Rethinking Avascular Necrosis After Displaced Talus Fractures and Dislocations.

Abstract

To investigate the relationship of avascular necrosis (AVN) of the talus with postoperative outcomes and to assess the utility of the Hawkins sign and its ability to predict talar vitality following talar fracture or dislocation. Design: Retrospective cohort study. Single center, academic, Level I Trauma center. Patients with talus injuries (AO/OTA 81-A, 81-B, 81-C) treated from 2007-2017 were included.Outcome measures and comparisons: Variables analyzed included anatomic location, fracture classification, timing of surgery, reduction quality, and the presence or absence of Hawkins' sign. Outcomes measured included development of AVN, degree of collapse, union, posttraumatic arthritis, prognotistic reliability of the Hawkins's sign and secondary reconstructive surgery (SRS). Data were analyzed using binary logistic regressions. Seventy-nine patients were reviewed, 65% of which were male, with mean age of 37.7 years (range 18-83). Patients were followed for average of 32.5 months post-surgery. Of the 79 patients, 30 developed AVN (38%) and 20 of the 79 required SRS (25%). Of the 20 SRS cases, AVN was an indication for 6 cases (30%). Of the 30 AVN cases, 27 (90%) demonstrated less than 25% collapse of the talar dome, with 3 demonstrating more than 25% collapse. Age at time of surgery and a higher number of incisions were associated with AVN (B=0.051 p=0.01 and B=2.173 p=0.001). Timing of surgery (<24hrs), and anatomic reduction were not associated with the development of AVN (B=0.602 p=0.286 and B=0.641 p=0.491). Non-anatomic reduction was associated with higher rates of SRS (B=-1.777 p=0.033). Radiographic evidence of AVN was common after fractures and dislocations of the talus, with 38% of patients in this study developing AVN. However, the development of AVN did not influence the rate of SRS at follow up. This may be explained by the fact that most AVN patients (90%) had less than 25% collapse. Factors associated with AVN development included increased age at surgery and an increase in the number of incisions. The development of AVN had no detrimental clinical impact in this study. III.