title: Reliability and reproducibility of several methods of arthroscopic assessment of femoral tunnel position during anterior cruciate ligament reconstruction.
abstract: OBJECTIVE
  To assess interobserver and intraobserver agreement of estimating anterior cruciate ligament (ACL) femoral tunnel positioning arthroscopically using circular and linear (noncircular) estimation methods and to determine whether overlay template visual aids improve agreement.
  
  
  METHODS
  Standardized intraoperative pictures of femoral tunnel pilot holes (taken with a 30° arthroscope through an anterolateral portal at 90° of knee flexion with horizontal being parallel to the tibial surface) in 27 patients undergoing single-bundle ACL reconstruction were presented to 3 fellowship-trained arthroscopists on 2 separate occasions. On both viewings, each surgeon estimated the femoral tunnel pilot hole location to the nearest half-hour mark using a whole clock face and half clock face, to the nearest 15° using a whole compass and half compass, in the top or bottom half of a linear quadrant, and in the top or bottom half of a linear trisector. Evaluations were performed first without and then with an overlay template of each estimation method.
  
  
  RESULTS
  The average difference among reviewers was quite similar for all 4 circular methods with the use of visual aids. Without overlay template visual aids, pair-wise κ statistic values for interobserver agreement ranged from -0.14 to 0.56 for the whole clock face and from 0.16 to 0.42 for the half clock face. With overlay visual guides, interobserver agreement ranged from 0.29 to 0.63 for the whole clock face and from 0.17 to 0.66 for the half clock face. The quadrant method's interobserver agreement ranged from 0.22 to 0.60, and that of the trisection method ranged from 0.17 to 0.57. Neither linear estimation method's reliability uniformly improved with the use of overlay templates. Intraobserver agreement without overlay templates ranged from 0.17 to 0.49 for the whole clock face, 0.11 to 0.47 for the half clock face, 0.01 to 0.66 for the quadrant method, and 0.20 to 0.57 for the trisection method. Use of overlay templates did not uniformly improve intraobserver agreement for any estimation method.
  
  
  CONCLUSIONS
  There does not appear to be any advantage of using a half clock face or compass for estimating femoral tunnel position compared with a whole clock-face analogy. Visual reference aids appear to improve interobserver agreement (reliability) of circular analogies. The linear quadrant appears to be the most reliable method (fair to moderate agreement) for estimating femoral tunnel position without a visual aid for reference, but even better reliability, ranging from fair to good agreement, may be obtained by using the whole clock-face analogy with a visual aid.
  
  
  CONCLUSIONS
  Increasing femoral tunnel position reliability may improve outcomes of ACL reconstruction surgery.
authors.affiliation: Texas Arthroscopy & Sports Medicine Institute, Houston, Texas, U.S.A.. Electronic address: oilahi@mysurgeon.com.
authors.forename: Omer A
authors.initials: OA
authors.lastname: Ilahi
authors.affiliation: Texas Arthroscopy & Sports Medicine Institute, Houston, Texas, U.S.A.
authors.forename: David J
authors.initials: DJ
authors.lastname: Mansfield
authors.affiliation: Texas Arthroscopy & Sports Medicine Institute, Houston, Texas, U.S.A.
authors.forename: Luis H
authors.initials: LH
authors.lastname: Urrea
authors.affiliation: Texas Arthroscopy & Sports Medicine Institute, Houston, Texas, U.S.A.
authors.forename: Ali A
authors.initials: AA
authors.lastname: Qadeer
mesh_terms: D016118:Anterior Cruciate Ligament / Q000601:surgery; D000070598:Anterior Cruciate Ligament Injuries; D059549:Anterior Cruciate Ligament Reconstruction / Q000295:instrumentation / Q000379:methods*; D001182:Arthroscopy; D005269:Femur / Q000601:surgery*; D006801:Humans; D007719:Knee Joint / Q000601:surgery; D015588:Observer Variation; D015203:Reproducibility of Results