Ankle Impingement Syndromes: A Pictorial Review

Purpose or Learning Objective: To recognize imaging findings of different types of ankle impingement syndromes.

Methods or Background: Ankle impingement syndromes are a common cause of chronic ankle pain, usually secondary to acute trauma or repetitive microtrauma. They are caused by entrapment of soft tissue or osseous structures. Based on their anatomical location, they can be classified as anterolateral, anterior, anteromedial, posteromedial, or posterior syndromes. The clinical diagnosis is usually made through history and physical examination. Radiographs, computed tomography (CT), and magnetic resonance imaging (MRI) help evaluate the anatomical mechanism, as well as to rule out other causes of ankle pain. Initial treatment is usually conservative.

Results or Findings:

Anterolateral Impingement:

Symptoms: Uncommon cause of chronic lateral ankle pain.

Cause: (Repetitive) minor inversion injuries of the anterior talofibular ligament (ATFL) or anterior inferior tibiofibular ligament (AITFL) without mechanical instability.

Imaging: Abnormal soft tissue mass, fibrosis, or synovitis in the anterolateral gutter, in advanced cases forming a hyalinized meniscoid lesion, synovitis, or hypertrophy of the AITFL.

Anterior Impingement:

Symptoms: Common cause of chronic ankle pain and limited dorsiflexion.

Cause: Repeated stress in ankle dorsiflexion leading to direct microtrauma (e.g., soccer players or ballet dancers).

Imaging: Beak-like osteophyte formation at the anterior tibial plafond and the opposed talus with bone marrow edema, osteochondral loose bodies, and synovitis of anterior capsular recess.

Anteromedial Impingement:

Symptoms: Rare cause of chronic ankle pain associated with dorsiflexion and inversion.

Cause: Usually associated with acute injury of medial/lateral ligaments (especially the anterior tibiotalar ligament [ATTL]) or repetitive microtrauma (e.g., soccer players, dancers, or cross-country runners).

Imaging: Thickening of the ATTL, soft tissue thickening anterior to the ATTL (might also form a meniscoid soft tissue lesion), osteophyte formation, chondral lesions.

Posteromedial Impingement:

Symptoms: Least common type, presenting as posteromedial ankle pain with active and passive movement.

Cause: Usually after high-energy trauma with injury of the posterior tibiotalar ligament (PTTL).

Imaging: Injury of the PTTL, hypertrophic fibrosis, and chronic inflammation due to inadequate healing, associated osteochondral or ligamentous injuries due to high-energy trauma.

Posterior Impingement:

Symptoms: Common cause of chronic deep pain and swelling within posterior ankle, mainly on plantar flexion.

Cause: Impingement of osseous (os trigonum or Stieda's process) or soft tissue structures (flexor hallucis longus tendon, posterior synovial recess, ganglion cysts).

Imaging: Bone marrow edema in talus/calcaneus/os trigonum, posterior synovitis, thickening of posterior ligaments (posteroinferior tibiofibular ligament, posterior talofibular ligament, posterior intermalleolar ligament).

Conclusion: MRI is a helpful tool to detect findings of different ankle impingement syndromes, rule out other causes of ankle pain, and evaluate the anatomical conditions causing the symptoms. Radiographs and CT can be useful to assess osseous components, especially for preoperative evaluation, if conservative treatment is unsatisfactory.

Publication History

Article published online:
26 May 2023