title: The prognostic value of the hawkins sign and diagnostic value of MRI after talar neck fractures.
abstract: BACKGROUND
  The early diagnosis of avascular necrosis of the talus (AVN) and prediction of ankle function for talar fractures are important. The Hawkins sign, as a radiographic predictor, could exclude the possibility of developing ischemic bone necrosis after talar neck fractures, but its relationship with ankle function remains unclear. The purpose of this study was to illustrate the prognostic effect of the Hawkins sign on ankle function after talar neck fractures and to study the value of early MRI in detecting the AVN changes after talus fractures.
  
  
  METHODS
  Cases of talar neck fractures between November 2008 and November 2013 were evaluated. The occurrences of the Hawkins sign and AVN were studied. X-ray imaging was performed at multiple time points from the 4th to the 12th week after the fractures, and MRI examinations were used in the Hawkins sign negative group, with the time span ranging from 1.5 to 12 months. AOFAS scores of the Hawkins sign positive and negative groups were compared during the follow-up. Forty-four cases (48 feet) were evaluated.
  
  
  RESULTS
  The occurrence of positive Hawkins sign was 50%, 30%, and 33.3%, the incidence of AVN was 0%, 10%, and 50%, respectively, in type I, type II, and type III and IV talus fractures, respectively. The AOFAS scores showed no statistically significant difference between Hawkins sign positive group and negative group in type I and II fractures. The Hawkins sign positive group had better AOFAS scores than the negative group in type III and IV fractures. However, there was no statistically significant difference between Hawkins sign positive and negative groups when AVN cases were excluded in type III and IV fractures.
  
  
  CONCLUSIONS
  The Hawkins sign was a reliable predictor excluding the possibility of AVN. It did not have predictive value on the ankle function in low-energy fractures and may predict better ankle function in high-energy fractures. MRI can diagnose AVN during an earlier period, and we believe Hawkins sign negative patients should undergo MRI examinations 12 weeks after the fractures, especially in high-energy traumatic cases.
  
  
  METHODS
  Level III, comparative case series.
authors.affiliation: Shanghai Institute of Traumatology and Orthopaedics, Shanghai Key Laboratory for Prevention and Treatment of Bone and Joint Diseases with Integrated Chinese-Western Medicine, Ruijin Hospital, Jiao Tong University School of Medicine, Shanghai, China Department of Orthopaedics, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangdong, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Chen
authors.affiliation: Department of Orthopaedics, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangdong, China.
authors.forename: Wenzhou
authors.initials: W
authors.lastname: Liu
authors.affiliation: Shanghai Institute of Traumatology and Orthopaedics, Shanghai Key Laboratory for Prevention and Treatment of Bone and Joint Diseases with Integrated Chinese-Western Medicine, Ruijin Hospital, Jiao Tong University School of Medicine, Shanghai, China.
authors.forename: Lianfu
authors.initials: L
authors.lastname: Deng
authors.affiliation: Department of Orthopaedics, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangdong, China songsz999@163.com.
authors.forename: Weidong
authors.initials: W
authors.lastname: Song
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D016512:Ankle Injuries / Q000000981:diagnostic imaging / Q000601:surgery*; D001863:Bone Screws; D015331:Cohort Studies; D042241:Early Diagnosis; D005260:Female; D005500:Follow-Up Studies; D005593:Fracture Fixation, Internal / Q000009:adverse effects* / Q000379:methods; D017102:Fracture Healing / Q000502:physiology; D050723:Fractures, Bone / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D006801:Humans; D015601:Injury Severity Score; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D010020:Osteonecrosis / Q000000981:diagnostic imaging* / Q000473:pathology*; D011183:Postoperative Complications / Q000000981:diagnostic imaging / Q000473:pathology; D011237:Predictive Value of Tests; D011379:Prognosis; D016059:Range of Motion, Articular / Q000502:physiology; D020127:Recovery of Function; D012189:Retrospective Studies; D013628:Talus / Q000000981:diagnostic imaging / Q000293:injuries* / Q000601:surgery*; D014057:Tomography, X-Ray Computed / Q000379:methods; D055815:Young Adult
keywords: AVN; Hawkins sign; talar neck fracture