title: Radiological outcomes of pinless navigation in total knee arthroplasty: a randomized controlled trial.
abstract: OBJECTIVE
  This study aimed to investigate the accuracy of pinless navigation (BrainLAB(®) VectorVision(®) Knee 2.5 Navigation System) as an intra-operative alignment guide in total knee arthroplasty (TKA). The authors hypothesized that pinless navigation would reduce the proportion of outliers in conventional TKA, without a significant increase in the duration of surgery.
  
  
  METHODS
  Between 2011 and 2012, 100 patients scheduled for a unilateral primary TKA were randomized into two groups: pinless navigation and conventional surgery. All TKAs were performed with the surgical aim of achieving neutral coronal alignment with a 180° mechanical axis. The primary outcomes of this study were post-operative radiographic assessment of lower limb alignment using hip-knee-ankle angle (HKA) and components placement using coronal femoral-component angle (CFA) and coronal tibia-component angle (CTA).
  
  
  RESULTS
  There was a smaller proportion of outliers for HKA, CFA and CTA at 10, 2 and 2 % respectively, in the pinless navigation group, compared to 32, 16 and 16 %, respectively, in the conventional group (p = 0.013, p = 0.032 and p = 0.032, respectively). The mean CFA was also more accurate at 90° in the pinless navigation group compared to 91° in the conventional group (p = 0.002). There was no difference in the duration of surgery between the two groups (n.s.).
  
  
  CONCLUSIONS
  Pinless navigation improves lower limb alignment and components placement without a significant increase in the duration of surgery. The authors recommend the use of pinless navigation to verify the coronal alignments of conventional cutting blocks in TKA before the bone cuts are made.
  
  
  METHODS
  I.
authors.affiliation: Department of Orthopaedic Surgery, Singapore General Hospital, Outram Road, Academia Building Level 4, Singapore, 119228, Singapore. yqjchen@gmail.com.
authors.forename: Jerry Yongqiang
authors.initials: JY
authors.lastname: Chen
authors.affiliation: Department of Orthopaedic Surgery, Singapore General Hospital, Outram Road, Academia Building Level 4, Singapore, 119228, Singapore.
authors.forename: Pak Lin
authors.initials: PL
authors.lastname: Chin
authors.affiliation: Department of Orthopaedic Surgery, Singapore General Hospital, Outram Road, Academia Building Level 4, Singapore, 119228, Singapore.
authors.forename: Zongxian
authors.initials: Z
authors.lastname: Li
authors.affiliation: Department of Orthopaedic Surgery, Singapore General Hospital, Outram Road, Academia Building Level 4, Singapore, 119228, Singapore.
authors.forename: Andy Khye Soon
authors.initials: AK
authors.lastname: Yew
authors.affiliation: Department of Orthopaedic Surgery, Singapore General Hospital, Outram Road, Academia Building Level 4, Singapore, 119228, Singapore.
authors.forename: Darren Keng Jin
authors.initials: DK
authors.lastname: Tay
authors.affiliation: Department of Orthopaedic Surgery, Singapore General Hospital, Outram Road, Academia Building Level 4, Singapore, 119228, Singapore.
authors.forename: Shi-Lu
authors.initials: SL
authors.lastname: Chia
authors.affiliation: Department of Orthopaedic Surgery, Singapore General Hospital, Outram Road, Academia Building Level 4, Singapore, 119228, Singapore.
authors.forename: Ngai Nung
authors.initials: NN
authors.lastname: Lo
authors.affiliation: Department of Orthopaedic Surgery, Singapore General Hospital, Outram Road, Academia Building Level 4, Singapore, 119228, Singapore.
authors.forename: Seng Jin
authors.initials: SJ
authors.lastname: Yeo
mesh_terms: D000368:Aged; D019645:Arthroplasty, Replacement, Knee / Q000379:methods*; D017760:Bone Malalignment / Q000517:prevention & control*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging / Q000601:surgery*; D035002:Lower Extremity / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011859:Radiography; D013238:Stereotaxic Techniques; D025321:Surgery, Computer-Assisted; D013977:Tibia / Q000000981:diagnostic imaging / Q000601:surgery
keywords: Components placement; Mechanical axis; Pinless navigation; Total knee arthroplasty