1. Ankle Impingement Syndrome
initial ankle injury
abnormal osseous & soft tissue thickening in the subacute or chronic situation
chronic ankle pain , painful limitation of ankle movement

2. Ankle Impingement Syndrome
Anterolateral Impingement
Anterior Impingement
Anteromedial Impingement
Posterior Impingement

3. Posterior Impingement
Anatomy and Causes
secondary ossification center :
years, usually fuses within 1 year - large lateral talar process (Stieda process) - failure of fusion (os trigonum)

4. Posterior Impingement
Anatomy and Causes
compression of soft tissue between posterior process of calcaneus and posterior tibia on plantar flexion of ankle
lateral posterior process of talus
os trigonum
chronic injury repetitive forced plantar flexion (usually)
acute injury avulsion fx of PTaF ligament, talar fx disruption of os trigonum

5. Lateral talar tubercle

6. Os trigonum

7. Posterior Impingement
Clinical features
posterior ankle pain exacerbated by plantar flexion or dorsiflexion
posterior tenderness anterior to and not involving Axchilles tendon
palpable soft tissue thickening

8. Posterior Impingement
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

9. Posterior Impingement
Imaging features : MRI
bone abnormality bone marrow edema in lateral talar tubercle or os trigonum fracture line or fluid in synchondrosis (os trigonum fracture)
posterior capsular or ligament thickening low to intermediate SI on T2-WI
Synovitis
posterior synovial recess of subtalar and tibiotalar joint
FHL tendon sheath

10. Posterior Impingement
Management
rehabilitative physiotherapy
imaging guided injection of steroid or local anesthetic into area of focal capsular thickening or os trigonum synchondrosis
surgical treatment arthroscopic resection of osseous abnormaluty and soft tissue abnormality with washout of joint

11. Posterior ankle ligament

12. Posterior Impingement
Prominent lateral talar tubercle focal thickening of posterior capsule

13. Posterior Impingement
focal thickening of posterior capsule adjacent to posterior talus (T)

14. Posterior Impingement
BM edema within os trigonum

15. Posterior Impingement
focal thickening of posterior capsule

16. Posterior Impingement
Prominent os trigonum BM edema in posterior talus

17. Posterior Impingement
limited plantar flexion BM edema in posterior talus and adjacent bone fragment

18. Posterior Impingement
BM edema in posterior talus and adjacent bone fragment
fragmentation of lateral talar tubercle

19. Posterior Impingement
BM edema in posterior talus
Inflammation of posterior recess of tibiotalar and subtalar joint
Incomplete fracture with osteosclerosis