Posterior ankle impingement is typically seen in athletes, primarily dancers and soccer players, secondary to dynamic and repetitive push-off maneuvers and forced hyperplantarflexion. Posterior ankle impingement results from chronic, repetitive trauma to the posterior ankle capsule, flexor hallucis longus tendon, and/or os trigonum. It is important to perform a thorough workup by isolating and testing the posterior compartment muscles and obtaining proper imaging with radiographs to identify any osseous abnormalities and MRI to evaluate the soft tissue structures. Nonsurgical treatment includes activity modification, physical therapy, and steroid injections.

OBJECTIVE: 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.
CONCLUSIONS: 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.
METHODS: IV.

Ankle impingement syndromes are a commonly encountered clinical entity seen in athletes, secondary to repetitive forceful microtrauma. Symptoms are related to impingement of osseous or soft tissue abnormalities in the ankle joint, in particular the tibiotalar joint, which may result in painful limitation of ankle movements. Imaging modalities, such as radiographs and magnetic resonance imaging, are very useful in diagnosing osseous and soft tissue abnormalities seen in different types of ankle impingement syndromes. This article reviews the classification of ankle impingement syndromes, their etiology, and clinical and radiological findings.