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Commentary & Perspective | ||||||||
Commentary & Perspective on This article is intriguing and quite timely for those familiar with ankle arthroscopy. The recent advent of tendoscopy has created a new opportunity for arthroscopic surgeons to visualize the tendons about the hindfoot and to employ microinvasive techniques not only for the identification of hindfoot disorders but also for their treatment. In their article, Sitler et al. have identified the ancillary portals that may be necessary for an associated diagnostic or therapeutic procedure involving either the ankle or subtalar joint with use of tendoscopy with the patient in the prone position. The author's findings were statistically validated by both MRI and gross dissection. The correlation between these two modalities appeared to be excellent. Distances between a cannula and adjacent anatomic structures were measured with use of MRI and dissection, which added more statistical validity than has been previously reported in the literature.1,2 Many of the limited studies that have been conducted in the past were done with the patient in the supine position, and the authors have carefully explained why these two positions may involve differences in visualization and in procedural difficulty.2,3 With complication rates for ankle arthroscopy reported in the literature to be as high as 9%, (and the majority of those complications being neurological in nature), this particular approach still carries with it some potential morbidity and should not be performed by the surgeon who only occasionally performs foot and ankle arthroscopy. Sitler et al. found that the average distance between the posterolateral portal site and the sural nerve was 3.2 mm (3.2 mm on dissection and 2.8 mm on MRI), which represents a very small distance that must be considered when creating a portal. A "nick and spread" technique for establishing portals about the ankle is particularly recommended when using a posterior approach to avoid some of these potential complications. The authors advocated staying in close proximity to the Achilles tendon, and this is a very pertinent point, not only with the patient in the supine position but in the prone position as well. They reported a very interesting finding on the anatomical course of the sural nerve. Most posterolateral portals established with the patient in the supine position are made by inclining the portal from distal to proximal. This approach generally avoids the sural nerve; however, placing a portal parallel to and at the level of the ankle joint involves greater risk to the sural nerve. Therefore, it is important to start this portal somewhat more inferiorly to avoid damage to the sural nerve. It was with great interest that I read the measurements from the posteromedial portal to the tibial nerve and its medial calcaneal branch. These structures have always been the most vulnerable structures encountered in a posteromedial portal. Should one choose to employ this portal, the authors advise staying very close to the Achilles tendon and entering the joint at a perpendicular angle to avoid damaging the tibial nerve The majority of ankle pathology treated arthroscopically is in the anterior compartment (with the exception of posteromedial osteochondritis dissecans and loose bodies), and only an average of 54 % of the talar dome could be visualized with use of the posterolateral and posteromedial portals in this study. Therefore, the indications for ankle arthroscopy with the foot in the prone position in patients who have anterior ankle pathology are limited. A full capsulectomy may be performed for better visualization of the subtalar joint and the ankle joint. Some authors who advocate posterior ankle arthroscopy have also recommended this4, but the long-term effects of posterior capsulectomy in our patient population are uncertain. The findings of this anatomic study are relevant to all surgeons who perform ankle arthroscopy and may be used to facilitate accurate and safer placement of posterior portals. *The author did not receive grants or outside funding in support of the research or preparation of this manuscript. He did not receive payments or other benefits or a commitment or agreement to provide such benefits from a commercial entity. No commercial entity paid or directed, or agreed to pay or direct, any benefits to any research fund, foundation, educational institution, or other charitable or nonprofit organization with which the author is affiliated or associated. References 1. Parisien JS, Vangsness T, Feldman R. Diagnostic and operative arthroscopy of the ankle. An experimental approach. Clin Orthop. 1987;224:228-36. | ||||||||
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