title: Serial magnetic resonance imaging evaluation of the patellar tendon after posterior cruciate ligament reconstruction.
abstract: OBJECTIVE
  Our purpose was to prospectively analyze serial changes in magnetic resonance imaging (MRI) signal of the bone-patellar tendon-bone autograft when used for posterior cruciate ligament (PCL) reconstruction and to retrospectively determine at mid-term follow-up the relationship between MRI graft appearance and clinical stability in patients who have undergone arthroscopic PCL reconstruction with a bone-patellar tendon-bone autograft.
  
  
  METHODS
  One prospective serial blinded study and 1 retrospective blinded study.
  
  
  METHODS
  The first part of the study focused on MRI scans obtained at 3, 6, 9, and 12 months postoperatively in a case series of 10 consecutive patients who underwent arthroscopically assisted PCL reconstruction (group A), and of 10 patients who underwent combined ACL-PCL arthroscopic reconstruction (group B). For the second part of the study, MRI scans were obtained in a retrospective series of 10 patients at mid-term follow-up after PCL arthroscopic reconstruction (group C). Signal intensity of 3 zones, corresponding to the proximal, middle, and distal intra-articular graft zones, was evaluated according to the Howell et al. classification. Fiber continuity assessment was performed using a modified Kühne et al. score. The signal intensity of the 3 zones was independently scored. Knee stability was clinically and instrumentally graded according to the IKDC evaluation form (group 4). A multivariance analysis and grouped t test were used for statistical evaluation.
  
  
  RESULTS
  In group A, the average MRI evaluation score was 7.65 +/- 1.6 at 3 months, 3.8 +/- 0.6 at 6 months, 4.75 +/- 1 at 9 months and 6.25 +/- 1.2 at 1 year. The portion of graft exiting the femoral tunnel exhibited increased signal and faster maturation than the tibial tunnel. In group B (combined ACL-PCL reconstruction), the graft showed slower graft healing with an average MRI score of 4.85 +/- 0.7 at 3 months, 1.9 +/- 0.7 at 6 months, 3.9 +/- 0.9 at 9 months, and 5.3 +/- 1.1 at 1 year. At 1 year follow-up, there was no correlation between MRI appearance and stability in group A, even with MRI findings of fiber continuity. However, at long-term evaluation (group C), a strict correlation between MRI appearance and achieved stability was found.
  
  
  CONCLUSIONS
  The patellar tendon when used for PCL reconstruction requires more than 1 year to achieve a low-signal intensity over its entire course, and the distal zone near the tibial tunnel shows a slower healing process. MRI graft assessment is useful only 1 year or more following PCL reconstruction.
authors.affiliation: Rome University of Motor Sciences, Department of Diagnostic Radiology, San Pietro Hospital FBF, Rome, Italy. ppm.las@iol.it
authors.forename: Pier Paolo
authors.initials: PP
authors.lastname: Mariani
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Margheritini
authors.forename: Gianluca
authors.initials: G
authors.lastname: Camillieri
authors.forename: Alberto
authors.initials: A
authors.lastname: Bellelli
mesh_terms: D000293:Adolescent; D000328:Adult; D001182:Arthroscopy / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007718:Knee Injuries / Q000473:pathology* / Q000503:physiopathology / Q000601:surgery*; D008279:Magnetic Resonance Imaging; D008297:Male; D016119:Posterior Cruciate Ligament / Q000293:injuries / Q000473:pathology* / Q000503:physiopathology / Q000601:surgery*; D011446:Prospective Studies; D012189:Retrospective Studies; D013710:Tendons / Q000637:transplantation*; D013997:Time Factors; D014945:Wound Healing