Posterior Process Fractures
Anatomy
Composed of Posterolateral & Posteromedial tubercles
- separated by sulcus for FHL
- lateral larger than medial
PL tubercle
- size variable
- Superior surface non articular, attaches PTFL
- Inferior surface in continuity with posteror articular surface of Talus
PM tubercle
- also varies in size
- deep & superficial Deltoid ligaments attach
Os Trigonum
- accessory bone seen in association with PL tubercle of talus
~ 50% of feet
- may be unilateral or bilateral
- may be fused to talus or calcaneus
- relationship to PL tuberosity varies from complete separation to fusion
Mechanism
A. Forced PF
- impingement especially ballet / soccer
B. Excess DF
- increased tension on PTFL with avulsion
Examination
Tender posteriorly
Crepitus with PF
Pain with motion of Hallux in groove
DDx
Lateral process fracture
Fracture of fused os trigonum
Disruption of synchondrosis of os to talar body
Investigation
Xray
Bone Scan / CT useful in Dx
Management
Same for medial & lateral
- conservative initially
Persistent symptoms >6/12
- excision of fragement
- posteromedial or posterolateral approach
- Persistent problems from non-union not uncommon