Fri., 10/5/12 Foot & Ankle, PAPER #43, 10:29 am OTA-2012
A New Look at the Hawkins Classification for Talar Neck Fractures: Which Features of Injury and Treatment Are Predictive of Osteonecrosis?
Stephen G. Reichard, MD; Heather A. Vallier, MD; Alysse J. Boyd, MA;
Timothy A. Moore, MD;
MetroHealth Medical Center, Cleveland, Ohio, USA
Background/Purpose: Despite improvements in surgical techniques, including usage of dual anteromedial and anterolateral exposures and versatile implants, talar neck fractures remain challenging injuries to manage. Osteonecrosis (ON) and posttraumatic arthrosis (PTA) are reported commonly. Initial fracture displacement and length of time dislocated versus the time until definitive fixation have been considered potential risk factors for ON. The purpose of this study was to review a large series of talus fractures, reduced expeditiously, but definitively managed with delay whenever possible to allow for improvement in soft-tissue swelling. We hypothesized that delay of fixation would not increase the risk of ON, but that initial fracture displacement, including subtalar and/or tibiotalar dislocations would be predictive. We propose dividing the Hawkins II classification into subluxed subtalar joint (IIA) and dislocated subtalar joint (IIB).
Methods: Records of 80 patients with 81 talar neck and or body fractures treated with open reduction and internal fixation (ORIF) at a Level I trauma center over 10 years were reviewed. 40 women and 40 men with mean age of 36.7 years (range, 17-72) had 78 talar neck fractures: 2 Hawkins I, 40 Hawkins II (17 IIA and 23 IIB), 32 Hawkins III, 1 Hawkins IV, 2 Hawkins IIB with an associated talonavicular dislocation, and 4 patients had displaced talar body fractures. Open fractures occurred in 24 patients (29.6%). A two-incision approach was used in 92%, and 95% of patients were stabilized with mini- and/or small-fragment implants. Comorbidities, fracture characteristics, and timing of reductions, provisional and definitive, were recorded. Complications including wound healing problems, infections, nonunions, malunions, ON, and PTA were noted.
Results: Patients were assessed after a mean 21.2 months’ follow-up. One patient (1.2%) developed deep infection, and two patients each had nonunion (2.4%) and malunion (2.4%). 15 of 81 fractures (18.5%) developed ON, but 60% of these revascularized without collapse. ON did not occur in any patients without subtalar dislocation (Hawkins I and IIA), but 24% of those with Hawkins IIB patterns developed ON (P = 0.03), and 29% of Hawkins III fractures developed ON. ON occurred after 29% of open fractures versus 14% of closed fractures (P = 0.12). 46 fractures (57%) were treated with urgent ORIF at a mean of 10.1 hours after injury (range, 5-24 hours), most because of open fractures and/or irreducible dislocations. Timing of reduction within 6, 8, 12, or 18 hours after injury was not related to risk of ON. 35 patients were treated with delayed ORIF at a mean of 10.6 days, including 9 Hawkins IIB and 9 Hawkins III fractures initially reduced with closed ± percutaneous methods at a mean of 9.5 hours after injury. Only 1 of these 18 patients developed ON (5.6%). 31 patients (38%) had some radiographic evidence of PTA, including 45% of those with associated talar body fracture, and 59% of Hawkins III injuries.
Conclusion: Treatment for fractures of the talus has evolved over recent years. Open fractures and dislocations irreducible through closed methods should be treated urgently. However, we recommend careful attention to fracture alignment through open reduction, performed on a delayed basis when initial soft-tissue swelling is severe, as long as dislocations have been reduced. Delaying fixation in such cases does not increase the risk of ON. ON was associated with initial fracture displacement, and separating Hawkins II fractures into those with (IIA) and without (IIB) subtalar dislocation was predictive of ON. ON never occurred when the subtalar joint was not dislocated. The majority of ON cases revascularized without talar dome collapse.
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