title: Increased Risk of Revision After Anterior Cruciate Ligament Reconstruction With Bone-Patellar Tendon-Bone Allografts Compared With Autografts.
abstract: BACKGROUND
  The use of allograft tissue for anterior cruciate ligament reconstruction (ACLR) remains controversial.
  
  
  OBJECTIVE
  To compare the risk of aseptic revision between bone-patellar tendon-bone (BPTB) autografts and BPTB allografts.
  
  
  METHODS
  Cohort study; Level of evidence, 2.
  
  
  METHODS
  A retrospective cohort study of prospectively collected data was conducted using the Kaiser Permanente ACLR Registry. A cohort of patients who underwent primary unilateral ACLR with BPTB autografts and BPTB allografts was identified. Aseptic revision was the endpoint. The type of graft and allograft processing method (nonprocessed, <1.8-Mrad, and ≥1.8-Mrad irradiation) were the exposures of interest evaluated. Age (≤21 and ≥22 years) was evaluated as an effect modifier. Analyses were adjusted for age, sex, and race. Kaplan-Meier curves and Cox proportional hazards models were employed. Hazard ratios (HRs) and 95% CIs are provided.
  
  
  RESULTS
  The BPTB cohort consisted of 5586 patients: 3783 (67.7%) were male, 2359 (42.2%) were white, 1029 (18.4%) had allografts (nonprocessed: 155; <1.8 Mrad: 525; ≥1.8 Mrad: 288), and 4557 (81.6%) had autografts. The median age was 34.9 years (interquartile range [IQR], 25.4-44.0) for allograft cases and 22.0 years (IQR, 17.6-30.0) for autograft cases. The estimated cumulative revision rate at 2 years was 4.1% (95% CI, 2.9%-5.9%) for allografts and 1.7% (95% CI, 1.3%-2.2%) for autografts. BPTB allografts had a significantly higher adjusted risk of revision than BPTB autografts (HR, 4.54; 95% CI, 3.03-6.79; P < .001). This higher risk of revision was consistent with all allograft processing methods when compared with autografts and was also consistently higher in patients with allografts regardless of age.
  
  
  CONCLUSIONS
  When BPTB allograft tissue was used for ACLR, an overall 4.54 times adjusted higher risk of revision was observed compared with surgery performed with a BPTB autograft. Whether the tissue was irradiated with either high- or low-dose radiation, chemically processed, or not processed at all made little difference in the risk of revision. The differences in the revision risk were also consistent in younger and older patients. Surgeons and patients should be aware of the increased risk of revision when a BPTB allograft is used for ACLR.
authors.affiliation: Kaiser Permanente, San Diego, California, USA.
authors.forename: Gregory B
authors.initials: GB
authors.lastname: Maletis
authors.affiliation: Kaiser Permanente, San Diego, California, USA.
authors.forename: Jason
authors.initials: J
authors.lastname: Chen
authors.affiliation: University of South Australia, Adelaide, Australia.
authors.forename: Maria C S
authors.initials: MCS
authors.lastname: Inacio
authors.affiliation: Kaiser Permanente, San Diego, California, USA.
authors.forename: Rebecca M
authors.initials: RM
authors.lastname: Love
authors.affiliation: Kaiser Permanente Sand Canyon, Irvine, California, USA.
authors.forename: Tadashi T
authors.initials: TT
authors.lastname: Funahashi
mesh_terms: D016118:Anterior Cruciate Ligament / Q000601:surgery; D000070598:Anterior Cruciate Ligament Injuries / Q000601:surgery*; D050376:Bone-Patellar Tendon-Bone Grafting / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D017847:Patellar Ligament / Q000601:surgery; D016016:Proportional Hazards Models; D012042:Registries; D012086:Reoperation; D012189:Retrospective Studies; D012307:Risk Factors; D014182:Transplantation, Autologous; D014184:Transplantation, Homologous; D055815:Young Adult
keywords: allografts; anterior cruciate ligament; autografts; knee ligaments