title: Knee rotational stability during pivoting movement is restored after anatomic double-bundle anterior cruciate ligament reconstruction.
abstract: BACKGROUND
  The restoration of knee rotational stability after anatomic double-bundle anterior cruciate ligament (ACL) reconstruction has been demonstrated in the cadaveric model and with passive stress tests on humans but not yet with dynamic functional biomechanical tests performed by human participants.
  
  
  OBJECTIVE
  To prospectively investigate the range of tibial rotation of ACL-deficient and ACL-reconstructed knees during a pivoting task. The authors hypothesized that there would be a significant increase in tibial internal rotation in the ACL-deficient knee compared with the contralateral knee and that the increased rotation would return to normal after anatomic double-bundle ACL reconstruction.
  
  
  METHODS
  Case series; Level of evidence, 4.
  
  
  METHODS
  Ten men with unilateral ACL injury performed a high-demand jump-landing and pivoting task before and after ACL reconstruction with mean follow-up of 11 months. The range of tibial rotation of the injured, reconstructed, and intact knees during the pivoting movement was measured by an optical motion analysis system. Paired t tests were performed to investigate any significant difference between the 2 limbs preoperatively and postoperatively and within the injured limb before and after the surgical treatment. Statistical significance was set at P < .05.
  
  
  RESULTS
  The range of tibial rotation was higher in the ACL-deficient knee (12.6° ± 4.5°) than in the intact knee (7.9° ± 3.1°) preoperatively (P < .05). The increased rotation was reduced in the reconstructed knee (8.9° ± 3.0°) after ACL reconstruction versus the intact knee postoperatively (8.2° ± 2.6°) (P < .05). There was no significant difference in the tibial rotation between the intact knee and the reconstructed knee postoperatively (P > .05).
  
  
  CONCLUSIONS
  As assessed with a dynamic functional pivoting movement, the anatomic double-bundle ACL reconstruction successfully restores knee rotational stability from an impaired level.
authors.affiliation: Department of Orthopaedics and Traumatology, Prince of Wales Hospital, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China.
authors.forename: Mak-Ham
authors.initials: MH
authors.lastname: Lam
authors.forename: Daniel Tik-Pui
authors.initials: DT
authors.lastname: Fong
authors.forename: Patrick Shu-Hang
authors.initials: PS
authors.lastname: Yung
authors.forename: Eric Po-Yan
authors.initials: EP
authors.lastname: Ho
authors.forename: Kwai-Yau
authors.initials: KY
authors.lastname: Fung
authors.forename: Kai-Ming
authors.initials: KM
authors.lastname: Chan
mesh_terms: D000328:Adult; D000070598:Anterior Cruciate Ligament Injuries; D016022:Case-Control Studies; D006801:Humans; D007593:Joint Instability / Q000503:physiopathology; D007718:Knee Injuries / Q000601:surgery*; D007719:Knee Joint / Q000502:physiology*; D008297:Male; D011183:Postoperative Complications / Q000503:physiopathology*; D011446:Prospective Studies; D012399:Rotation; D013977:Tibia / Q000502:physiology*; D055815:Young Adult