title: In vivo posterior cruciate ligament elongation in running activity after anatomic and non-anatomic anterior cruciate ligament reconstruction.
abstract: OBJECTIVE
  The goals of this study were to (1) investigate the in vivo elongation behaviour of the posterior cruciate ligament (PCL) during running in the uninjured knee and (2) evaluate changes in PCL elongation during running after anatomic or non-anatomic anterior cruciate ligament (ACL) reconstruction.
  
  
  METHODS
  Seventeen unilateral ACL-injured subjects were recruited after undergoing anatomic (n = 9) or non-anatomic (n = 8) ACL reconstruction. Bilateral high-resolution CT scans were obtained to produce 3D models. Anterolateral (AL) and posteromedial (PM) bundles insertion sites of the PCL were identified on the 3D CT scan reconstructions. Dynamic knee function was assessed during running using a dynamic stereo X-ray (DSX) system. The lengths of the AL and PM bundles were estimated from late swing through mid-stance. The contralateral knees served as normal controls.
  
  
  RESULTS
  Control knees demonstrated a slight decrease in AL bundle and a significant decrease in PM bundle length following foot strike. Length and elongation patterns of the both bundles of the PCL in the anatomic ACL reconstruction group were similar to the controls. However, the change in dynamic PCL length was significantly greater in the non-anatomic group than in the anatomic reconstruction group after foot strike (p < 0.05).
  
  
  CONCLUSIONS
  The AL bundle length decreased slightly, and the PM bundle length significantly decreased after foot strike during running in uninjured knees. Anatomic ACL reconstruction maintained normal PCL elongation patterns more effectively than non-anatomic ACL reconstruction during high-demand, functional loading. These results support the use of anatomic ACL reconstruction to achieve normal knee function in high-demand activities.
  
  
  METHODS
  Case-control study, Level III.
authors.affiliation: Department of Orthopedic Surgery, Beijing Jishuitan Hospital, 31 Xinjiekou Dongjie St., Beijing, 100035, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Tang
authors.affiliation: Department of Mechanical Engineering, University of Washington, Seattle, WA, USA.
authors.forename: Eric
authors.initials: E
authors.lastname: Thorhauer
authors.affiliation: Orthopedic Research Laboratories, University of Pittsburgh, 3820 South Water St., Pittsburgh, PA, 15203, USA.
authors.forename: Karl
authors.initials: K
authors.lastname: Bowman
authors.affiliation: Orthopedic Research Laboratories, University of Pittsburgh, 3820 South Water St., Pittsburgh, PA, 15203, USA.
authors.forename: Freddie H
authors.initials: FH
authors.lastname: Fu
authors.affiliation: Orthopedic Research Laboratories, University of Pittsburgh, 3820 South Water St., Pittsburgh, PA, 15203, USA. tashman@pitt.edu.
authors.forename: Scott
authors.initials: S
authors.lastname: Tashman
mesh_terms: D000328:Adult; D000368:Aged; D059549:Anterior Cruciate Ligament Reconstruction / Q000379:methods*; D001696:Biomechanical Phenomena / Q000502:physiology; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D008875:Middle Aged; D016119:Posterior Cruciate Ligament / Q000000981:diagnostic imaging* / Q000502:physiology; D012420:Running / Q000502:physiology*; D014057:Tomography, X-Ray Computed; D055815:Young Adult
keywords: Anterior cruciate ligament (ACL); Anterior cruciate ligament reconstruction; In vivo knee kinematics; Posterior cruciate ligament (PCL); Soft tissue biomechanics