Chronic lateral ankle instability increases the likelihood for surgery in athletes with os trigonum syndrome

Purpose The etiology and incidence of os trigonum syndrome in professional athletes is highly variable. There is a paucity of data to ascertain why some athletes evolve towards surgery whilst others remain asymptomatic. We hypothesized that a lateral ligament ankle injury would increase the likelihood for surgery in those athletes with os trigonum syndrome. Methods Eighty professional athletes with clinical and radiological signs of os trigonum syndrome were identified to ascertain the incidence of injury to the lateral ligamentous ankle complex (acute and chronic) by magnetic resonance imaging (MRI). This cohort was subdivided into 2 groups; a surgical (n = 40) and a non-surgical (n = 40) cohort. Surgical division was decided if (1) the clinical hyper-plantar flexion test was positive, (2) a positive diagnostic ultrasound-guided injection and (3) no improvement was observed after 6 weeks of conservative rehabilitation. Results From the surgical cohort, 37 players (94.1%) had a chronic lateral ankle ligament injury on MRI, whilst 3 players (5.9%) had an acute lateral ankle ligament injury. Binary logistic linear modelling revealed that having a chronic lateral ligament injury increases the likelihood of os trigonum syndrome surgery by ten times compared to those with an acute lateral ligament injury. Conclusion Professional athletes with chronic lateral ligament ankle injury have an approximate ten times greater risk for os trigonum syndrome surgery compared to athletes with acute lateral ligament ankle injury.