CLASSIFICATION

Hawkins³ introduced the popular classification system of talar neck fractures that remains commonly used today. This system is based on the degree of fracture fragment displacement and divides talar neck fractures into three groups. Type I fractures are nondisplaced. Type II fractures are displaced with subtalar subluxation or dislocation. Type III talar neck fractures are displaced with dislocation of the subtalar and tibiotalar joints. This classification system was modified by Canale and Kelly⁴ in 1978 to include type IV fractures that involve not only dislocation of the subtalar and tibiotalar joints but also dislocation of the talar head from the talonavicular joint.

CLOSED VERSUS OPEN MANAGEMENT

The first question that must answered when taking care of a patient with a displaced talar neck fracture is whether open reduction and internal fixation (ORIF) is indicated. Traditionally, concerns regarding the development of AVN and post-traumatic arthritis have led to the general consensus that displaced talar neck fractures require ORIF.

In the twentieth century, before Hawkins’s work, several clinical series on talus fractures were reported.^5–8 In 1919, Anderson coined the term aviator’s astragalus after observing this injury in downed pilots.⁵ In 1952, Coltart⁶ reported a large Level IV clinical series examining this injury in British Air Force pilots during World War II. In this series, a poor outcome was associated with inadequate reduction of the subtalar joint, leading the author to advocate anatomic reduction with or without internal fixation.

Subsequently, Kenwright and Taylor⁷ examined 58 talus fractures in civilians. In 14 patients with talar neck fractures and subtalar subluxation, closed reduction and cast immobilization was attempted; however, in 10 patients (71%), satisfactory reduction could not be obtained or maintained, and open reduction was necessary. In some instances (the authors did not specify how many), the reduction was held with a Kirschner wire. Similar results were noted for talar neck fractures with tibiotalar dislocation. As such, the authors conclude that “a good result occurs only if accurate reduction is effected and maintained.”⁷

If these studies are considered to be Level II prognostic studies (i.e., investigating the outcome of the injury with and without reduction), they constitute fair evidence (grade B) that for displaced talar neck fractures, some form of reduction is necessary. The question then remains, is ORIF necessary?

In 1970, Hawkins’³ landmark review and classification system of talar neck fractures was published. In this retrospective review (Level IV therapeutic study, Level II prognostic study), he drew attention to the incidence of AVN after talar neck fractures and emphasized the importance of open reduction. Nevertheless, in this series, Hawkins only peripherally mentions internal fixation in two patients but does not give details regarding fracture type or method of fixation. Of the 24 type II fractures in this series, 10 were treated with closed reduction and cast immobilization, whereas 14 were treated with open reduction.³ The overall incidence of AVN for type II fractures was 42%.³ For type III fractures, 2 of these injuries were treated with closed reduction and 20 with some form of open reduction for an overall AVN rate of 91%.³

Meanwhile, Canale and Kelly⁴ used closed reduction, as well as open reduction with and without internal fixation, in their historical series. Closed reduction was limited to those fractures in which adequate alignment (defined as less than 5 mm of displacement and less than 5 degrees of angular deformity) could be obtained. Of the 30 cases of type II fractures in this series, 19 were treated with closed reduction and casting, 1 presented late and was treated with only non–weight bearing, and 10 underwent open reduction with internal fixation. The overall AVN rate for type II fractures was 50%. Meanwhile, for type III fractures, 5 underwent closed reduction and 15 had open reduction (only 11 of which had internal fixation). The AVN rate in this group was 84%.⁴

Unfortunately, in both Hawkins’³ and Canale and Kelly’s⁴ series, the incidence and rate of AVN were not stratified by treatment type. Therefore, it is difficult to draw from these two studies any conclusions as to whether open treatment provides a lower AVN rate than closed reduction.

Other studies have reported varied rates of AVN. In a large Level IV review of 123 talar neck fractures, Lorentzen and colleagues⁹ found the overall incidence rate of AVN to be 21%. The majority of the fractures in this series were treated with cast immobilization. Among the 53 type II fractures, only 4 underwent open reduction. Thirty fractures were treated with closed reduction and casting, whereas 19 were treated with no reduction and casting only. Notably, although Lorentzen and colleagues report a 21% incidence rate of AVN, 44% of the fractures in their series were nondisplaced. The incidence rate of AVN was 35% when only the displaced talar neck fractures are considered.⁹

In those studies that examine the results of ORIF, the type of fixation often varies dramatically within the study. In a Level IV retrospective review, Grob and coworkers¹⁰ report the results of ORIF in 41 displaced talar neck fractures treated with malleolar screws, Kirschner wires, or cancellous screws. In this series, the incidence rate of AVN was only 16%.¹⁰ These encouraging data would seem to indicate that ORIF does reduce the incidence of AVN when compared with previous series in which patients were more commonly treated with closed techniques. However, in Vallier and colleagues’¹¹ retrospective review (Level II prognostic study) of 102 displaced talar neck fractures in which all patients were treated with ORIF, the incidence of AVN was 39% for Hawkins group II fractures and 64% for Hawkins group III fractures.¹¹

In addition to AVN, the development of malunion and post-traumatic osteoarthritis are two other clinical concerns associated with displaced talar neck fractures. Canale and Kelly⁴