title: Is Remnant Preservation Truly Beneficial to Anterior Cruciate Ligament Reconstruction Healing? Clinical and Magnetic Resonance Imaging Evaluations of Remnant-Preserved Reconstruction.
abstract: BACKGROUND
  Remnant-preserved anterior cruciate ligament (ACL) reconstruction was introduced to improve clinical outcomes and biological healing. However, the effects of remnant preservation and the influence of the delay from injury until reconstruction on the outcomes of this technique are still uncertain. Purpose/Hypothesis: The purposes of this study were to evaluate whether remnant preservation improved the clinical outcomes and graft incorporation of ACL reconstruction and to examine the influence of the delay between ACL injury and reconstruction on the usefulness of remnant preservation. We hypothesized that remnant preservation improves clinical results and accelerates graft incorporation and that its effect is dependent on the delay between ACL injury and reconstruction.
  
  
  METHODS
  Cohort study; Level of evidence, 2.
  
  
  METHODS
  A total of 151 consecutive patients who underwent double-bundle ACL reconstruction using a semitendinosus graft were enrolled in this study: 74 knees underwent ACL reconstruction without a remnant (or the remnant was <25% of the intra-articular portion of the graft; NR group), while 77 knees underwent ACL reconstruction with remnant preservation (RP group). These were divided into 4 subgroups based on the time from injury to surgery: phase 1 was <3 weeks (n = 24), phase 2 was 3 to less than 8 weeks (n = 70), phase 3 was 8 to 20 weeks (n = 32), and phase 4 was >20 weeks (n = 25). Clinical measurements, including KT-1000 arthrometer side-to-side anterior tibial translation measurements, were assessed at 3, 6, 12, and 24 months after reconstruction. Magnetic resonance imaging evaluations of graft maturation and graft-tunnel integration of the anteromedial and posterolateral bundles were assessed at 3, 6, and 12 months after reconstruction.
  
  
  RESULTS
  There was no difference in side-to-side anterior tibial translation between the NR and RP groups. There was also no difference in graft maturation between the 2 groups. Furthermore, the time from ACL injury until reconstruction did not affect graft maturation, except in the case of very long delays before reconstruction (phase 4). Graft-tunnel integration was significantly increased in both groups in a time-dependent manner. However, there was no difference between the NR and RP groups.
  
  
  CONCLUSIONS
  Remnant preservation did not improve knee stability at 2 years after ACL reconstruction. Furthermore, remnant preservation did not accelerate graft incorporation, especially during the acute and subacute injury phases.
authors.affiliation: Department of Orthopaedic Surgery, Hirosaki University Graduate School of Medicine, Hirosaki, Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Naraoka
authors.affiliation: Department of Orthopaedic Surgery, Hirosaki University Graduate School of Medicine, Hirosaki, Japan.
authors.forename: Yuka
authors.initials: Y
authors.lastname: Kimura
authors.affiliation: Department of Orthopaedic Surgery, Hirosaki University Graduate School of Medicine, Hirosaki, Japan.
authors.forename: Eiichi
authors.initials: E
authors.lastname: Tsuda
authors.affiliation: Department of Orthopaedic Surgery, Hirosaki University Graduate School of Medicine, Hirosaki, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Yamamoto
authors.affiliation: Department of Orthopaedic Surgery, Hirosaki University Graduate School of Medicine, Hirosaki, Japan.
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Ishibashi
mesh_terms: D000293:Adolescent; D000328:Adult; D016118:Anterior Cruciate Ligament / Q000601:surgery*; D000070598:Anterior Cruciate Ligament Injuries / Q000601:surgery*; D059549:Anterior Cruciate Ligament Reconstruction / Q000379:methods*; D002648:Child; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007593:Joint Instability / Q000601:surgery; D007719:Knee Joint / Q000601:surgery*; D008279:Magnetic Resonance Imaging; D008297:Male; D013977:Tibia / Q000601:surgery; D019737:Transplants; D014945:Wound Healing; D055815:Young Adult
keywords: MRI; anterior cruciate ligament; double-bundle reconstruction; remnant tissue