Outcome Comparison Between Functional Ankle Instability Cases With and Without Anterior Ankle Impingement: A Retrospective Cohort Study.

Functional ankle instability (FAI) and anterior ankle impingement (AAI) are likely to occur simultaneously. Nevertheless, how AAI affects ankle instability remains largely unknown. This study aimed to assess patients with FAI + AAI and those having FAI without AAI after arthroscopic synovectomy combined with the modified Broström procedure. Patients with chronic ankle instability who underwent surgery at the Huashan Hospital of Fudan University (China) from January 2010 to December 2015 were reviewed. Propensity score matching was performed (FAI + AAI: n = 86; FAI without AAI: n = 43). Ankle function was assessed by the American Orthopedic Foot and Ankle Society (AOFAS) and the Meislin criteria at 3 months, 1 year, and final follow-up. In the FAI + AAI group, AOFAS scores increased from 52.6 ± 7.2 to 78.6 ± 8.2, 84.2 ± 6.4, and 83.6 ± 11.3 at 3 months, 1 year, and last follow-up, respectively (p < .001). In the FAI without AAI group, AOFAS scores increased from 64.3 ± 10.5 to 85.2 ± 8.6, 91.4 ± 7.9, and 90.2 ± 9.8 at 3 months, 1 year, and last follow-up, respectively (p < .001; all p < .05 for differences between the 2 groups at each time point). The 2 groups showed similar scores based on the Meislin criteria (p = .38). Hypertrophic distal fascicle of the anteroinferior tibiofibular ligament showed lower AOFAS scores (all p < .05). Patients with FAI with or without AAI had improved outcomes with arthroscopic synovectomy combined with the modified Broström procedure; however, patients with combined FAI and AAI showed a relatively poorer outcome in comparison with those suffering from FAI alone, probably because of hypertrophic distal fascicle of the anteroinferior tibiofibular ligament.