title: Various factors contribute to graft extrusion in lateral meniscus allograft transplantation.
abstract: OBJECTIVE
  Lateral meniscus allograft transplantation (LMAT) is a feasible surgical option for young meniscus-deficient patients. Although several studies have explored the factors that contribute to graft extrusion, they have not been fully elucidated. The aim of this study was to determine the various factors that contribute to graft extrusion.
  
  
  METHODS
  Patients with knees that had received LMAT using a keyhole technique (n = 87 knees in 82 patients) were reviewed. The median age of these patients was 22 years (range 19-54 years), and the median postprocedural follow-up interval was 5 days (range 1-136 days). Twelve magnetic resonance imaging (MRI) measurement parameters (axial and coronal location of the bone block) that could potentially influence graft extrusion were evaluated, along with absolute graft extrusion and relative percentage of extrusion (RPE).
  
  
  RESULTS
  A significant correlation was found between 8 of the 12 MRI measurement parameters and both the absolute extrusion and RPE (r = 0.241-0.438, p < 0.05). The absolute middle distance and depth of the bone block were independent predictors of the absolute extrusion (β = 0.30 and 0.15, respectively; p < 0.05), and the relative middle distance and relative bone-block elevation were found to be predictors of RPE (β = 2.29 and 1.44, respectively; p < 0.05).
  
  
  CONCLUSIONS
  The rate of graft extrusions after LMAT was high in this study. Both the coronal and axial locations of the bone block were found to influence graft extrusion in LMAT. Therefore, correct positioning of the bone block, including in both the axial and coronal planes, is essential to minimize graft extrusion. Future studies need to investigate the long-term clinical outcome and longevity of extruded menisci after transplantation.
  
  
  METHODS
  Therapeutic case series, Level IV.
authors.affiliation: Department of Radiology, The Armed Forces Capital Hospital, 177 Saemael-ro, Bundang-gu, Sungnam, 13574, Republic of Korea. lsyrad@gmail.com.
authors.forename: Sang Yub
authors.initials: SY
authors.lastname: Lee
authors.affiliation: Department of Radiology, The Armed Forces Capital Hospital, 177 Saemael-ro, Bundang-gu, Sungnam, 13574, Republic of Korea.
authors.forename: Jaegu
authors.initials: J
authors.lastname: Yoon
authors.affiliation: Department of Radiology, The Armed Forces Capital Hospital, 177 Saemael-ro, Bundang-gu, Sungnam, 13574, Republic of Korea.
authors.forename: Young Seo
authors.initials: YS
authors.lastname: Cho
authors.affiliation: Department of Radiology, The Armed Forces Capital Hospital, 177 Saemael-ro, Bundang-gu, Sungnam, 13574, Republic of Korea.
authors.forename: Rak Chae
authors.initials: RC
authors.lastname: Son
authors.affiliation: Department of Radiology, The Armed Forces Capital Hospital, 177 Saemael-ro, Bundang-gu, Sungnam, 13574, Republic of Korea.
authors.forename: Sung Kwan
authors.initials: SK
authors.lastname: Kim
authors.affiliation: Department of Radiology, The Armed Forces Capital Hospital, 177 Saemael-ro, Bundang-gu, Sungnam, 13574, Republic of Korea.
authors.forename: Sang Hyuk
authors.initials: SH
authors.lastname: Ahn
authors.affiliation: Department of Radiology, The Armed Forces Capital Hospital, 177 Saemael-ro, Bundang-gu, Sungnam, 13574, Republic of Korea.
authors.forename: Hyeon-Kyeong
authors.initials: HK
authors.lastname: Lee
mesh_terms: D000328:Adult; D064591:Allografts; D002357:Cartilage Diseases / Q000601:surgery*; D005260:Female; D051445:Fibrocartilage / Q000637:transplantation*; D005548:Foreign-Body Migration / Q000000981:diagnostic imaging*; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging*; D008279:Magnetic Resonance Imaging; D008297:Male; D008592:Menisci, Tibial / Q000601:surgery*; D008875:Middle Aged; D011183:Postoperative Complications / Q000000981:diagnostic imaging*; D012189:Retrospective Studies; D014184:Transplantation, Homologous; D055815:Young Adult
keywords: Extrusion; Magnetic resonance imaging; Meniscus; Meniscus allograft transplantation