title: A prospectively randomized double-blind study on the effect of initial graft tension on knee stability after anterior cruciate ligament reconstruction.
abstract: BACKGROUND
  No consensus exists on the amount of tension that should be applied to anterior cruciate ligament grafts to best facilitate graft incorporation and re-create normal knee mechanics.
  
  
  OBJECTIVE
  Differences in initial graft tension will affect postoperative knee stability.
  
  
  METHODS
  Prospective, randomized, double-blind clinical trial.
  
  
  METHODS
  Forty-nine patients undergoing bone-patellar tendon-bone autograft anterior cruciate ligament reconstruction by a single surgeon were randomized into high-tension (n = 27) and low-tension (n = 22) groups. Grafts were set at 90 N or 45 N. Arthrometric measurements (KT-1000 arthrometer manual maximum) of anterior tibial displacement and knee range of motion were made before surgery and at 1 week and an average of 20 months after surgery. Knee outcome scores were collected before and after surgery, and a single-leg hop test was also performed at final follow-up.
  
  
  RESULTS
  After anterior cruciate ligament reconstruction, anterior tibial displacement was significantly greater in the patients in the low-tension group (P < .05). The side-to-side difference in anterior tibial displacement in the high-tension and low-tension groups was 1.1 +/- 1.7 mm versus 2.4 +/- 2.4 mm 1 week after surgery and 2.2 +/- 1.6 mm versus 3.0 +/- 2.2 mm at follow-up. Five patients had abnormal anterior tibial displacement (>5 mm side-to-side difference), and all were in the low-tension group (P <.05). Knee outcome scores improved with surgery (P <.01), with similar results for low-tension and high-tension groups. Hop test deficits were not different between groups.
  
  
  CONCLUSIONS
  Initial graft tension affects the restoration of knee stability. A graft tension of 45 N was not sufficient for restoring knee stability.
authors.affiliation: Nicholas Institute of Sports Medicine and Athletic Trauma, Lenox Hill Hospital, New York, New York 10021, USA.
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Nicholas
authors.forename: Michael J
authors.initials: MJ
authors.lastname: D'Amato
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Mullaney
authors.forename: Timothy F
authors.initials: TF
authors.lastname: Tyler
authors.forename: Kirsten
authors.initials: K
authors.lastname: Kolstad
authors.forename: Malachy P
authors.initials: MP
authors.lastname: McHugh
mesh_terms: D000328:Adult; D016118:Anterior Cruciate Ligament / Q000503:physiopathology / Q000601:surgery*; D000070598:Anterior Cruciate Ligament Injuries; D001182:Arthroscopy; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007593:Joint Instability / Q000209:etiology / Q000517:prevention & control*; D007719:Knee Joint / Q000503:physiopathology / Q000601:surgery; D008297:Male; D011446:Prospective Studies; D016059:Range of Motion, Articular / Q000502:physiology; D013709:Tendon Transfer / Q000009:adverse effects / Q000379:methods*; D013710:Tendons / Q000503:physiopathology / Q000601:surgery; D013718:Tensile Strength / Q000502:physiology