title: Remnant-Preserving Tibial Tunnel Positioning Using Anatomic Landmarks in Double-Bundle Anterior Cruciate Ligament Reconstruction.
abstract: To assess (1) if 6 anatomic landmarks (ALs) could be arthroscopically confirmed with remnant preservation and (2) if creating tibial tunnels using these landmarks reduces individual variation and improves reproducibility in double-bundle anterior cruciate ligament (ACL) reconstruction.
  
  
  
  We retrospectively reviewed data of patients who chronologically underwent double-bundle ACL reconstruction by either referencing the footprint after remnant dissection (non-AL group) or subsequently with the ALs (AL group). Using operative videos, 3 independent observers judged whether they could confirm 6 ALs (medial intercondylar ridge, medial and lateral intercondylar tubercles, anterior horn of lateral meniscus, Parsons' knob, and L-shaped ridge) in 20 patients randomly selected from the AL group. We then compared tunnel positions between the 2 groups, measured from the anterior and medial borders of the proximal tibia and expressed as percentage of the total depth and width of the proximal tibia using 3-dimensional computed tomography.
  
  
  
  One hundred four patients (non-AL group, n = 54; AL group, n = 50) were included. All 6 ALs were arthroscopically confirmed in most cases (89.7% to 100%). The mean percentages of the anteroposterior (AP) depth for anteromedial (AM) tunnel, mediolateral (ML) width for AM tunnel, AP depth for posterolateral (PL) tunnel, and ML width for PL tunnel, respectively, were 27.8% ± 6.6%, 46.7% ± 2.8%, 41.4% ± 7.3%, and 46.1% ± 2.6% for the non-AL group and 30.7% ± 4.5%, 45.7% ± 2.2%, 45.2% ± 4.5%, and 46.9% ± 2.1% for the AL group, revealing significantly less variation in the AL group compared with the non-AL group, excluding the ML width of the PL tunnel (P = .007, .046, .002, .209, respectively).
  
  
  
  Six landmarks could be reliably confirmed in cases with remnant preservation, and creating tibial tunnels using these landmarks were reproducible and resulted in less individual variation.
  
  
  
  Level III, retrospective comparative study.
authors.affiliation: Department of Orthopedic Surgery, Shinshu University School of Medicine, Matsumoto, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Shimodaira
authors.affiliation: Department of Orthopedic Surgery, Shinshu University School of Medicine, Matsumoto, Japan. Electronic address: kten@shinshu-u.ac.jp.
authors.forename: Keiji
authors.initials: K
authors.lastname: Tensho
authors.affiliation: Department of Orthopedic Surgery, Shinshu University School of Medicine, Matsumoto, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Akaoka
authors.affiliation: Department of Orthopedic Surgery, Shinshu University School of Medicine, Matsumoto, Japan.
authors.forename: Seiji
authors.initials: S
authors.lastname: Takanashi
authors.affiliation: Department of Orthopedic Surgery, Shinshu University School of Medicine, Matsumoto, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kato
authors.affiliation: Institute for Biomedical Sciences, Interdisciplinary Cluster for Cutting Edge Research, Shinshu University School of Medicine, Matsumoto, Japan.
authors.forename: Naoto
authors.initials: N
authors.lastname: Saito
mesh_terms: D000293:Adolescent; D000328:Adult; D059925:Anatomic Landmarks; D059549:Anterior Cruciate Ligament Reconstruction / Q000379:methods*; D001182:Arthroscopy; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging / Q000601:surgery; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013977:Tibia / Q000000981:diagnostic imaging / Q000601:surgery*; D014743:Videotape Recording; D055815:Young Adult