Perineal Pressure During Hip Arthroscopy Is Reduced by Use of Trendelenburg: A Prospective Study With Randomized Order of Positioning

Background: The use of traction during hip arthroscopy is commonly used to provide safe joint access and to improve visualization. However, traction during hip arthroscopy has been associated with complications ranging from transient neuropraxias to devastating soft-tissue necrosis. Trendelenburg positioning may be helpful, but the degree to which this is true is not well understood.

Questions/purposes: To determine whether there would be a reduction in perineal pressure at 5°, 10°, and 15° of Trendelenburg compared with baseline (0° of Trendelenburg) while in the modified supine position during hip arthroscopy.

Methods: A consecutive cohort of 50 patients treated with hip arthroscopy by a single, high-volume orthopaedic surgeon was analyzed. There were 30 females and 20 males in this study, with a mean age of 36 ± 16 years (range, 14 to 66 years); mean BMI was 26 kg/m. In the operating room, patients were placed in the modified supine position on a traction extension table with a well-padded perineal post. A standard blood pressure cuff was secured to the post to measure pressure exerted on the perineum as traction was applied to distract the hip. For each patient, pressure against the perineum was measured at four different positions using a digital level: 0°, 5°, 10°, and 15° of Trendelenburg. These positions were tested in a random order for each patient. Mean pressure was compared within patients under the four-period crossover design using a repeated-measure (mixed) ANOVA model. Examination of the residual error quantile plot showed that the pressure data followed a normal distribution, making the use of a parametric model appropriate. Tests were made for period and order effects.

Results: Compared with baseline (0° or no Trendelenburg) there was a reduction in pressure of 4.4 (15.5%) at 5° of Trendelenburg (p = 0.203), 8 (28%) at 10° of Trendelenburg (p = 0.022) and 13.1 (46%) at 15° (p = 0.006). These results were maintained regardless of the sequence of positions used in each patient (0°, 5°, 10°, 15°).

Conclusions: Trendelenburg positioning of 10° and 15° during hip arthroscopy resulted in decreased perineal pressure compared with the neutral (0°) position. This technique is intended to harness gravity to exert the majority of countertraction while retaining the perineal post as a backup patient stabilizer. Routine introduction of Trendelenburg during hip arthroscopy reduces perineal pressure against the post, which may decrease complications related to traction and perineal pressure. Future studies should assess whether the observed differences in perineal pressure will reduce the frequency of post-related complications after hip arthroscopy.

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