title: Magnetic resonance angiography evaluation of the bone tunnel and graft following ACL reconstruction with a hamstring tendon autograft.
abstract: OBJECTIVE
  In this study, magnetic resonance angiography (MRA) was performed in the early phase after anterior cruciate ligament (ACL) reconstruction to analyse the changes in nutrient blood vessels and blood flow to the femoral and tibial tunnels and the intraosseous tendon grafts.
  
  
  METHODS
  The subjects were 30 patients who underwent single-bundle ACL reconstruction with an autogenous hamstring tendon. MRA was performed at 2, 3, and 6 months postoperatively (n = 10 at each time point). The mean overall signal-to-noise ratios (SNRs) in the tunnel regions and in the region of the tendon graft were compared in each femur and tibia.
  
  
  RESULTS
  Blood vessels from arteries reached the femoral and tibial tunnels 2 months postoperatively. The tunnel walls showed high signal intensity, while the intraosseous tendon grafts had lower intensity. SNRs showed significant differences between the femoral and tibial tunnels overall and the intraosseous tendon grafts. At 3 and 6 months postoperatively, the signal intensity of the tunnel walls was decreased significantly, while that of the intraosseous tendon grafts was also decreased, but not significantly. At these times, the SNRs of the femoral and tibial tunnels did not differ significantly, both overall and in the region of the intraosseous tendon grafts.
  
  
  CONCLUSIONS
  Revascularization around the femoral and tibial tunnels occurred at 2 months postoperatively, with blood flow subsequently decreasing over time until 6 months. This revascularization may be involved in bone tendon healing and maturation of the tendon graft within the bone tunnels. Evaluations of revascularization by MRA may show the maturation stage of the graft and guide medical rehabilitation.
  
  
  METHODS
  IV.
authors.affiliation: Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, 465 Kajiicho, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto, 602-8566, Japan.
authors.forename: Ryu
authors.initials: R
authors.lastname: Terauchi
authors.affiliation: Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, 465 Kajiicho, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto, 602-8566, Japan. yarai89046@nike.eonet.ne.jp.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Arai
authors.affiliation: Department of Orthopaedics, Social Insurance Kyoto Hospital, Kyoto, Japan.
authors.forename: Kunio
authors.initials: K
authors.lastname: Hara
authors.affiliation: Department of Orthopaedics, Social Insurance Kyoto Hospital, Kyoto, Japan.
authors.forename: Ginjiro
authors.initials: G
authors.lastname: Minami
authors.affiliation: Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, 465 Kajiicho, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto, 602-8566, Japan.
authors.forename: Shuji
authors.initials: S
authors.lastname: Nakagawa
authors.affiliation: Department of Radiology, Social Insurance Kyoto Hospital, Kyoto, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Takahashi
authors.affiliation: Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, 465 Kajiicho, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto, 602-8566, Japan.
authors.forename: Kazuya
authors.initials: K
authors.lastname: Ikoma
authors.affiliation: Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, 465 Kajiicho, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto, 602-8566, Japan.
authors.forename: Keiichiro
authors.initials: K
authors.lastname: Ueshima
authors.affiliation: Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, 465 Kajiicho, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto, 602-8566, Japan.
authors.forename: Toshiharu
authors.initials: T
authors.lastname: Shirai
authors.affiliation: Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, 465 Kajiicho, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto, 602-8566, Japan.
authors.forename: Hiroyoshi
authors.initials: H
authors.lastname: Fujiwara
authors.affiliation: Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, 465 Kajiicho, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto, 602-8566, Japan.
authors.forename: Toshikazu
authors.initials: T
authors.lastname: Kubo
mesh_terms: D000328:Adult; D016118:Anterior Cruciate Ligament / Q000601:surgery; D000070598:Anterior Cruciate Ligament Injuries; D059549:Anterior Cruciate Ligament Reconstruction / Q000379:methods*; D064592:Autografts / Q000098:blood supply*; D005260:Female; D005269:Femur / Q000098:blood supply* / Q000473:pathology / Q000601:surgery; D006801:Humans; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged; D013710:Tendons / Q000098:blood supply* / Q000637:transplantation; D013977:Tibia / Q000098:blood supply* / Q000473:pathology / Q000601:surgery; D014182:Transplantation, Autologous; D055815:Young Adult
keywords: Anterior cruciate ligament (ACL) reconstruction; Blood supply; Magnetic resonance angiography (MRA); Revascularization