title: Lower risk of revision with patellar tendon autografts compared with hamstring autografts: a registry study based on 45,998 primary ACL reconstructions in Scandinavia.
abstract: BACKGROUND
  A number of studies have found comparable results after anterior cruciate ligament (ACL) reconstruction with patellar tendon autografts and hamstring autografts; however, few studies have been large enough to reveal differences in risk of revision with regard to clinical and demographic factors.
  
  
  OBJECTIVE
  To present the distribution of grafts for ACL reconstruction based on data in the Scandinavian ACL registries and to compare the risk of revision between patellar tendon autografts and hamstring autografts. Potential associations with other clinical and demographic factors were also explored.
  
  
  METHODS
  Cohort study; Level of evidence, 2.
  
  
  METHODS
  A total of 45,998 primary ACL reconstructions, including 6736 patellar tendon autografts and 38,666 hamstring autografts, were identified in the Scandinavian ACL registries. The overall median follow-up time was 3 years (range, 0-8 years). To compare the risk of revision between groups of patients, univariate Kaplan-Meier analysis (with log-rank test) and the Cox proportional hazard regression model were applied. The hazard rate ratio with 95% CI was reported as a measure of effect.
  
  
  RESULTS
  Patellar tendon and hamstring autografts were used in 14.6% and 84.1% of the patients, respectively. The remaining patients received allografts, direct sutures, or other graft types (1.3%). The primary ACL injury occurred during soccer, team handball, or alpine activities in 67.5% of the patients in the patellar tendon group and 66.2% in the hamstring group. A total of 156 patients in the patellar tendon group and 1042 patients in the hamstring group underwent revision. The overall risk of revision was significantly lower in the patellar tendon group versus the hamstring group (hazard rate ratio = 0.63; 95% CI, 0.53-0.74), and it decreased with increasing age at surgery, although not strictly linearly. The lower risk of revision in the patellar tendon group was consistently observed across subgroups of patient sex, age, and concomitant cartilage injury (P > .05, test for interaction) but seemed to be slightly more pronounced for patients injured during certain pivoting activities (soccer, team handball, and alpine activities) compared with other activities (hazard rate ratio = 0.57 vs 0.81; P = .058, test for interaction).
  
  
  CONCLUSIONS
  The majority of primary ACL reconstructions in Scandinavia are performed with hamstring autografts. Results from the present large prospective study show that patients receiving patellar tendon autografts have a statistically significantly lower risk of revision compared with patients receiving hamstring autografts.
authors.affiliation: Orthopaedic Research Center, Trondheim University Hospital, Trondheim, Norway Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway tone.gifstad@ntnu.no.
authors.forename: Tone
authors.initials: T
authors.lastname: Gifstad
authors.affiliation: Orthopaedic Research Center, Trondheim University Hospital, Trondheim, Norway Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway.
authors.forename: Olav A
authors.initials: OA
authors.lastname: Foss
authors.affiliation: Orthopaedic Center, Oslo University Hospital and Faculty of Medicine, University of Oslo, Oslo, Norway.
authors.forename: Lars
authors.initials: L
authors.lastname: Engebretsen
authors.affiliation: Division of Sportstraumatology, Department of Orthopaedics, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Martin
authors.initials: M
authors.lastname: Lind
authors.affiliation: Capio Artro Clinic AB and Stockholm Sports Trauma Research Center, Stockholm, Sweden.
authors.forename: Magnus
authors.initials: M
authors.lastname: Forssblad
authors.affiliation: Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway.
authors.forename: Grethe
authors.initials: G
authors.lastname: Albrektsen
authors.affiliation: Orthopaedic Research Center, Trondheim University Hospital, Trondheim, Norway Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway.
authors.forename: Jon Olav
authors.initials: JO
authors.lastname: Drogset
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D016118:Anterior Cruciate Ligament / Q000601:surgery; D000070598:Anterior Cruciate Ligament Injuries; D059549:Anterior Cruciate Ligament Reconstruction / Q000379:methods*; D001265:Athletic Injuries / Q000601:surgery; D064592:Autografts; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D017847:Patellar Ligament / Q000637:transplantation*; D063868:Patient Outcome Assessment; D016016:Proportional Hazards Models; D012042:Registries; D012086:Reoperation; D012537:Scandinavian and Nordic Countries / Q000453:epidemiology; D012737:Sex Factors; D013710:Tendons / Q000637:transplantation*
keywords: anterior cruciate ligament reconstruction; graft; registry; revision