title: The effect of tibial rotation on varus deformity measurement.
abstract: OBJECTIVE
  Tibial osteotomy is used to treat a variety of orthopedic conditions, including reduction in pain and improvement of deformity and function. In templating for surgery, accurate radiographic measurement aids in planning for correction. The purpose of our study was to examine the effect of internal rotation and external rotation on measurement of tibial sawbone models with 5 closing wedge varus deformities at 10-degree increments between 10 and 50 degrees. One sawbone without deformity served as the control.
  
  
  METHODS
  A total of 66 radiographs were measured by 5 individuals. Measurement deviations from the control in each of the 10 positions of rotation were assessed.
  
  
  RESULTS
  In the analysis of variance models, increased rotation and varus angulation were associated with increased deviation compared with the control. In external rotation for every 10 degrees of varus angulation, the degree deviation increased 0.69 degrees. In IR for every 10 degrees of angulation, the degree deviation increased by 0.84 degrees. Internal rotation had the greatest impact. Mean differences between different rater's measurements were small (1.1+/-1.2 degrees) and correlations suggested high interrater reliability.
  
  
  CONCLUSIONS
  As the degree of rotation from neutral increased and varus angulation increased, deviation from neutral increased.
  
  
  CONCLUSIONS
  Clinically, the results of this study support the importance of proper alignment of the tibia during radiography to more precisely template surgery.
authors: Department of Orthopaedic Surgery, Medical University of South Carolina, Charleston, SC 29425, USA. mccann@musc.edu
authors: Heather
authors: H
authors: McCann
authors: Deborah F
authors: DF
authors: Stanitski
authors: William R
authors: WR
authors: Barfield
authors: John A
authors: JA
authors: Leupold
authors: Paul J
authors: PJ
authors: Nietert