title: Arthroscopically pertinent anatomy of the anterolateral and posteromedial bundles of the posterior cruciate ligament.
abstract: BACKGROUND
  The clock-face method to identify the femoral posterior cruciate ligament (PCL) attachment has poor accuracy and reproducibility. Measurements of clinically relevant anatomic structures would provide more useful surgical guidance. The purpose of the present study was to describe the attachments of the anterolateral and posteromedial bundles of the PCL relative to relevant landmarks to assist with arthroscopic anatomic PCL reconstructions.
  
  
  METHODS
  Dissections were performed on twenty nonpaired fresh-frozen cadaveric knees.
  
  
  RESULTS
  The distal articular cartilage margin of the intercondylar notch had a consistent shape conforming to the attachments of the anterolateral and posteromedial bundles. The mean distance (and standard deviation) between the femoral centers of the anterolateral and posteromedial bundles was 12.1 ± 1.3 mm. The distal margins of the anterolateral and posteromedial bundles were a mean of 1.5 ± 0.8 mm and 5.8 ± 1.7 mm proximal to the notch articular cartilage, respectively. On the tibia, the lateral plateau articular cartilage, the medial meniscus attachment, and an osseous ridge ("bundle ridge") separating the anterolateral and posteromedial bundles were important arthroscopic landmarks. The mean distance between the tibial centers of the anterolateral and posteromedial bundles was 8.9 ± 1.2 mm.
  
  
  CONCLUSIONS
  The pertinent landmarks identified during arthroscopic PCL reconstruction consistently marked the borders of the attachments of the anterolateral and posteromedial bundles. To guide femoral tunnel placement, the centers of both bundles should be triangulated relative to the reported landmarks. Furthermore, the distal edge of the femoral anterolateral bundle should be placed adjacent to the articular cartilage, whereas the posteromedial bundle should be centered, on average, 8.6 mm proximal to the cartilage margin, just distal to the medial intercondylar ridge. On the tibia, the PCL tunnel should be placed just anterosuperior to the bundle ridge, with use of the lateral articular cartilage and medial meniscus attachment to guide placement.
  
  
  CONCLUSIONS
  The results of the present study can assist with more anatomic tunnel placement during single and double-bundle PCL reconstructions. The results also suggest that two reconstruction tunnels are needed to reconstruct the broad femoral attachment, whereas one reconstruction tunnel should be investigated further for the compact tibial attachment.
authors.affiliation: Department of BioMedical Engineering, Steadman Philippon Research Institute, Vail, CO, USA.
authors.forename: Colin J
authors.initials: CJ
authors.lastname: Anderson
authors.forename: Connor G
authors.initials: CG
authors.lastname: Ziegler
authors.forename: Coen A
authors.initials: CA
authors.lastname: Wijdicks
authors.forename: Lars
authors.initials: L
authors.lastname: Engebretsen
authors.forename: Robert F
authors.initials: RF
authors.lastname: LaPrade
mesh_terms: D000328:Adult; D001182:Arthroscopy; D002102:Cadaver; D002358:Cartilage, Articular / Q000033:anatomy & histology*; D004210:Dissection; D005269:Femur / Q000033:anatomy & histology; D006801:Humans; D007719:Knee Joint / Q000033:anatomy & histology*; D008592:Menisci, Tibial / Q000033:anatomy & histology; D008875:Middle Aged; D016119:Posterior Cruciate Ligament / Q000033:anatomy & histology* / Q000601:surgery; D015203:Reproducibility of Results; D013977:Tibia / Q000033:anatomy & histology*; D055815:Young Adult