|
Age / Sex : 11 / F
C.C.: posterior ankle pain exacerbated by plantar flexion or dorsiflexion
1) What is your impression?
Courtesy : Kil Ho Cho, MD., Yeungnam University College of Medicine
Diagnosis: Os trigonum SD
Discussion
Findings:
- a well defined os trigonum on plain radiography
- bone marrow edema in the os trigonum and the adjacent posterior talus on MR images
Differential Diagnosis:
- Os trigonum syndrome * synonyms: posterior impingement syndrome, talar compression syndrome
- fracture of lateral tubercle of talus (Shepherd's fracture)
Diagnosis: Os trigonum syndrome (posterior impingement syndrome)
Discussion:
1) occurs when the trigonal process of the talus or the os trigonum is compressed between the posterior tibia and the posterior calcaneus during forced plantar flexion
2) Clinical features - posterior ankle pain : exacerbated by plantar flexion or dorsiflexion - posterior tenderness : anterior to and not involving Axchilles tendon - palpable soft tissue thickening
3) Imaging features : Plain, CT, US - prominent lateral talar process or os trigonum - fracture not evident on plain radiography - symptomatic os trigonum :↑ activity * negative scan excludes this diagnosis
4) Imaging features : MRI - BM edema in lateral talar tubercle or os trigonum - fracture line or fluid in synchondrosis (os trigonum fracture) - posterior capsular or ligament thickening - Synovitis : posterior synovial recess of subtalar and tibiotalar joint FHL tendon sheath
5) Management a) rehabilitative physiotherapy b) imaging guided injection of steroid or local anesthetic into area of focal capsular thickening or os trigonum synchondrosis c) surgical treatment - arthroscopic resection of osseous abnormaluty and soft tissue abnormality with washout of joint
References:
1. Nathalie J. Bureau, Étienne Cardinal, Roger Hobden, and Benoit Aubin. Posterior Ankle Impingement Syndrome: MR Imaging Findings in Seven Patients Radiology 2000; 215:497-503
|
