title: A systematic review of anterior cruciate ligament reconstruction with autograft compared with allograft.
abstract: BACKGROUND
  Anterior cruciate ligament reconstruction can be performed with use of either autograft or allograft tissue. It is currently unclear if the outcomes of these two methods differ significantly. This systematic review and meta-analysis investigated whether the short-term clinical outcomes of anterior cruciate reconstruction with allograft were significantly different from those with autograft.
  
  
  METHODS
  A computerized search of the electronic databases MEDLINE and EMBASE was conducted. Only therapeutic studies with a prospective or retrospective comparative design were considered for inclusion in the present investigation. Two reviewers independently assessed the methodological quality and extracted relevant data from each included study. If a study failed the qualitative assessment and statistical tests of homogeneity, it was excluded from the meta-analysis. Furthermore, a study was withdrawn from the meta-analysis of a particular outcome if that outcome was not studied or was not reported adequately. A Mantel-Haenszel analysis utilizing a random-effects model allowed for pooling of results according to graft source while accounting for the number of subjects in individual studies.
  
  
  RESULTS
  Nine studies were determined to be appropriate for the systematic review. Eight studies compared bone-patellar tendon-bone grafts, and one study compared quadruple-stranded hamstring grafts. Five studies were prospective comparative studies, and four were retrospective comparative studies. One study, which investigated allografts that underwent a unique sterilization process, demonstrated an allograft failure rate of 45% (thirty-eight of eighty-five). That study failed the qualitative assessment and statistical tests of homogeneity and consequently was excluded from the meta-analysis. When the outcomes from the remaining studies were pooled according to graft source, the meta-analyses of the Lysholm score, instrumented laxity measurements, and the clinical failure rate estimated mean differences and odds ratios that were not significant. These findings were robust during the sensitivity analysis, which varied the included studies or variables on the basis of graft type, instrumented laxity cut-off value, secondary sterilization technique, duration of follow-up, mean patient age, and study methodology.
  
  
  CONCLUSIONS
  In general, the short-term clinical outcomes of anterior cruciate reconstruction with allograft were not significantly different from those with autograft. However, it is important to note that none of these nonrandomized studies stratified outcomes according to age or utilized multivariable modeling to mathematically control for age (or any other possible confounder, such as activity level, that is not equally distributed in the two treatment groups). Understanding these limitations of the best available evidence, the surgeon may incorporate the results of the present systematic review into the informed-consent and shared-decision-making process in order to individualize optimum patient care.
authors.affiliation: Department of Orthopaedics and Rehabilitation, Vanderbilt University Medical Center, Nashville, TN 37232, USA. james.carey@vanderbilt.edu
authors.forename: James L
authors.initials: JL
authors.lastname: Carey
authors.forename: Warren R
authors.initials: WR
authors.lastname: Dunn
authors.forename: Diane L
authors.initials: DL
authors.lastname: Dahm
authors.forename: Scott L
authors.initials: SL
authors.lastname: Zeger
authors.forename: Kurt P
authors.initials: KP
authors.lastname: Spindler
mesh_terms: D016118:Anterior Cruciate Ligament / Q000601:surgery*; D000070598:Anterior Cruciate Ligament Injuries; D006801:Humans; D019637:Orthopedic Procedures / Q000379:methods*; D019651:Plastic Surgery Procedures; D012421:Rupture; D014182:Transplantation, Autologous; D014184:Transplantation, Homologous