title: Characterization of cruciate ligament impingement: the influence of femoral or tibial tunnel positioning at different degrees of knee flexion.
abstract: OBJECTIVE
  We aimed to analyze how different positions of the tibial and femoral tunnels when used for anterior cruciate ligament (ACL) reconstruction affect relations with the posterior cruciate ligament (PCL) at different degrees of knee flexion. Information gained from this study may be helpful in determining optimal placement of the graft in ACL reconstructive surgery.
  
  
  METHODS
  We divided 10 cadaveric knees into 2 groups of 5 and had either their femoral or tibial ACL insertion detached. For each specimen, 16 different positions were reproduced during ACL reconstruction based on a combination of 4 different tunnels in the tibia for group A (anterior-medial, anterior-lateral, posterior-medial, and posterior-lateral) and 4 in the femur for group B (anterior-proximal, anterior-distal, posterior-proximal, and posterior-distal) with 4° of knee flexion for each (0°, 45°, 90°, and 135°). We performed a magnetic resonance imaging (MRI) study for each configuration and analyzed the cruciate ligament positioning.
  
  
  RESULTS
  We identified 3 different situations: no contact between cruciate ligaments, contact without deformity, and contact with deformity. In group A, the degree of flexion (P = .003) and ligament insertion positioned in the posterior quadrants (P < .05) were statistically significant for the presence of ACL impingement. Ligament contact with deformity was identified in 18 (22.5%) configurations, mostly when the knee was flexed 45° and 90° and the ACL was in the posterior quadrants. For group B, "contact with deformity" was identified in 23 MR images, mostly (12 cases) with the graft position being in the anterior-distal configuration, but it was not significant for the occurrence of cruciate impingement.
  
  
  CONCLUSIONS
  Impingement with ligament deformity is greater when the graft is fixed at the posterior quadrants of the tibial footprint, regardless of the degree of knee flexion. Although quite common, the ligament position in the femoral footprint was not a primary cause of ACL impingement with deformity.
  
  
  CONCLUSIONS
  This study helps identify positions of the tibial or femoral tunnels during ACL reconstruction to avoid impingement between cruciate ligaments.
authors: Departamento de Ortopedia e Traumatologia da Escola Paulista de Medicina/UNIFESP, São Paulo, SP, Brazil. mcastur@yahoo.com
authors: Diego Costa
authors: DC
authors: Astur
authors: Ciro Veronese
authors: CV
authors: Santos
authors: Vinicius
authors: V
authors: Aleluia
authors: Nelson
authors: N
authors: Astur Neto
authors: Gustavo Gonçalves
authors: GG
authors: Arliani
authors: Camila Cohen
authors: CC
authors: Kaleka
authors: Abdalla
authors: A
authors: Skaf
authors: Moises
authors: M
authors: Cohen
mesh_terms: D000328:Adult; D016118:Anterior Cruciate Ligament / Q000601:surgery*; D059549:Anterior Cruciate Ligament Reconstruction / Q000009:adverse effects / Q000379:methods*; D002102:Cadaver; D006801:Humans; D007592:Joint Diseases / Q000175:diagnosis* / Q000209:etiology; D007719:Knee Joint / Q000601:surgery*; D008279:Magnetic Resonance Imaging; D016119:Posterior Cruciate Ligament / Q000601:surgery*; D013977:Tibia / Q000601:surgery*