Analysis of Patients Who Underwent Ankle Replacement and Simultaneous Subtalar Fusion by Biomechanical and Clinical Evaluation

Subtalar fusion is commonly performed in post-traumatic subtalar osteoarthritis, rheumatoid arthritis, posterior tibial tendon dysfunction, tarsal coalition and primary subtalar osteoarthritis. Patients with osteoarthritis or severe dysfunction involving both the ankle and the subtalar joint may benefit from an tibiotalocalcaneal fusion (TTC) or an ankle replacement and subtalar fusion. With the development of new prosthetic designs and of surgical techniques, total ankle replacements (TAR) became a reasonable alternative to fusion with functional and quality of life improvements. A gait analysis of patients that underwent TAR and simultaneous subtalar fusion allows to study with precision and reliability the ankle range of motion (ROM). On the contrary, in healthy subjects or in patients that underwent isolated TAR this is not possible because the ankle ROM is influenced by the ROM of the subtalar joint in such a way that it is not possible to analyze the two joints separately. Also, excluding the role of the subtalar joint, it is possible to accurately analyze and compare the consequences on ankle kinematics of two different prosthetic designs.