title: The adductor ratio: a new tool for joint line reconstruction in revision TKA.
abstract: OBJECTIVE
  In this study, the value of the adductor tubercle as landmark for joint line reconstruction in revision total knee arthroplasty (TKA) was investigated.
  
  
  METHODS
  On 100 calibrated full-leg standing radiographs obtained from healthy volunteers, distances from the medial epicondyle, the lateral epicondyle, the adductor tubercle, the fibular head and the centre of the knee to the joint line were determined.
  
  
  RESULTS
  The average distance to the joint line from the medial epicondyle, the lateral epicondyle, the adductor tubercle and the fibular head was found to be 27.7 mm (SD 3.0), 27.1 mm (SD 2.7), 44.6 mm (SD 4.3) and 15.1 mm (SD 3.7), respectively. The distance from the adductor tubercle (R = 0.82) and the centre of the knee (R = 0.86) to the joint line showed a strong and linear correlation with the femoral width. The medial epicondyle, the lateral epicondyle and the fibular head showed less strong correlations. There was no significant correlation with the limb alignment. The adductor ratio was defined as the distance from adductor tubercle to the joint line divided by the femoral width and was found to be 0.52 (SD 0.027) with only small inter-individual variation. The adductor ratio was the most accurate ratio and reconstructed the joint line within 4 mm of its original level in 92% of the cases.
  
  
  CONCLUSIONS
  The adductor ratio is a reliable and accurate tool for joint line reconstruction in revision TKA. It was found to be more accurate then the use of absolute distances and the epicondylar ratios. This study supports the use of the adductor tubercle for joint line reconstruction in revision TKA.
  
  
  METHODS
  II.
authors.affiliation: Department of Orthopaedic Surgery, University Hospitals Leuven, Weligerveld 1, 3212, Pellenberg, Belgium, luyckx.thomas@gmail.com.
authors.forename: T
authors.initials: T
authors.lastname: Luyckx
authors.forename: L
authors.initials: L
authors.lastname: Beckers
authors.forename: W
authors.initials: W
authors.lastname: Colyn
authors.forename: H
authors.initials: H
authors.lastname: Vandenneucker
authors.forename: J
authors.initials: J
authors.lastname: Bellemans
mesh_terms: D000328:Adult; D019645:Arthroplasty, Replacement, Knee; D001837:Body Weights and Measures; D017760:Bone Malalignment / Q000517:prevention & control; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging*; D005360:Fibula / Q000000981:diagnostic imaging*; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging*; D008297:Male; D011859:Radiography; D012086:Reoperation; D015203:Reproducibility of Results; D012737:Sex Factors; D055815:Young Adult