Prevalence of Ankle Charcot Neuroarthropathy Presenting in a Tertiary Care Center.

Charcot neuroarthropathy's (CN) anatomic classification was originally formulated by the Brodsky article and the Trepman et al modification, including midfoot (type 1), rearfoot (type 2), ankle (type 3a), calcaneus (type 3b), multiarticular (type 4), and forefoot (type 5). In these classic studies, ankle joint and multijoint CN are reported as 9% and 6% to 9%, respectively, but we believe ankle CN to be more common than that in a tertiary setting. We retrospectively reviewed patients presenting initially or as referral between 2004 and 2020. Initial presentation radiographs were reviewed and classified by 3 authors based on Brodsky's model with Trepman and colleagues' modification, and any discrepancies were reviewed by the fourth author. A total of 175 patients (205 feet) were assessed. This revealed 80 cases classified as type 1 (39.0%), 23 cases type 2 (11.2%), 17 cases type 3a (8.3%), 2 cases type 3b (1.0%), and 83 cases type 4 (40.5%). After subdividing type 4, total prevalence included 150 with type 1 anatomic location (73.2%), 103 type 2 (50.2%), 44 type 3a (21.5%), and still 2 type 3b (1.0%). This study revealed a similar prevalence of isolated ankle CN (8.5%) compared to the Trepman et al article (9%), however, in total, ankle CN (21.5%) occurred 2.4-times more than the original 9%. Our study also found there to be a higher prevalence of ankle CN in the setting of multiarticular CN, which has not been evaluated in past studies. The prevalence of multiarticular CN was found to be 4.5-fold greater than the Trepman article (6%-9%).