title: A randomized controlled trial comparing bone mineral density changes of three different ACL reconstruction techniques.
abstract: BACKGROUND
  This study aimed to compare the changes in bone mineral density (BMD) of three different ACL reconstruction (ACLR) techniques and its association with early clinical and functional outcomes.
  
  
  METHODS
  Sixty-two male adult patients undergoing primary ACLR were prospectively parallel randomized to bone-patellar tendon-bone graft (BPTB), single-bundle (HT-SB) or double-bundle (HT-DB) hamstring graft. BMD (primary outcome) at the proximal tibia, distal femur, femoral neck and trochanteric region was measured blindly at day 1, 3 months, 5 months and 1 year after surgery. KT-1000, Lysholm, IKDC, one-leg hop test and Lachman test were performed blindly at baseline and 1 year post-reconstruction.
  
  
  RESULTS
  There was a significant bone loss at the injured knee and hip at 3 and 5 months which was reversible at the knee, but not at the hip, at 1 year post-operation. There was a significant improvement of early clinical and functional outcomes at 1 year. No significant differences in bone loss was detected among different surgical techniques, except BMD loss at the femoral neck, though a trend of greater BMD loss in the HT-SB group at 5 months after reconstruction was observed. There was a significant positive correlation between BMD at the distal femur and the single-leg hop distance at 1 year.
  
  
  CONCLUSIONS
  In conclusion, the three surgical techniques were similar in transient bone loss at the knee region, irreversible bone loss at the hip, early clinical and functional outcomes up to 1 year post-reconstruction. BMD at the distal femur was positively associated with the single-leg hop distance at 1 year post-reconstruction.
authors.affiliation: Department of Orthopaedics and Traumatology, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong Special Administrative Region, China. pauline@ort.cuhk.edu.hk
authors.forename: Pauline Po Yee
authors.initials: PP
authors.lastname: Lui
authors.forename: Ying Ying
authors.initials: YY
authors.lastname: Cheng
authors.forename: Shu Hang
authors.initials: SH
authors.lastname: Yung
authors.forename: Aaron See Long
authors.initials: AS
authors.lastname: Hung
authors.forename: Kai Ming
authors.initials: KM
authors.lastname: Chan
mesh_terms: D000328:Adult; D000070598:Anterior Cruciate Ligament Injuries; D059549:Anterior Cruciate Ligament Reconstruction; D015519:Bone Density; D050376:Bone-Patellar Tendon-Bone Grafting; D015331:Cohort Studies; D006801:Humans; D007718:Knee Injuries / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D016059:Range of Motion, Articular; D020127:Recovery of Function; D013710:Tendons / Q000637:transplantation*; D016896:Treatment Outcome; D055815:Young Adult