title: Accurate and Easy Measurement of Sliding Distance of Intramedullary Nail in Trochanteric Fracture.
abstract: BACKGROUND
  In daily clinical practice, it is essential to properly evaluate the postoperative sliding distance of various femoral head fixation devices (HFD) for trochanteric fractures. Although it is necessary to develop an accurate and reproducible method that is unaffected by inconsistent postoperative limb position on radiography, few studies have examined which method is optimal. Therefore, the purpose of this study is to prospectively compare the accuracy and reproducibility of our four original methods in the measurement of sliding distance of the HFD.
  
  
  METHODS
  Radiographs of plastic simulated bone implanted with Japanese proximal femoral nail antirotation were taken in five limb postures: neutral, flexion, minute internal rotation, greater external rotation, and flexion with external rotation. Orthopedic surgeons performed five measurements of the sliding distance of the HFD in each of the flowing four methods: nail axis reference (NAR), modified NAR, inner edge reference, and nail tip reference. We also assessed two clinical cases by using these methods and evaluated the intraclass correlation coefficients.
  
  
  RESULTS
  The measured values were consistent in the NAR method regardless of limb posture, with an even smaller error when using the modified NAR method. The standard deviation (SD) was high in the nail tip reference method and extremely low in the modified NAR method. In the two clinical cases, the SD was the lowest in the modified NAR method, similar to the results using plastic simulated bone. The intraclass correlation coefficients showed the highest value in the modified NAR method.
  
  
  CONCLUSIONS
  We conclude that the modified NAR method should be the most recommended based on its accuracy, reproducibility, and usefulness.
authors.affiliation: Department of Orthopedic Surgery, Kobe University Graduate School of Medicine, Kobe, Japan.
authors.forename: Nobuaki
authors.initials: N
authors.lastname: Chinzei
authors.affiliation: Department of Orthopedic Surgery, Takatsuki General Hospital, Takatsuki, Japan.
authors.forename: Takafumi
authors.initials: T
authors.lastname: Hiranaka
authors.affiliation: Department of Orthopedic Surgery, Kobe University Graduate School of Medicine, Kobe, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Niikura
authors.affiliation: Department of Orthopedic Surgery, Kobe University Graduate School of Medicine, Kobe, Japan.
authors.forename: Takaaki
authors.initials: T
authors.lastname: Fujishiro
authors.affiliation: Department of Orthopedic Surgery, Kobe University Graduate School of Medicine, Kobe, Japan.
authors.forename: Shinya
authors.initials: S
authors.lastname: Hayashi
authors.affiliation: Department of Orthopedic Surgery, Kobe University Graduate School of Medicine, Kobe, Japan.
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Kanzaki
authors.affiliation: Department of Orthopedic Surgery, Kobe University Graduate School of Medicine, Kobe, Japan.
authors.forename: Shingo
authors.initials: S
authors.lastname: Hashimoto
authors.affiliation: Division of Rehabilitation Medicine, Kobe University Graduate School of Medicine, Kobe, Japan.
authors.forename: Yoshitada
authors.initials: Y
authors.lastname: Sakai
authors.affiliation: Department of Orthopedic Surgery, Kobe University Graduate School of Medicine, Kobe, Japan.
authors.forename: Ryosuke
authors.initials: R
authors.lastname: Kuroda
authors.affiliation: Department of Orthopedic Surgery, Kobe University Graduate School of Medicine, Kobe, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Kurosaka
mesh_terms: D001858:Bone Nails; D061827:Dimensional Measurement Accuracy; D005594:Fracture Fixation, Intramedullary / Q000295:instrumentation / Q000379:methods*; D006620:Hip Fractures / Q000601:surgery*; D011446:Prospective Studies; D015203:Reproducibility of Results
keywords: Hip fractures; Intramedullary nailing; Radiography