title: Tibial ACL insertion site length: correlation between preoperative MRI and intra-operative measurements.
abstract: OBJECTIVE
  This study was undertaken primarily to identify the tibial insertion site length of ruptured ACL fibres in patients undergoing primary ACL reconstruction. A secondary aim was to evaluate the correlation of pre- and intra-operative measurements.
  
  
  METHODS
  In 146 patients undergoing primary ACL reconstruction, a preoperative measurement on MRI of the tibial ACL insertion site length was taken by two raters and then compared with single surgeon's intra-operative measurements using a specialized ruler. Inclusion criteria were primary ACL reconstruction and MRI performed within 3 months prior to surgery on one specific MRI machine at the study centre. Inter-rater and intra-rater reliability based on intra class correlation (ICC) was calculated. Additionally, correlation between preoperative and postoperative measurements and the anthropometric data was assessed using Pearson correlation.
  
  
  RESULTS
  The tibial ACL insertion site had a mean length of 16.6 ± 1.6 mm (11.9-21.0) as measured by MRI, and 16.4 ± 1.6 mm (11.0-20.0) as measured intra-operatively. The ICCs for intra- and inter-rater reliability of the MRI measurements were 0.99 (95 % CI 0.97; 0.99; p < 0.001) and 0.81 (95 % CI 0.75; 0.86; p < 0.001), respectively. Regression analysis demonstrated, after controlling for subject height and weight, that the MRI measurements significantly predicted intra-operative measurement of tibial insertion site length (β = 0.796; R (2)-change 0.77; p < 0.001).
  
  
  CONCLUSIONS
  Preoperative measurement of the tibial ACL length is possible using MRI and can be a valuable aid in more efficient preoperative planning given the knowledge of expected dimensions of special knee structures.
  
  
  METHODS
  III.
authors.affiliation: Department of Orthopaedic Surgery, University of Pittsburgh, Kaufman Building Suite 1011, 3471 Fifth Avenue, Pittsburgh, PA, 15213, USA. hwidhalm@me.com.|Department of Trauma Surgery, Medical University of Vienna, Vienna, Austria. hwidhalm@me.com.
authors.forename: Harald K
authors.initials: HK
authors.lastname: Widhalm
authors.affiliation: Department of Orthopaedic Surgery, University of Pittsburgh, Kaufman Building Suite 1011, 3471 Fifth Avenue, Pittsburgh, PA, 15213, USA.
authors.forename: Levent
authors.initials: L
authors.lastname: Surer
authors.affiliation: Department of Orthopaedic Surgery, University of Pittsburgh, Kaufman Building Suite 1011, 3471 Fifth Avenue, Pittsburgh, PA, 15213, USA.
authors.forename: Nikhil
authors.initials: N
authors.lastname: Kurapati
authors.affiliation: Department of Orthopaedic Surgery, University of Pittsburgh, Kaufman Building Suite 1011, 3471 Fifth Avenue, Pittsburgh, PA, 15213, USA.
authors.forename: Claudia
authors.initials: C
authors.lastname: Guglielmino
authors.affiliation: Department of Orthopaedic Surgery, University of Pittsburgh, Kaufman Building Suite 1011, 3471 Fifth Avenue, Pittsburgh, PA, 15213, USA.
authors.forename: James J
authors.initials: JJ
authors.lastname: Irrgang
authors.affiliation: Department of Orthopaedic Surgery, University of Pittsburgh, Kaufman Building Suite 1011, 3471 Fifth Avenue, Pittsburgh, PA, 15213, USA.
authors.forename: Freddie H
authors.initials: FH
authors.lastname: Fu
mesh_terms: D000293:Adolescent; D000328:Adult; D016118:Anterior Cruciate Ligament / Q000033:anatomy & histology* / Q000000981:diagnostic imaging / Q000601:surgery; D000070598:Anterior Cruciate Ligament Injuries / Q000000981:diagnostic imaging / Q000601:surgery*; D059549:Anterior Cruciate Ligament Reconstruction; D005260:Female; D006801:Humans; D007430:Intraoperative Care; D007719:Knee Joint / Q000033:anatomy & histology / Q000000981:diagnostic imaging / Q000601:surgery; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011300:Preoperative Care; D015203:Reproducibility of Results; D013977:Tibia / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D055815:Young Adult
keywords: Anterior cruciate ligament reconstruction; Insertion site; Inter-rater reliability; Length; MRI