title: Revision surgery in anterior cruciate ligament reconstruction: a cohort study of 17,682 patients from the Swedish National Knee Ligament Register.
abstract: OBJECTIVE
  To investigate the association between surgical variables and the risk of revision surgery after ACL reconstruction in the Swedish National Knee Ligament Register.
  
  
  METHODS
  This cohort study was based on data from the Swedish National Knee Ligament Register. Patients who underwent primary single-bundle ACL reconstruction with hamstring tendon were included. Follow-up started with primary ACL reconstruction and ended with ACL revision surgery or on 31 December, 2014, whichever occurred first. Details on surgical technique were collected using an online questionnaire. All group comparisons were made in relation to an "anatomic" reference group, comprised of essential AARSC items, defined as utilization of accessory medial portal drilling, anatomic tunnel placement, visualization of insertion sites and pertinent landmarks. Study end-point was revision surgery.
  
  
  RESULTS
  A total of 108 surgeons (61.7%) replied to the questionnaire. A total of 17,682 patients were included [n = 10,013 males (56.6%) and 7669 females (43.4%)]. The overall revision rate was 3.1%. Older age as well as cartilage injury evident at index surgery was associated with a decreased risk of revision surgery. The group using transtibial drilling and non-anatomic bone tunnel placement was associated with a lower risk of revision surgery [HR 0.694 (95% CI 0.490-0.984); P = 0.041] compared with the anatomic reference group. The anatomic reference group showed no difference in risk of revision surgery compared with the transtibial drilling groups with partial anatomic [HR 0.759 (95% CI 0.548-1.051), n.s.] and anatomic tunnel placement [HR 0.944 (95% CI 0.718-1.241), n.s.]. The anatomic reference group showed a decreased risk of revision surgery compared with the transportal drilling group with anatomic placement [HR 1.310 (95% CI 1.047-1.640); P = 0.018].
  
  
  CONCLUSIONS
  Non-anatomic bone tunnel placement via transtibial drilling resulted in the lowest risk of revision surgery after ACL reconstruction. The risk of revision surgery increased when using transportal drilling. Performing anatomic ACL reconstruction utilizing eight selected essential items from the AARSC lowered the risk of revision surgery associated with transportal drilling and anatomic bone tunnel placement. Detailed knowledge of surgical technique using the AARSC predicts the risk of ACL revision surgery.
  
  
  METHODS
  III.
authors.affiliation: Department of Orthopedics, Sahlgrenska University Hospital, 431 80, Mölndal, Sweden. neel@desai.nu.|Department of Orthopedics, Institute of Clinical Sciences, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden. neel@desai.nu.
authors.forename: Neel
authors.initials: N
authors.lastname: Desai
authors.affiliation: Department of Orthopedics, Institute of Clinical Sciences, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.|Vårdcentralen Gripen, Karlstad, Sweden.|Primary Care Research Unit, County Council of Värmland, Karlstad, Sweden.
authors.forename: Daniel
authors.initials: D
authors.lastname: Andernord
authors.affiliation: Department of Orthopedics, Sahlgrenska University Hospital, 431 80, Mölndal, Sweden.|Department of Orthopedics, Institute of Clinical Sciences, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
authors.forename: David
authors.initials: D
authors.lastname: Sundemo
authors.affiliation: Department of Orthopaedic Surgery, Mayo Clinic, Rochester, MN, USA.
authors.forename: Eduard
authors.initials: E
authors.lastname: Alentorn-Geli
authors.affiliation: Department of Orthopedic Surgery, University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: Volker
authors.initials: V
authors.lastname: Musahl
authors.affiliation: Department of Orthopedic Surgery, University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: Freddie
authors.initials: F
authors.lastname: Fu
authors.affiliation: Stockholm Sports Trauma Research Center, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Magnus
authors.initials: M
authors.lastname: Forssblad
authors.affiliation: Department of Orthopedics, Sahlgrenska University Hospital, 431 80, Mölndal, Sweden.|Department of Orthopedics, Institute of Clinical Sciences, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
authors.forename: Kristian
authors.initials: K
authors.lastname: Samuelsson
mesh_terms: D000293:Adolescent; D000328:Adult; D016118:Anterior Cruciate Ligament / Q000601:surgery*; D000070598:Anterior Cruciate Ligament Injuries / Q000601:surgery*; D059549:Anterior Cruciate Ligament Reconstruction / Q000379:methods / Q000706:statistics & numerical data*; D015331:Cohort Studies; D005260:Female; D005269:Femur / Q000601:surgery; D006801:Humans; D007719:Knee Joint / Q000601:surgery; D008297:Male; D008875:Middle Aged; D012086:Reoperation / Q000706:statistics & numerical data*; D012306:Risk; D013548:Sweden; D013977:Tibia / Q000601:surgery; D055815:Young Adult
keywords: Anatomic; Anterior cruciate ligament; Drilling; Reconstruction; Register; Revision