title: Pain following double-bundle anterior cruciate ligament reconstruction: correlation with morphological graft findings and dynamic contrast-enhanced MRI.
abstract: OBJECTIVE
  To determine the relationship between knee pain following anterior cruciate ligament (ACL) graft placement with morphological graft findings and dynamic contrast enhancement as assessed at MRI.
  
  
  METHODS
  Following institutional review board approval, 37 consecutive patients with double-bundle ACL reconstruction were enrolled. Thirteen patients had pain and 24 were asymptomatic. Imaging was performed using a 1.5 T MRI machine an average of 7.6 months after surgery. Graft-related (increase signal intensity, abnormal orientation, discontinuity, cystic degeneration, anterior translation of lateral tibia, arthrofibrosis), and non-graft related causes of knee pain (meniscal tear, cartilage injury, loose bodies, and synovitis) were evaluated. During dynamic contrast enhancement analysis, peak enhancement (ePeak) was calculated by placing a region of interest at the osteoligamentous interface of each bundle. Student's t-test was used for continuous variables analysis and chi-square or Fisher's exact test was used for categorical variables analysis.
  
  
  RESULTS
  There was no difference between symptomatic and asymptomatic patients regarding morphological graft-related or non-graft-related causes of knee pain. For dynamic contrast enhancement analysis, symptomatic patients had significantly lower ePeak values than asymptomatic patients in the anteromedial (p = 0.008) and posterolateral (p = 0.001) bundles or when using the higher ePeak value in either bundle (p = 0.003).
  
  
  CONCLUSIONS
  Morphological ACL graft findings as assessed at MRI could not be used to distinguish between symptomatic and asymptomatic patients. However, lower ePeak values had a significant association with knee pain. This may indicate poor neovascularization of the graft, potentially leading to graft failure.
authors: Department of Medical Imaging and Intervention, Chang Gung Memorial Hospital, Keelung and Chang Gung University, Taiwan.
authors: Y-C
authors: YC
authors: Lin
authors: Department of Radiology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
authors: J N
authors: JN
authors: Mhuircheartaigh
authors: Department of Medical Imaging and Intervention, Chang Gung Memorial Hospital, Linkou and Chang Gung University, Taiwan.
authors: Y-C
authors: YC
authors: Cheung
authors: Department of Medical Imaging and Intervention, Chang Gung Memorial Hospital, Linkou and Chang Gung University, Taiwan.
authors: Y-H
authors: YH
authors: Juan
authors: Department of Orthopedic Surgery, Division of Sports Medicine, Chang Gung Memorial Hospital, Linkou and Chang Gung University, Taiwan.
authors: C-H
authors: CH
authors: Chiu
authors: Department of Orthopedic Surgery, Division of Sports Medicine, Chang Gung Memorial Hospital, Linkou and Chang Gung University, Taiwan. Electronic address: yeh.wenlin@msa.hinet.net.
authors: W-L
authors: WL
authors: Yeh
authors: Department of Radiology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
authors: J S
authors: JS
authors: Wu
mesh_terms: D000293:Adolescent; D000328:Adult; D059549:Anterior Cruciate Ligament Reconstruction; D001182:Arthroscopy; D003287:Contrast Media; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement; D010149:Postoperative Pain / Q000175:diagnosis*
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA