A quantitative comparison of surgical approaches for posterolateral osteochondral lesions of the talus

Background: Exposure of the posterolateral talar dome for osteochondral autograft transfer can be challenging. The purpose of this study is to compare surgical exposures for perpendicular access to the posterolateral talar dome using osteochondral transfer instrumentation. Materials and Methods: Five surgical approaches were performed on each of eight cadaveric ankles. The sequence was: (1) Anterolateral arthrotomy with ATFL release, (2) Anterolateral tibial osteotomy, (3) Fibular osteotomy with ATFL intact, (4) Fibular osteotomy with ATFL release, and (5) Fibular osteotomy with ATFL/CFL release. (ATFL repaired between I and 2). While maintaining the orientation of the harvester perpendicular to the talar dome articular surface, osteochondral plugs were harvested as far posteriorly as possible using a 6-mm harvester. Distances from the anterior talar articular surface to the posterior aspect of the recipient site were measured. Statistical analysis used ANOVA and Fisher post hoc tests. Results: Average AP exposure (mm) and percentage of AP talar dome dimensions exposed: (1) Anterolateral arthrotomy with ATFL release: 21.2 mm (43.3%), (2) Anterolateral tibial osteotomy: 33.7 mm (68.5%), (3) Fibular osteotomy(ATFL intact): 43.2 mm (87.8%), (4) Fibular osteotomy with ATFL release: 44.9 mm (91.2%), and (5) Fibular osteotomy with ATFL/CFL release: 46.6 mm (94.6%). All osteotomies provided greater exposure than anterolateral arthrotomy with ATFL release (p < 0.0001). A significant difference was obtained between each of the fibular osteotomies and tibial osteotomy (p < 0.0001). Differences between the fibular osteotomy approaches (3 to 5) were not significant. Conclusion: Fibular osteotomy provides the greatest perpendicular exposure to the posterolateral talar dome. Anterolateral tibial osteotomy provides greater exposure than arthrotomy alone. Clinical Relevance: This study provides a guide for surgical exposures to the posterolateral talar dome for osteochondral autograft transfer.