Talar Neck Fractures With Proximal Extension Are a Harbinger for Worse Radiographic Outcomes.

Abstract

In this issue of FAI, Mechas et al3 reported their experience in treating talar neck fractures, describing talar neck fractures with proximal extension (TNPE). This subset of fractures, which extend proximally into the anterior aspect of the talar dome cartilage, occur commonly, and have not been previously characterized. Fractures with proximal extension have greater risk for osteonecrosis, talar dome collapse, and nonunion of the fracture, when compared to talar neck fractures (TN) contained within the neck proper. Prior reports on talar neck fractures have been limited to small, often single-institution, retrospective series of fractures. More recent studies have shared modern techniques and principles of provisional reduction, as indicated, and staged open reduction and internal fixation, often using dual surgical approaches.6-9 It is accepted that although the timing of definitive fracture fixation is not associated with development of osteonecrosis, various features of the initial injury are associated with damage to the arterial supply, and resultant risk of osteonecrosis. Some of these factors include open injuries, associated talar body fractures, and initial fracture displacement.1,2,6-9 The authors should be commended on providing a large series of fractures, treated at a single institution, for analysis. Although their work is retrospective, thus limited by sample heterogeneity, including patient demographics, comorbidities, and injury patterns, the treatment tactic was similar. They further offered a simple methodology of characterizing fractures based on plain radiography. More recently, many surgeons routinely obtain computed tomography scans in the evaluation and management of talus fractures, even for fractures that appear limited to the talar neck on plan radiography. Although apparently simple fracture pattens may not afford further detail on advanced imaging to alter the treatment plan, it is possible that the authors’ ability to discern TNPE with plain radiography would be enhanced with use of a computed tomography scan. Despite this, their method was corroborated by multiple, blinded surgeons agreeing on the fracture description. Prior literature has likely reported on talar neck fractures by combining those with and without proximal extension. The utility of a new, simple assessment of the initial fracture providing prognostic information is a valuable addition to our management of patients with these complex injuries. Notably, their report suffers from typical challenges of studying this population, generating low and inconsistent rates of follow-up. Their patients were assessed between 3 and 122 months following injury, with a median of 10 months and interquartile range of 6-18 months. For the primary outcome measurement of osteonecrosis, and the secondary outcomes of collapse and nonunion, a longer period of follow-up, minimum of 12-18 months, is more appropriate.6-9 It is probable that some patients would develop osteonecrosis after their time of follow-up, as 13 of their patients were seen for only 3 months. It is also probable that their high nonunion rates may be attributed to shorter follow-up, or to quality of initial fracture reduction.9 No mention was made regarding the need for secondary procedures to achieve fracture union. Proximal extension of the talar neck fracture was associated with greater initial fracture displacement as measured by Hawkins classification, and the rate of open fractures among TNPE was double vs TN fractures. Consistent with prior literature, the authors reported more osteonecrosis among more displaced fractures and among those with open injuries.1,2,4,6-9 They further described more osteonecrosis among patients with TNPE (49% vs 19%, P < .001), more collapse among patients with TNPE (14% vs 4%, P = .03), and more nonunion among TNPE (26% vs 9%, P = .01). Statistical accounting for Hawkins classification, tobacco smoking, and presence of diabetes mellitus was also performed, resulting in an odds ratio of 3.47 for osteonecrosis among TNPE. Another limitation of this study is a failure to assess for resolution of osteonecrosis. Although they defined osteonecrosis as sclerosis of the talar body relative to the adjacent bone, no mention is made of the improvement of this over time. Prior literature has described the resolution of osteonecrosis without talar dome collapse occurring in up to 44% of patients, more often in those with less initial fracture displacement.7,8 Although resolution may not have been identified on some patients in the current series, because of limited follow-up, provision of the appearance on most recent radiographs would be informative to the reader. The authors speculate that proximal extension of the talar neck fracture may be more likely to disrupt arterial branches entering the neck on the dorsal or plantar aspects.4,5 This appears plausible, based on local anatomy. Their theory is supported by their research findings. The significant increases in osteonecrosis, collapse following osteonecrosis, and fracture nonunion among patients with fractures of 1167350 FAIXXX10.1177/10711007231167350Foot & Ankle International article-commentary2023