title: Current use of navigation system in ACL surgery: a historical review.
abstract: OBJECTIVE
  The present review aims to analyse the available literature regarding the use of navigation systems in ACL reconstructive surgery underling the evolution during the years.
  
  
  METHODS
  A research of indexed scientific papers was performed on PubMed and Cochrane Library database. The research was performed in December 2015 with no publication year restriction. Only English-written papers and related to the terms ACL, NAVIGATION, CAOS and CAS were considered. Two reviewers independently selected only those manuscripts that presented at least the application of navigation system for ACL reconstructive surgery.
  
  
  RESULTS
  One hundred and forty-six of 394 articles were finally selected. In this analysis, it was possible to review the main uses of navigation system in ACL surgery including tunnel positioning for primary and revision surgery and kinematic assessment of knee laxity before and after different surgical procedures. In the early years, until 2006, navigation system was mainly used to improve tunnel positioning, but since the last decade, this tool has been principally used for kinematics evaluation. Increased accuracy of tunnel placement was observed using navigation surgery, especially, regarding femoral, 42 of 146 articles used navigation to guide tunnel positioning. During the following years, 82 of 146 articles have used navigation system to evaluate intraoperative knee kinematic. In particular, the importance of controlling rotatory laxity to achieve better surgical outcomes has been underlined.
  
  
  CONCLUSIONS
  Several applications have been described and despite the contribution of navigation systems, its potential uses and theoretical advantages, there are still controversies about its clinical benefit. The present papers summarize the most relevant studies that have used navigation system in ACL reconstruction. In particular, the analysis identified four main applications of the navigation systems during ACL reconstructive surgery have been identified: (1) technical assistance for tunnel placement; (2) improvement in knowledge of the kinematic behaviour of ACL and other structures; (3) comparison of effectiveness of different surgical techniques in controlling laxities; (4) navigation system performance to improve the outcomes of ACL reconstruction and cost-effectiveness.
  
  
  METHODS
  IV.
authors.affiliation: Laboratorio di Biomeccanica e Innovazione Tecnologica, Istituto Ortopedico Rizzoli, Bologna, BO, Italy. stefano.zaffagnini@unibo.it.|Dipartimento di Scienze Biomediche e Neuromotorie - DIBINEM, Università di Bologna, Bologna, BO, Italy. stefano.zaffagnini@unibo.it.|Clinica Ortopedica e Traumatologica I, Istituto Ortopedico Rizzoli, Bologna, BO, Italy. stefano.zaffagnini@unibo.it.|Dipartimento Rizzoli Sicilia, Istituto Ortopedico Rizzoli, Bagheria, PA, Italy. stefano.zaffagnini@unibo.it.
authors.forename: S
authors.identifier: http://orcid.org/0000-0002-2941-1407
authors.initials: S
authors.lastname: Zaffagnini
authors.affiliation: Hospital Las Higueras, Talcahuano, Concepción, Región del Bío Bío, Chile.
authors.forename: F
authors.initials: F
authors.lastname: Urrizola
authors.affiliation: Laboratorio di Biomeccanica e Innovazione Tecnologica, Istituto Ortopedico Rizzoli, Bologna, BO, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Signorelli
authors.affiliation: Laboratorio di Biomeccanica e Innovazione Tecnologica, Istituto Ortopedico Rizzoli, Bologna, BO, Italy.|Clinica Ortopedica e Traumatologica I, Istituto Ortopedico Rizzoli, Bologna, BO, Italy.|Dipartimento Rizzoli Sicilia, Istituto Ortopedico Rizzoli, Bagheria, PA, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Grassi
authors.affiliation: Laboratorio di Biomeccanica e Innovazione Tecnologica, Istituto Ortopedico Rizzoli, Bologna, BO, Italy.|Clinica Ortopedica e Traumatologica I, Istituto Ortopedico Rizzoli, Bologna, BO, Italy.
authors.forename: T Roberti
authors.initials: TR
authors.lastname: Di Sarsina
authors.affiliation: Laboratorio di Biomeccanica e Innovazione Tecnologica, Istituto Ortopedico Rizzoli, Bologna, BO, Italy.
authors.forename: G A
authors.initials: GA
authors.lastname: Lucidi
authors.affiliation: Laboratorio di Biomeccanica e Innovazione Tecnologica, Istituto Ortopedico Rizzoli, Bologna, BO, Italy.|Dipartimento di Scienze Biomediche e Neuromotorie - DIBINEM, Università di Bologna, Bologna, BO, Italy.|Clinica Ortopedica e Traumatologica I, Istituto Ortopedico Rizzoli, Bologna, BO, Italy.|Dipartimento Rizzoli Sicilia, Istituto Ortopedico Rizzoli, Bagheria, PA, Italy.
authors.forename: G M
authors.initials: GM
authors.lastname: Marcheggiani Muccioli
authors.affiliation: Laboratorio di Biomeccanica e Innovazione Tecnologica, Istituto Ortopedico Rizzoli, Bologna, BO, Italy.|Dipartimento di Scienze Biomediche e Neuromotorie - DIBINEM, Università di Bologna, Bologna, BO, Italy.|Clinica Ortopedica e Traumatologica I, Istituto Ortopedico Rizzoli, Bologna, BO, Italy.
authors.forename: T
authors.initials: T
authors.lastname: Bonanzinga
authors.affiliation: Laboratorio di Biomeccanica e Innovazione Tecnologica, Istituto Ortopedico Rizzoli, Bologna, BO, Italy.|Dipartimento di Scienze Biomediche e Neuromotorie - DIBINEM, Università di Bologna, Bologna, BO, Italy.|Clinica Ortopedica e Traumatologica I, Istituto Ortopedico Rizzoli, Bologna, BO, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Marcacci
mesh_terms: D016118:Anterior Cruciate Ligament / Q000601:surgery*; D001696:Biomechanical Phenomena; D005269:Femur / Q000601:surgery; D049674:History, 21st Century; D006801:Humans; D007719:Knee Joint / Q000601:surgery; D012086:Reoperation; D025321:Surgery, Computer-Assisted / Q000266:history* / Q000379:methods*
keywords: ACL; Computer-assisted surgery (CAS); Kinematic; Navigation system; Tunnel placement