A Smaller Tibiotalar Sector Is a Risk Factor for Recurrent Anterolateral Ankle Instability after a Modified Broström-Gould Procedure

Background: Several demographic and clinical risk factors for recurrent ankle instability have been described. The main objective of this study was to investigate the potential influence of morphologic characteristics of the ankle joint on the occurrence of recurrent instability and the functional outcomes following a modified Broström-Gould procedure for chronic lateral ankle instability. Methods: Fifty-eight ankles from 58 patients (28 males and 30 females) undergoing a modified Broström-Gould procedure for chronic lateral ankle instability between January 2014 and July 2021 were available for clinical and radiological evaluation. Based on the preoperative radiographs, the following radiographic parameters were measured: talar width (TW), tibial anterior surface (TAS) angle, talar height (TH), talar radius (TR), tibiotalar sector (TTS), and tibial lateral surface (TLS) angle. The history of recurrent ankle instability and the functional outcome using the Karlsson Score were assessed after a minimum follow-up of 2 years. Results: Recurrent ankle instability was reported in 14 patients (24%). The TTS was significantly lower in patients with recurrent ankle instability (69.8 degrees vs 79.3 degrees) ( P < .00001). The multivariate logistic regression model confirmed the TTS as an independent risk factor for recurrent ankle instability (OR = 1.64) ( P = .003). The receiver operating characteristic curve analysis revealed that patients with a TTS lower than 72 degrees (=low-TTS group) had an 82-fold increased risk for recurrent ankle instability ( P = .001). The low-TTS group showed a significantly higher rate of recurrent instability (58% vs 8%; P = .0001) and a significantly lower Karlsson score (65 points vs 85 points; P < .00001). Conclusion: A smaller TTS was found to be an independent risk factor for recurrent ankle instability and led to poorer functional outcomes after a modified Broström-Gould procedure. Level of Evidence: Level IV, retrospective cohort study.