) settings. Study Design  Frozen thawed canine cadavers were used. The stifle was distended using a 2.7 mm arthroscope connected to a commercial fluid pump. Intra-articular pressure was measured using a portable pressure gauge connected to an intra-articular 18 G needle. Intra-articular pressure was recorded during stifle extension, 90 degrees flexion and full flexion at three different FPP (30, 50, 80 mm Hg). Results  Testing was performed on 27 stifles. Intra-articular pressure significantly increased at higher FPP ( p  < 0.01). At FPP 30, 50, and 80 mm Hg, the mean IAP was 51.8 (95% confidence interval [CI]: 41.3–62.2), 103.3 (95% CI: 92.8–113.7), and 175.2 mm Hg (95% CI: 164.8–185.6), respectively. At FPP 30 and 50 mm Hg, IAP always remained under 170 mm Hg. At 80 mm Hg, IAP raised to or above 170 mm Hg in 11/14 stifles. Stifle position significantly affected IAP ( p  < 0.01). Changing stifle position from 90 degrees flexion to extension significantly decreased IAP by 22.4 mm Hg (95% CI: 16.2–28.5), and changing to full flexion significantly increased IAP by 20.9 mm Hg (95% CI: 14.8–27.1; p  < 0.01). Conclusion  Our results suggest that caution should be used during stifle arthroscopy to limit risk for iatrogenic capsular damage. Fluid pump pressure 30 mm Hg is considered safe when using a 2.7 mm arthroscope and high flow cannula. If higher FPP is necessary for visualization, duration of stifle flexion should be limited. Fluid pump pressure 80 mm Hg should be avoided.