Posterior Ankle Impingement
Epidemiology
Repetitive plantar flexion
- soccer players, ballet dancers
Cause
Os trigonum
FHL stenosing tenosynovitis
Soft tissue mass
Os Trigonum
Secondary centre of ossification of talus
- lateral to groove for FHL
- 2-7% of normal feet
- impinges against plafond with forced PF
- can cause FHL tenosynovitis
Examination
Pain with forced plantarflexion
Pain with resisted FHL
MRI
Classically
- synovitis over posterolateral process talus
- fluid in sheath about FHL
May also see
- posterior tibia bone oedema
- thickened posterior capsule
- os trigonum
Management
Non Operative
US guided HCLA
- good results reported
Operative
Options
1. Lateral approach
Indication
- resection of os trigonum only
2. Medial approach
Indication
- also release of FHL
Technique
- incision between medial malleolus and T achilles
- T post, FDL and neurovascular bundle anterior
- release FHL compartment, look for accessory muscle or nodule
- open capsule over os trigonum
- excise
- need to ensure don't damage posterior talus articular cartilage
FHL Tenosynovitis
Clinical
Pain behind medial malleolus
Pain with stressing FHL
Xray
No os trigonum
Arthroscopic release