title: Intraarticular Entrapment of Os Subfibulare Following a Severe Inversion Injury of the Ankle: A Case Report.
abstract: BACKGROUND
  Anterior Talofibular Ligament (ATFL) rupture is the most commonly injured anatomic structure in lateral ankle sprain. In some cases, ATFL avulsion fracture from the lateral malleolus may occur instead of purely ligamentous injuries. The ATFL avulsion fracture is detected as a small ossicle at the tip of lateral malleolus on direct radiographs, which is called os subfibulare in chronic cases.
  
  
  METHODS
  Severe displacement of this ossicle to the tibiotalar joint space is an extremely rare injury. Herein, a case of intra-articular entrapment of os subfibulare following a severe inversion injury of the ankle, which caused a diagnostic challenge was presented.
  
  
  CONCLUSIONS
  To the best of our knowledge, this is the first case of entrapment of os subfibulare in the talotibial joint space. Fixation of the os subfibulare to lateral malleolus resulted in union and excellent functional results.
authors.affiliation: Department of Orthopedics and Traumatology, Antalya Education and Research Hospital, Antalya, Turkey.
authors.forename: Ozkan
authors.initials: O
authors.lastname: Kose
authors.affiliation: Department of Orthopedics and Traumatology, Antalya Education and Research Hospital, Antalya, Turkey.
authors.forename: Omer Faruk
authors.initials: OF
authors.lastname: Kilicaslan
authors.affiliation: Department of Orthopedics and Traumatology, Antalya Education and Research Hospital, Antalya, Turkey.
authors.forename: Ferhat
authors.initials: F
authors.lastname: Guler
authors.affiliation: Department of Orthopedics and Traumatology, Antalya Education and Research Hospital, Antalya, Turkey.
authors.forename: Cemil
authors.initials: C
authors.lastname: Aktan
keywords: Ankle Sprain; Anterior Talofibular Ligament; Os Subfibulare