title: FEMORAL ROLL BACK IN TOTAL KNEE ARTHROPLASTY: COMPARISON BETWEEN PROSTHESES THAT PRESERVE AND SACRIFICE THE POSTERIOR CRUCIATE LIGAMENT.
abstract: To compare the rollback of the contact point between the femoral component and the tibial polyethylene as the knee is flexed, in two types of total knee arthroplasty: one that sacrifices and the other that preserves the posterior cruciate ligament (PCL).
  
  
  METHODS
  Under fluoroscopy, 36 knees from 32 patients who underwent total knee arthroplasty were evaluated. Using lateral images, the contact points between the femur and the tibial polyethylene with the knee in complete extension and at 90° of flexion were measured, thereby measuring the percentage rollback of the femur in arthroplasties in which the PCL was sacrificed and in those in which it was preserved.
  
  
  RESULTS
  The mean percentage rollback of the femur was 13.24% in the cases in which the PCL was sacrificed and 5.75% in the cases in which it was preserved. The difference between these measurements was statistically significant (p = 0.026615).
  
  
  CONCLUSIONS
  In total knee arthroplasty, sacrificing the PCL increased the rollback of the contact point between the femur and tibia as the knee was flexed up to 90°.
authors.affiliation: PhD from the Federal University of São Paulo (UNIFESP). Adjunct Professor in the Department of the Locomotor System, School of Medicine, Federal University of Minas Gerais; Member of the Knee Group at Hospital Madre Teresa, Belo Horizonte, Brazil.
authors.forename: Lúcio Honório de
authors.initials: LH
authors.lastname: Carvalho Júnior
authors.affiliation: Member of the Knee Group at Hospital Madre Teresa, Belo Horizonte, Brazil.
authors.forename: Luiz Fernando
authors.initials: LF
authors.lastname: Machado Soares
authors.affiliation: Member of the Knee Group at Hospital Madre Teresa, Belo Horizonte, Brazil.
authors.forename: Matheus Braga Jacques
authors.initials: MB
authors.lastname: Gonçalves
authors.affiliation: Physician undergoing Specialization training at Hospital Madre Teresa, Belo Horizonte, Brazil.
authors.forename: Leonardo Lanziotti
authors.initials: LL
authors.lastname: Costa
authors.affiliation: Physician undergoing Specialization training at Hospital Madre Teresa, Belo Horizonte, Brazil.
authors.forename: Lincoln Paiva
authors.initials: LP
authors.lastname: Costa
authors.affiliation: Physician undergoing Specialization training at Hospital Madre Teresa, Belo Horizonte, Brazil.
authors.forename: Rodrigo Rosa
authors.initials: RR
authors.lastname: Lessa
authors.affiliation: Physician undergoing Specialization training at Hospital Madre Teresa, Belo Horizonte, Brazil.
authors.forename: Marcelo Lobo
authors.initials: ML
authors.lastname: Pereira
keywords: Arthroplasty; Articular; Biomechanics; Knee; Range of Motion; Replacement