The posterior ankle capsule is the posterior fibrous reinforcement of the ankle joint between the posterior distal tibia and the posterior talar dome. It is reinforced by the posterior tibiofibular ligament (transverse tibiofibular ligament) and the posterior talofibular ligament laterally and the posterior tibiotalar component of the deep deltoid medially. The posterior capsule forms the anterior wall of the posterior ankle recess, traversed by the flexor hallucis longus tendon in its groove.
Limits anterior drawer and excessive dorsiflexion of the talus in the ankle mortise, provides the posterior fibrous containment of the ankle joint, and protects the posterior neurovascular structures from ankle hyperflexion.
The posterior ankle capsule is a key structure in posterior ankle impingement syndrome, where the capsule and synovium are compressed between the posterior tibia, talus, and os trigonum during forced plantarflexion in ballet dancers and footballers. Arthroscopic posterior ankle debridement addresses posterior capsular synovitis and os trigonum excision through posterior portals. In total ankle replacement, the posterior capsule is released to achieve adequate ankle joint distraction for component insertion.
Repetitive forced plantarflexion in dancers and soccer players pinches the posterior ankle capsule and synovium between the posterior tibial lip and the superior calcaneus, producing posterior ankle pain at maximal plantarflexion managed by physiotherapy, corticosteroid injection, or arthroscopic posterior ankle debridement.
