title: Lateral Tibial Posterior Slope Is Increased in Patients With Early Graft Failure After Anterior Cruciate Ligament Reconstruction.
abstract: BACKGROUND
  The lateral tibial posterior slope (LTPS) has been reported in multiple studies to correlate with an increased risk for native anterior cruciate ligament (ACL) tearing. To date, no study has examined the effect of an increased LTPS as measured on magnetic resonance imaging (MRI) on the likelihood of ACL graft failure.
  
  
  OBJECTIVE
  An increased LTPS as measured on MRI would correlate with an increased risk for ACL graft failure.
  
  
  METHODS
  Case-control study; Level of evidence, 3.
  
  
  METHODS
  Fifty-eight patients were initially identified who experienced graft failure after primary ACL reconstruction and underwent revision between 1998 and 2009. Exclusion criteria were clinical follow-up of less than 4 years, graft failure occurring greater than 2 years after primary surgery, skeletal immaturity, deep infection, lack of available preoperative MRI, and history of trauma to the proximal tibia. This left 35 patients with early (within 2 years) failure of primary ACL reconstruction. These patients were matched to 35 control participants who had undergone ACL reconstruction with a minimum of 4 years of clinical follow-up and no evidence of graft failure. Patients were matched by age, sex, date of primary surgery, and graft type. The LTPS was then determined on MRI in a blinded fashion.
  
  
  RESULTS
  The mean time to failure in patients in the study group was 1 year (range, 0.6-1.4 years). The mean follow-up of those in the matched control group was 6.9 years (range, 4.0-13.9 years). The mean LTPS in the early ACL failure group was found to be 8.4°, which was significantly larger than that in the control group at 6.5° (P = .012). The odds ratio for graft failure considering a 2° increase in the LTPS was 1.6 (95% CI, 1.1-2.2) and continued to increase to 2.4 (95% CI, 1.2-5.0) and 3.8 (95% CI, 1.3-11.3) with 4° and 6° increases in the LTPS, respectively. No significant association was identified between graft type and graft failure.
  
  
  CONCLUSIONS
  An increased LTPS is associated with an increased risk for early ACL graft failure, regardless of graft type. Orthopaedic surgeons should consider measuring the LTPS as part of the preoperative assessment of ACL-injured patients.
authors: Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota, USA.
authors: Joshua J
authors: JJ
authors: Christensen
authors: Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota, USA.
authors: Aaron J
authors: AJ
authors: Krych
authors: Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota, USA.
authors: William M
authors: WM
authors: Engasser
authors: MoRe Foundation, Monica Hospital, Antwerp, Belgium.
authors: Matthias K
authors: MK
authors: Vanhees
authors: Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA.
authors: Mark S
authors: MS
authors: Collins
authors: Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota, USA dahm.diane@mayo.edu.
authors: Diane L
authors: DL
authors: Dahm
mesh_terms: D000328:Adult; D016118:Anterior Cruciate Ligament / Q000601:surgery; D000070598:Anterior Cruciate Ligament Injuries; D059549:Anterior Cruciate Ligament Reconstruction / Q000009:adverse effects*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D007718:Knee Injuries / Q000175:diagnosis / Q000601:surgery*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications; D012086:Reoperation; D012189:Retrospective Studies; D012307:Risk Factors; D013977:Tibia; D055815:Young Adult
keywords: ACL injury; ACL reconstruction; geometry; revision; tibial plateau