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

Where Are We Now?

During the last decade, hip arthroscopy has emerged as the most-widely proposed treatment option for pre-arthritic hip disease such as femoroacetabular impingement syndrome [8]. Still, complications have been reported following hip arthroscopy, and many of these—such as pudendal neuralgia and compression-related soft-tissue necrosis [1, 3]—result from the traction applied to the joint during the procedure in order to improve the view. Traction also affects vascular and neurologic structures, including decreased blood flow of the popliteal vein and altered somatosensory evoked potentials both in the surgical and contralateral limbs, findings that are independent of traction time [4]. Some surgeons seek to minimize complications like these by using a hip distractor device [2] or by post-free Trendelenburg arthroscopy [6], but the hip distractor itself may be associated with complications related to its invasiveness. For all of these reasons, reducing traction-related complications is important, and so the current study by Lall and colleagues [5] is timely.

In the current study, Lall and colleagues [5] studied four different Trendelenburg positions (0°, 5°, 10°, and 15°), and found that perineal pressure was reduced by about 15 mm to 20 mm Hg at 10° and 15° of Trendelenburg compared to a baseline of 0°.

Where Do We Need To Go?

Reducing the pressure at the post and eventually dorsum of the foot as described by Lall and colleagues [5] is certainly an important step to reduce traction-related complications. Having said that, applying Trendelenburg will add gravitational forces to both lower extremities. I am concerned that because of this, the loads seen by neurovascular structures and muscles [4] may not be prevented by this technique. The joints of the distracted extremity (ankle, knee, hip, and potentially spine) may still be exposed to these applied forces. Traction-induced soft-tissue damage could perhaps be mitigated if we could distract the hip, but not apply forces across the remaining joints of the lower extremities during hip arthroscopy. In 2010, I was part of a group that filed a patent for a method of maintaining distraction of the hip using inflatable balloons [7]. We believed the proposed method could minimize damage to intervening soft tissues of the leg while maintaining distraction of the hip. Even moving the hip was a proposed advantage of that technique. Currently, however, such a method has not been fully tested for sufficient visualization of the hip or for performing more-complex interventions through an arthroscope. In addition, using balloon spacers may bear unknown risks to the utilized materials for intra-articular structures. Future studies will be needed to see whether this approach should see wider adoption in practice.

As traction appears likely to remain the dominant approach during hip arthroscopy for the foreseeable future, the effect of Trendelenburg position on the nerves, vessels and soft tissues should be better delineated.

How Do We Get There?

We still need to define the feasibility of intra-articular expansion devices like balloon spacers as well determine whether their intra-articular pressures exceeds tissue tolerance levels. Such devices might even be useful for mini-open approaches to the hip as a way to allow access to the joint, which currently is not possible. If the proof of concept would be given, this could be compared to external hip distractors and postless distraction as less traumatic ways to achieve access to the hip.

Until or unless one of those other approaches supplants conventional traction through a perineal post, we need to get a better handle on the problems associated with traction. Studies using techniques such as intra-operative neuromonitoring and the quantification of biomarker release such as creatine phosphokinase D-dimer, C-reactive protein could either justify the use of our current methods or further push us towards alternative techniques.