title: Meniscal allograft transplantation. Part 1: systematic review of graft biology, graft shrinkage, graft extrusion, graft sizing, and graft fixation.
abstract: OBJECTIVE
  To provide a systematic review of the literature regarding five topics in meniscal allograft transplantation: graft biology, shrinkage, extrusion, sizing, and fixation.
  
  
  METHODS
  A systematic literature search was conducted using the PubMed (MEDLINE), ScienceDirect, and EBSCO-CINAHL databases. Articles were classified only in one topic, but information contained could be reported into other topics. Information was classified according to type of study (animal, in vitro human, and in vivo human) and level of evidence (for in vivo human studies).
  
  
  RESULTS
  Sixty-two studies were finally included: 30 biology, 3 graft shrinkage, 11 graft extrusion, 17 graft size, and 6 graft fixation (some studies were categorized in more than one topic). These studies corresponded to 22 animal studies, 22 in vitro human studies, and 23 in vivo human studies (7 level II, 10 level III, and 6 level IV).
  
  
  CONCLUSIONS
  The principal conclusions were as follows: (a) Donor cells decrease after MAT and grafts are repopulated with host cells form synovium; (b) graft preservation alters collagen network (deep freezing) and causes cell apoptosis with loss of viable cells (cryopreservation); (c) graft shrinkage occurs mainly in lyophilized and gamma-irradiated grafts (less with cryopreservation); (d) graft extrusion is common but has no clinical/functional implications; (e) overall, MRI is not superior to plain radiograph for graft sizing; (f) graft width size matching is more important than length size matching; (g) height appears to be the most important factor influencing meniscal size; (h) bone fixation better restores contact mechanics than suture fixation, but there are no differences for pullout strength or functional results; and (i) suture fixation has more risk of graft extrusion compared to bone fixation.
  
  
  METHODS
  Systematic review of level II-IV studies, Level IV.
authors.affiliation: Department of Orthopaedics, Sports Medicine Division, Henry Ford Health System, William Clay Ford Center for Athletic Medicine, 6525 Second Avenue, Detroit, MI, 48202, USA.
authors.forename: Gonzalo
authors.initials: G
authors.lastname: Samitier
authors.forename: Eduard
authors.initials: E
authors.lastname: Alentorn-Geli
authors.forename: Dean C
authors.initials: DC
authors.lastname: Taylor
authors.forename: Brian
authors.initials: B
authors.lastname: Rill
authors.forename: Terrence
authors.initials: T
authors.lastname: Lock
authors.forename: Vasilius
authors.initials: V
authors.lastname: Moutzouros
authors.forename: Patricia
authors.initials: P
authors.lastname: Kolowich
mesh_terms: D064591:Allografts; D000818:Animals; D006085:Graft Survival; D006801:Humans; D007718:Knee Injuries / Q000503:physiopathology / Q000601:surgery*; D008279:Magnetic Resonance Imaging; D008592:Menisci, Tibial / Q000503:physiopathology* / Q000601:surgery* / Q000637:transplantation; D011475:Prosthesis Failure; D000070600:Tibial Meniscus Injuries; D014184:Transplantation, Homologous; D014945:Wound Healing