Posterior Arthroscopic Tibiotalar Arthrodesis: Anatomic Feasibility Study.

Abstract

Anterior arthroscopic tibiotalar arthrodesis has been well codified. A posterior approach with the patient in prone position is indicated when the anterior approach is precluded by soft tissue issues or for a 1-step procedure associated with posterior subtalar fusion. In an anatomic study, we assessed the feasibility of posterior arthroscopic tibiotalar fusion and sought to determine the arthroscopy entry points, mortise cartilage freshening quality, and risk of osseous, tendinous, vascular, and neural complications. We mapped 22 zones of the fibular tibiotalar mortise from 10 specimens. Medial and lateral para-Achilles arthroscopic approaches were used, with a 4-mm arthroscope at 30°. For chondral resection, we used a motorized burr, curette, and osteotome. The entire plafond of the tibial mortise could be freshened in all cases, but the talar dome could be freshened in its entirety in only 20% of cases. In 80%, only the posterior two thirds could be treated, because the anterior portion descending to the neck of the talus was poorly accessible. More than 50% of the area of the malleolar grooves was freshened. One medial malleolar fracture and one posterior fibular artery lesion developed. Thus, the technique was shown to be feasible, if no frontal hindfoot deformity or tibiotalar equinus is present, which would prevent satisfactory resection of the posterior and anterior talar cartilage. The procedure allows for single-step associated subtalar fusion, requiring 2 complementary arthroscopic approaches, 1 cm distally.