title: Long-standing increased bone turnover at the fixation points after anterior cruciate ligament reconstruction: a positron emission tomography (PET) study of 8 patients.
abstract: BACKGROUND
  A secure incorporation of the graft in a bone tunnel is a prerequisite for successful anterior cruciate ligament reconstruction. In this cross-sectional pilot study, we studied the healing process with positron emission tomography (PET) scanning.
  
  
  METHODS
  8 young patients underwent an anterior cruciate ligament reconstruction with a bonepatellar tendon-bone graft (BTB, n = 4) or a quadruple semitendinosus and gracilis graft (ST/G, n = 4). Regional bone turnover was quantified with an 18F-fluoride PET scan in each patient 1 day, 3 weeks, 7 months, or 22 months after surgery.
  
  
  RESULTS
  The highest activity level was found 3 weeks after surgery, but the activity at the femoral fixation points was markedly increased even after 7 months. The bone turnover was almost normalized 22 months after the operation.
  
  
  CONCLUSIONS
  It would take at least 7 months until an anterior cruciate ligament graft, fixed with an interference screw, is completely incorporated. This finding is important for postoperative rehabilitation. Furthermore, PET is a feasible tool when studying new ways of fixing soft tissue to bone.
authors.affiliation: Department of Nuclear Medicine, University Hospital, Uppsala, Sweden. jens.sorensen@uppsala.imanet.se
authors.forename: Jens
authors.initials: J
authors.lastname: Sörensen
authors.forename: Karl
authors.initials: K
authors.lastname: Michaelsson
authors.forename: Håvard
authors.initials: H
authors.lastname: Strand
authors.forename: Stefan
authors.initials: S
authors.lastname: Sundelin
authors.forename: Hans
authors.initials: H
authors.lastname: Rahme
mesh_terms: D000328:Adult; D016118:Anterior Cruciate Ligament / Q000000981:diagnostic imaging / Q000601:surgery*; D000070598:Anterior Cruciate Ligament Injuries; D050376:Bone-Patellar Tendon-Bone Grafting / Q000534:rehabilitation; D003430:Cross-Sectional Studies; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging / Q000378:metabolism*; D006801:Humans; D008297:Male; D010329:Patella / Q000000981:diagnostic imaging / Q000378:metabolism*; D010865:Pilot Projects; D049268:Positron-Emission Tomography; D013710:Tendons / Q000637:transplantation; D013977:Tibia / Q000000981:diagnostic imaging / Q000378:metabolism*; D013997:Time Factors; D014945:Wound Healing