title: Functional outcomes of Y-graft double-bundle and single-bundle anterior cruciate ligament reconstruction of the knee.
abstract: OBJECTIVE
  The purpose of this study was to compare the functional outcome, ligament laxity, and tibial tunnel enlargement between 3-tunnel double-bundle (DB) anterior cruciate ligament (ACL) and single-bundle (SB) ACL reconstruction.
  
  
  METHODS
  This retrospective study identified primary arthroscopic ACL reconstruction from July 2006 to July 2008. The cohort consisted of 50 knees in 49 patients, comprising 26 knees with SB ACL reconstruction and 24 with DB ACL reconstruction. Semitendinosus autograft was used in SB ACL reconstruction, and semitendinosus and gracilis grafts were used in DB ACL reconstruction. Both groups received the same rehabilitation protocol postoperatively. The evaluations included functional assessment, ligament laxity, and radiographs of the knee. Functional assessments included a pain score, the Lysholm functional score, the Tegner activity score, and the grade on the International Knee Documentation Committee knee examination form. Ligament laxity was measured by the anterior drawer test, Lachman test, pivot-shift test, and KT-1000 arthrometer (MEDmetric, San Diego, CA) testing. It was graded as 0 for no laxity, 0 to 5 mm for mild laxity, 5 to 10 mm for moderate laxity, and 10 to 15 mm for severe laxity. Radiographs of the knee were used for the evaluation of bony appearance, alignment of the knee, joint space narrowing, and measurement of the tibial tunnel.
  
  
  RESULTS
  Significant improvements in knee function and ligament laxity were noted after surgery in both groups. However, no statistical differences in functional scores and ligament laxity were noted between the 2 groups (P = .275 and P = .413, respectively). A mild increase in laxity was noted in 3 cases (14%) in the DB ACL reconstruction group and 3 cases (13%) in the SB ACL reconstruction group. A moderate increase in laxity was noted in 2 cases (9%) in the SB ACL reconstruction group and none in the DB ACL reconstruction group. Radiographic evaluations showed no statistical difference between the 2 groups (P = .114).
  
  
  CONCLUSIONS
  Both 3-tunnel Y-graft DB ACL reconstruction and SB ACL reconstruction significantly improved the function and stability of the knee after surgery.
  
  
  METHODS
  Level IV, therapeutic case series.
authors.affiliation: Department of Orthopaedic Surgery, Jhong Jheng Orthopedic Hospital, Kaohsiung, Taiwan.
authors.forename: Mui-Leng
authors.initials: ML
authors.lastname: Lao
authors.forename: Jen-Hung
authors.initials: JH
authors.lastname: Chen
authors.forename: Ching-Jen
authors.initials: CJ
authors.lastname: Wang
authors.forename: Ka-Kit
authors.initials: KK
authors.lastname: Siu
mesh_terms: D000293:Adolescent; D000328:Adult; D016118:Anterior Cruciate Ligament / Q000503:physiopathology / Q000601:surgery; D059549:Anterior Cruciate Ligament Reconstruction / Q000379:methods* / Q000534:rehabilitation; D001182:Arthroscopy / Q000379:methods; D005260:Female; D006801:Humans; D007593:Joint Instability / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery; D007719:Knee Joint / Q000000981:diagnostic imaging / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D010027:Osteotomy / Q000379:methods; D011859:Radiography; D012189:Retrospective Studies; D013710:Tendons / Q000637:transplantation; D013848:Thigh; D013977:Tibia / Q000601:surgery*; D014182:Transplantation, Autologous; D016896:Treatment Outcome; D055815:Young Adult