title: Injury patterns in patients presenting with a recurrent anterior cruciate ligament tear following primary reconstruction.
abstract: BACKGROUND
  An anterior cruciate ligament (ACL) graft rupture or a primary ACL injury in the contralateral knee is one of the greatest concerns of patients following primary anterior cruciate ligament reconstruction (ACLR). Our study describes the epidemiology and presence of concomitant meniscal injuries of patients with a graft rupture following primary ACLR or a primary rupture of the contralateral ACL following primary ACLR of the ipsilateral knee.
  
  
  METHODS
  We reviewed the medical records of 42 patients who underwent a second ACLR. ACLR was performed using the ipsilateral semitendinosus and gracilis autograft. Variables extracted included the presence of concomitant MM and LM injuries intra-operatively, the patients' level of intensity of sport (light, moderate, strenuous), duration of rehabilitation and mechanism of injury (contact, non-contact).
  
  
  RESULTS
  Twenty-four (57.1%) patients had graft rupture of a previously reconstructed ACL of which 20 (83.3%) were male and 18 (42.9%) patients had a primary ACL tear of the contralateral knee following ACLR of the ipsilateral knee of which 18 (100%) were male. Patient who sustained a graft rupture were younger (29.5 vs. 31.9 years), had a higher body mass index (BMI) (26.42 vs. 25.10 kg/m(2)) and had a longer time before re-injury (6.18 vs. 4.94 years). Concomitant meniscal injury rates were comparable in both groups and the medial meniscus was injured more often.
  
  
  CONCLUSIONS
  This study describes the demographics of 2(nd) ACL injuries in the Asian population. Additional studies that investigate the differences in knee anatomy of Asians and Caucasians and their impact on ACL injuries should be performed.
authors.affiliation: Yong Loo Lin School of Medicine, National University of Singapore (NUS), Singapore ;
authors.forename: Bryan T H
authors.initials: BT
authors.lastname: Koh
authors.affiliation: Yong Loo Lin School of Medicine, National University of Singapore (NUS), Singapore ;
authors.forename: Andrew A
authors.initials: AA
authors.lastname: Sayampanathan
authors.affiliation: Singapore General Hospital, Academia, Singapore.
authors.forename: Hamid Rahmatullah
authors.initials: HR
authors.lastname: Bin Abd Razak
authors.affiliation: Singapore General Hospital, Academia, Singapore.
authors.forename: Hwei Chi
authors.initials: HC
authors.lastname: Chong
authors.affiliation: Singapore General Hospital, Academia, Singapore.
authors.forename: Hwee-Chye Andrew
authors.initials: HC
authors.lastname: Tan
keywords: Anterior cruciate ligament (ACL); anterior cruciate ligament reconstruction (ACLR); contralateral tear; epidemiology; graft rupture; meniscus; reconstruction