title: The Effect of Postoperative KT-1000 Arthrometer Score on Long-Term Outcome After Anterior Cruciate Ligament Reconstruction.
abstract: BACKGROUND
  Many long-term studies have looked at outcomes after anterior cruciate ligament reconstruction (ACLR), but none have correlated long-term outcomes with postoperative laxity greater than 5 mm. It has been stated previously that more than 5 mm of postoperative graft laxity constituted a procedural failure.
  
  
  OBJECTIVE
  To directly compare tight grafts (<3 mm) and loose grafts (>5 mm) to determine the effect of graft laxity, as measured by KT-1000 arthrometer, after ACLR on long-term clinical outcomes.
  
  
  METHODS
  Cohort study; Level of evidence, 2.
  
  
  METHODS
  The study included 171 consecutive patients who had undergone transtibial bone-patellar tendon-bone ACLR between 1992 and 1998. At 6, 12, and 24 months postoperatively (the immediate postoperative period), patients were evaluated. Group A included patients with a maximal side-to-side (STS) difference in the immediate postoperative period of less than 3 mm (tight grafts), and group B included patients with a maximal STS difference of greater than 5 mm (loose grafts). Any patient with a history of ipsilateral or contralateral ACLR or ACL injury, meniscectomy, or cartilage restoration was excluded. Patients were prospectively followed to long-term follow-up, when a telephone interview was conducted regarding knee function and to document Lysholm, Tegner, Knee injury and Osteoarthritis Outcome Score (KOOS), and International Knee Documentation Committee (IKDC) subjective outcome scores.
  
  
  RESULTS
  Eighty-seven patients met inclusion criteria: 66 tight grafts (group A) and 21 loose grafts (group B). The mean ± SD time to follow-up was 16.3 ± 1.5 years in group A (n = 46) and 16.8 ± 1.3 years in group B (n = 15). Tegner ( P = .77), Lysholm ( P = .85), KOOS ( P = .96), and IKDC ( P = .42) were found to have no statistically significant difference between groups at long-term follow-up. Both Tegner and Lysholm scores significantly improved in tight and loose grafts in the immediate postoperative period as well as at long-term follow-up compared with preoperatively. There were 2 ACL revisions in group A and none in group B. Eleven of 46 patients (24%) in group A required subsequent procedures versus 1 of 15 patients (6.7%) in group B ( P = .146).
  
  
  CONCLUSIONS
  Postoperative laxity of greater than 5 mm STS difference as measured by KT-1000 arthrometer does not appear to place patients at a worse clinical outcome at long-term follow-up, nor does it lead to significantly more subsequent procedures. In addition, transtibial ACLR can provide excellent clinical results at long-term follow-up.
authors.affiliation: Department of Orthopaedic Surgery, Lenox Hill Hospital, New York, New York, USA.
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Goodwillie
authors.affiliation: Department of Orthopaedic Surgery, Northwell Health Long Island Jewish Medical Center, New Hyde Park, New York, USA.
authors.forename: Sarav S
authors.initials: SS
authors.lastname: Shah
authors.affiliation: Nicholas Institute of Sports Medicine and Athletic Trauma, Department of Orthopaedic Surgery, Lenox Hill Hospital, New York, New York, USA.
authors.forename: Malachy P
authors.initials: MP
authors.lastname: McHugh
authors.affiliation: Nicholas Institute of Sports Medicine and Athletic Trauma, Department of Orthopaedic Surgery, Lenox Hill Hospital, New York, New York, USA.
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Nicholas
mesh_terms: D000328:Adult; D016118:Anterior Cruciate Ligament / Q000601:surgery*; D059549:Anterior Cruciate Ligament Reconstruction / Q000379:methods*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007593:Joint Instability / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D011184:Postoperative Period; D016896:Treatment Outcome; D055815:Young Adult
keywords: anterior cruciate ligament (ACL); outcomes; reconstruction; tension