Generalized Ligamentous Laxity Is an Independent Predictor of Poor Outcomes After the Modified Broström Procedure for Chronic Lateral Ankle Instability.

BACKGROUND: The modified Broström procedure for chronic lateral ankle instability (CLAI) has presented outstanding clinical results. However, after the procedure, some patients with generalized ligamentous laxity have experienced a recurrence of ankle instability.

PURPOSE: To understand the effect of generalized ligamentous laxity on prognosis and risk of recurrence in a cohort of patients with CLAI after the modified Broström procedure.

STUDY DESIGN: Cohort study; Level of evidence, 3.

METHODS: A total of 199 ankles from 188 patients underwent the modified Broström procedure for CLAI with a mean follow-up of 60.1 months (range, 48-108 months). Generalized ligamentous laxity was assessed in all patients. The Karlsson-Peterson ankle score (Karlsson score), talar tilt angle, and anterior displacement of the talus were used to evaluate clinical and radiological outcomes. Risk factors associated with clinical outcomes were evaluated using bivariate analysis and logistic regression analysis. Survival outcomes were compared using Kaplan-Meier analysis.

RESULTS: Generalized ligamentous laxity was evident in 42 cases (21.1%). The average Karlsson score improved from 54.6 ± 7.1 preoperatively to 87.9 ± 7.2 at last follow-up (P < .001). The presence of generalized ligamentous laxity was significantly associated with poor clinical and radiological outcomes. The rates of clinical failure were 10.8% and 45.2% in the nonlaxity group and the laxity group, respectively (P < .001). According to bivariate analysis, generalized ligamentous laxity, syndesmosis widening, osteochondral lesion of the talus, high preoperative talar tilt angle (>15°), and high preoperative anterior displacement of the talus (>10 mm) were significantly associated with clinical failure. Multivariate logistic regression analysis revealed that generalized ligamentous laxity was the most important independent predictor of clinical failure after the modified Broström procedure. The cumulative success rates for the nonlaxity group were significantly superior to those for the laxity group in Kaplan-Meier curves (P < .001).

CONCLUSION: Generalized ligamentous laxity is an independent predictor of poor outcomes and a risk factor of recurrent instability following the modified Broström procedure for CLAI.