title: Reliability of a navigation system for intra-operative evaluation of antero-posterior knee joint laxity.
abstract: BACKGROUND
  The purpose of this study was to investigate about the reliability of measuring antero-posterior laxity within-subjects for in-vivo studies using a navigation system.
  
  
  METHODS
  The analysis was performed by enroling 60 patients undergoing anterior cruciate ligament ACL reconstruction, and assessing AP laxity during the Lachman and drawer tests.
  
  
  RESULTS
  For the navigation system standard deviation for intra-trial measures was 0.7 mm, thus the intra-trial repeatability coefficient was 2.2 mm; standard deviation for intra-trial measure was 1.2 mm, while the reference inter-trial repeatability coefficient between expert surgeons was 3.4 mm.
  
  
  CONCLUSIONS
  In conclusion, this study suggests that KIN-Nav may represent a new method to measure and document AP laxity intra-operatively with improved accuracy and test the effect of surgical treatment in-vivo with higher sensitivity than in the past and this study quantify its reliability for within-subjects studies performed by a single expert surgeon.
authors.affiliation: Istituto Ortopedico Rizzoli, Laboratorio di Biomeccanica, via di Barbiano, 1/10, Bologna BO 40136, Italy. n.lopomo@biomec.ior.it
authors.forename: Nicola
authors.initials: N
authors.lastname: Lopomo
authors.forename: Simone
authors.initials: S
authors.lastname: Bignozzi
authors.forename: Sandra
authors.initials: S
authors.lastname: Martelli
authors.forename: Stefano
authors.initials: S
authors.lastname: Zaffagnini
authors.forename: Francesco
authors.initials: F
authors.lastname: Iacono
authors.forename: Andrea
authors.initials: A
authors.lastname: Visani
authors.forename: Maurilio
authors.initials: M
authors.lastname: Marcacci
mesh_terms: D000293:Adolescent; D000328:Adult; D016118:Anterior Cruciate Ligament / Q000503:physiopathology / Q000601:surgery*; D000070598:Anterior Cruciate Ligament Injuries; D004867:Equipment Design; D005260:Female; D006801:Humans; D007593:Joint Instability / Q000175:diagnosis / Q000503:physiopathology*; D007719:Knee Joint / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D019651:Plastic Surgery Procedures / Q000295:instrumentation* / Q000379:methods; D015203:Reproducibility of Results; D012371:Robotics / Q000295:instrumentation* / Q000379:methods; D025321:Surgery, Computer-Assisted / Q000295:instrumentation* / Q000379:methods; D013673:Technology Assessment, Biomedical