Ankle Approach Selection: Defining Eight Ankle Approaches Exposure Segment and Area
Authors: Palma Joaquin , Urrutia Tomas , Faundez Jorge 
Published: January 2022

Category:

Ankle; Trauma

Introduction/Purpose:

Ankle and tibial plafond fractures are a frequent problems in everyday practice. To achieve the best possible outcome, proper soft tissue handling and joint surface restoration is mandatory, therefore, approach selection is of vital importance. Currently, there is no consensus nor evidence-based data regarding this critical planning step, and published guidelines are based on expert opinion. The aim of this study was to measure exposure segment and amount of area exposed by 8 different approaches and to provide objective data to be used as a tool in approach selection.

Methods:

We performed a descriptive cadaveric study. We included the following approaches: anteromedial, anterolateral, direct lateral, posterolateral, posterior paramedian, posterior modified posteromedial, anterior modified posteromedial and direct medial approach. Each approach was performed four times. All incisions where standardized in length and centered 1cm proximal to the tibiotalar joint. After retracting flaps, we took one picture of each approach at a standardized distance, using a 1cm mark as a witness and calculated bone exposure area. On a second stage, all specimens where frozen and used to perform an axial cut 1cm proximal to the tibiotalar joint. A new picture was then obtained of each approach at a standardized distance. The amount of segment exposed by each approach was expressed in degrees, using two reference axes: the mediolateral malleolar axis and an anteroposterior axis at it center. 0° was stablished at the medial malleolus and 90° at the anterior edge.

Results:

We obtained the following median exposed area for the studied approaches: anteromedial: 18,36cm2, anterolateral: 8,52cm2, direct lateral: 12,72cm2, posterolateral: 9,40cm2, posterior paramedian: 12,18cm2, posterior modified posteromedial: 10,42cm2, anterior modified posteromedial: 12,37cm2 and direct medial: 15,66cm2. The median exposed segment of each approach was: anteromedial: 4°-99°, anterolateral: 50°-170,5°, direct lateral: 137°-200°, posterolateral: 187°-258°, posterior paramedian: 202°-297°, posterior modified posteromedial: 215°-305°, anterior modified posteromedial: 242°-311° and direct medial: 21°- 309,5°. The biggest area of exposure was provided by the anteromedial approach (18,36cm2) and the greatest exposed segment was that of the anterolateral approach (120°). On the other hand, the smallest exposed bone area was that of the anterolateral approach and the smallest segment with the direct lateral approach (63°). A comparative view of the exposed segments is showed in Figure 1.

Conclusion:

When comparing results focused on posteromedial approaches, the posterior paramedian approach is the one that best combines exposure area and segment. Posterior paramedian approach also allows good access to the posterolateral tibial surface. Based on our results, we propose combining posterior paramedian and posterior modified posteromedial approach, using a single incision and the FHL tendon as a mobile window to manage complex posterior tibial fractures with posteromedial and posterolateral extension. We believe that by defining area and segment exposed by different ankle approaches we provide surgeon with objective data that could help in approach or approaches selection.