title: Magnetic resonance imaging at different time periods following hamstring harvest for anterior cruciate ligament reconstruction.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the magnetic resonance imaging (MRI) appearance of the hamstring graft harvest site after harvesting the hamstring tendons to reconstruct a torn anterior cruciate ligament (ACL).
  
  
  METHODS
  Case series.
  
  
  METHODS
  We performed MRI on 21 patients who had previously undergone hamstring harvest and ACL reconstruction. Twenty of the patients (7 female and 13 male; mean age, 37 years; range, 16 to 84 years), all volunteers, were selected from a series of 45 ACL reconstructions performed by the senior author during a 20-month period. Another patient, a 32-year-old man, underwent ACL reconstruction elsewhere 32 months before. Both the semitendinosus and gracilis tendons were harvested in all cases. All MRIs were obtained on a 1.5-T magnet and were prospectively evaluated by 2 experienced musculoskeletal radiologists who were blinded to the time interval between graft harvest and MRI.
  
  
  RESULTS
  Two weeks after graft harvest, MRI showed ill-defined intermediate signal on T1-weighted images and increased signal on T2-weighted images, consistent with fluid in the harvest site, with no discernable tendon. At 6 weeks, structures were seen at the level of the superior pole of the patella that had morphology and signal characteristics similar to native tendon. By 3 months, structures with normal morphology and signal characteristics were seen to the level of the joint line, and by 12 months, to the level of 1 to 3 cm above that of the tibial attachment. At 32 months, the tendons appeared on MRI to normalize to a level of 1 to 2 cm above their tibial attachment.
  
  
  CONCLUSIONS
  Following hamstring tendon harvest, MRI demonstrates an apparent regeneration of tendons beginning proximally and extending distally over time.
authors.affiliation: Department of Orthopaedics, Wilford Hall Medical Center, San Antonio, Texas, USA.
authors.forename: D M
authors.initials: DM
authors.lastname: Rispoli
authors.forename: T G
authors.initials: TG
authors.lastname: Sanders
authors.forename: M D
authors.initials: MD
authors.lastname: Miller
authors.forename: W B
authors.initials: WB
authors.lastname: Morrison
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016118:Anterior Cruciate Ligament / Q000473:pathology* / Q000601:surgery*; D000070598:Anterior Cruciate Ligament Injuries; D004487:Edema / Q000175:diagnosis / Q000209:etiology; D005260:Female; D005500:Follow-Up Studies; D006085:Graft Survival; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D013709:Tendon Transfer / Q000009:adverse effects; D013710:Tendons / Q000473:pathology*; D013997:Time Factors