Talar Neck Fracture Etiology / Epidemiology / Natural History
Talar neck fractures = fractures in which the inferior fracture line passes anterior to the lateral process of the talus in the region of the tarsal sinus. Talar body fractures = fractures extending into or posterior to the lateral process. (Inokuchi S, Foot Ankle Int, 1996;17: 748).
Talar neck fractures result from forced dorsiflexion.
Most common fracture of the talus.
Talar Neck Fracture Anatomy
Blood supply: the artery of the tarsal canal(posterior tibial artery) is the main blood supply to the body of the talus. It forms an anastomotic sling with the artery of the tarsal sinus (peroneal). Others=superior neck vessels from anterior tibial artery, Deltoid artery(post tibial) (Mulfinger JBJS 1970;52B:160), (Gelberman RH, Foot Ankle 1983;4:64).
60% covered with articular cartilage, no muscle originate from or insert into talus.
Lateral process: a wide, wedge-shaped prominence extending from the lateral aspect of the body of the talus; consists of two distinct articular facets: the dorsolateral and the inferomedial. The dorsolateral facet articulates with the distal fibula; the inferomedial facet forms the anterolateral portion of the subtalar joint. The lateral process is the site of insertion of the lateral talocalcaneal ligament.
Posterior process: composed of a medial and a lateral tubercle(Stieda’s process) which are separated by a groove within which lies the flexor hallucis longus tendon. The Y-shaped, bifurcate talocalcaneal ligament forms a roof over this grooveand inserts onto each tubercle. The posterior talofibular ligament inserts onto the lateral tubercle of the talus. The posterior talotibial portion of the deltoid ligament inserts onto the medial tubercle.
Os trigonum: located directly posterior to the lateral tubercle(Stieda's process). It is an accessory bone that arises from a secondary ossification center between the ages of 8 and 11 years. Generally fuses to the lateral tubercle within 1 year of its appearance. May persist as a separate ossicle, attached to the talus by a cartilaginous synchondrosis. (Grogan DP, JPO 1990;10:618)
Talar Neck Fracture Clinical Evaluation
Ankle pain and swelling, inability to ambulate.
Evaluate soft tissue injury and for open fractures.
Document neurovascular exam before and after any treatment.
Talar Neck Fracture Xray
A/P, Lateral, and Mortise Ankle and A/P, Oblique, Lateral foot xrays indicated.
Canale view-visualizes talar neck; taken with ankle in maximum plantar flexion and foot pronated 15 degrees. Radiograph directed at 75 degree angle from horizontal plane in the A/P plane. (Canale, JBJS 60A:143;1978).
Hawkins Sign=prognostic indicator following displaced neck fx’s. Subchondral radiolucency presnt 6-8 wks after fx suggests blood supply to this region.
MRI helpful to determing AVN post-operatively, but may be limited by metal from ORIF
Talar Neck Fracture Classification / Treatment
ATLS resuscitation. These can be high enegery injuries, assessment should begin with the A,B,C's.
Type I: nondisplaced - AVN 0-13% -Treatment = NWB SLC 6-10 wks with frequent follow xrays to confirm maintenance of reduction. Consider internal fixation to allow early ROM and prevent loss of reduction.
Type II: Displaced with subtalar subluxation/dislocation, intact ankle mortise -AVN 20%-50%, post-traumatic arthritis 40-90% -Treatment = closed reduction (knee flexion, ankle plantar flexion, and manual distraction of the calcaneoiusanatomic reduction, ?closed vs. open);
Type III: displaced talar neck fracture with dislocation of tibiotalar and subtalar joints. -AVN 69-100%, arthritis 40-90%, nonunion 13%, malunion 27% -Treatment = ORIF
Type IV(rare): Type III + disruption of talonavicular joint -90-100% AVN, arthritis 40-90%, nonunion 13%, malunion 27% -Treatment = ORIF
Osteonecrosis: diagnosis made by absence of Hawkins sign (lucency deep to the subchondral surface of the talar dome on an AP radiograph of the ankle 6-8 wks after injury which denotes revascularization.) ON does not always lead to collapse. Pts should be cautioned of potential collapse and followed closely.
Malunion: most commonly varus.
DVT / PE
Talar Neck Fracture Follow-Up care
Nonweigthbearing cast in a plantigrade postion for 6-8 wks; followed by ROM exercises.
Nonweightbearing should continue for at least 3 months
Herscovici D Jr, Anglen JO, Archdeacon M, Cannada L, Scaduto JM. Avoiding complications in the treatment of pronation-external rotation ankle fractures, syndesmotic injuries, and talar neck fractures. J Bone Joint Surg Am. 2008 Apr;90(4):898-908
Lindvall E, Haidukewych G, DiPasquale T, Herscovici D Jr, Sanders R. Open reduction and stable fixation of isolated, displaced talar neck and body fractures. J Bone Joint Surg Am. 2004 Oct;86-A(10):2229-34.
Vallier HA, Nork SE, Barei DP, Benirschke SK, Sangeorzan BJ. Talar neck fractures: results and outcomes. J Bone Joint Surg Am. 2004 Aug;86-A(8):1616-24.
Fleuriau Chateau PB, Brokaw DS, Jelen BA, Scheid DK, Weber TG. Plate fixation of talar neck fractures: preliminary review of a new technique in twenty-three patients. J Orthop Trauma. 2002 Apr;16(4):213-9.