Radiographic Outcomes of Isolated Subtalar Joint Arthrodesis With Varying Fixation Technique

Subtalar joint (STJ) arthrodesis is a well-established and accepted surgical procedure utilized for the treatment of various hindfoot conditions including primary or posttraumatic subtalar osteoarthritis, hindfoot valgus deformity, hindfoot varus deformity, complex acute calcaneal fracture, symptomatic residual congenital deformity, tarsal coalition, and other conditions causing pain and deformity about the hindfoot. Union rates associated with isolated subtalar joint arthrodesis are generally thought to be favorable, though reports have varied significantly, with non-union rates ranging from 0 to 46%. Various fixation constructs have been recommended for STJ arthrodesis. The purpose of this study was to compare radiographic union in a 2-screw fixation technique to a 3-screw fixation technique for patients undergoing primary isolated STJ arthrodesis. To this end, we retrospectively reviewed 54 patients; 26 in the 2-screw group and 28 in the 3-screw group. We found the median time to radiographic union to be 9 weeks for the 2-screw cohort and 7 weeks for the 3-screw cohort. Additionally, we found that the 2-screw fixation cohort had a radiographic non-union rate of 26.9% while the 3-screw cohort had no non-unions. We conclude that the use of a 3-screw construct for isolated STJ arthrodesis has a lower non-union rate and time to union when compared to the traditional 2-screw construct and should be considered as a fixation option for STJ arthrodesis.