title: Clinical alignment variations in total knee arthroplasty with different navigation methods.
abstract: BACKGROUND
  We compared the resulting alignment in 90° of flexion and in full extension after total knee arthroplasty (TKA) with two navigation systems using different techniques: a measured resection (MR) system and a gap - balancing (GB) system.
  
  
  METHODS
  Varus and valgus alignment in extension and flexion was compared in 100 consecutive patients who had TKA with an MR distal-femoral-cut-first technique at one institution and 100 consecutive patients in whom a GB tibial-cut-first technique was used at another institution. Alignment deviation of three degrees or more from neutral was considered an outlier.
  
  
  RESULTS
  No significant difference between the groups in coronal alignment in extension or flexion was found, but there were three times the number of outliers for clinical alignment in flexion for the MR group compared to the GB group.
  
  
  CONCLUSIONS
  The use of the GB tibial-cut-first computer-assisted TKA navigation may provide a more consistent clinical alignment in flexion than systems using an MR technique.
  
  
  METHODS
  Therapeutic study. Level 2.
authors.affiliation: University of Tennessee - Campbell Clinic Department of Orthopaedics & Biomedical Engineering, 1211 Union Ave, Suite 510, Memphis, TN 38104, USA.
authors.forename: Byron F
authors.initials: BF
authors.lastname: Stephens
authors.affiliation: Department of Orthopaedic Surgery, Bay Pines Veterans Administration Health Care System, 10000 Bay Pines Boulevard North, Bay Pines, FL 33744, USA.
authors.forename: Sam
authors.initials: S
authors.lastname: Hakki
authors.affiliation: Southern Illinois University, Division of Orthopaedic Surgery, 520N 4th St # 202 Springfield, IL 62702, USA.
authors.forename: Khaled J
authors.initials: KJ
authors.lastname: Saleh
authors.affiliation: Campbell Clinic Department of Orthopaedic Surgery & Biomedical Engineering, University of Tennessee, 956 Court Ave, Suite E226, Memphis, TN 38163, USA. Electronic address: wmihalko@campbellclinic.com.
authors.forename: William M
authors.initials: WM
authors.lastname: Mihalko
mesh_terms: D000328:Adult; D019645:Arthroplasty, Replacement, Knee / Q000295:instrumentation*; D004867:Equipment Design; D006801:Humans; D016916:Joint Deformities, Acquired / Q000209:etiology / Q000473:pathology* / Q000601:surgery*; D016059:Range of Motion, Articular; D012189:Retrospective Studies; D025321:Surgery, Computer-Assisted / Q000295:instrumentation*; D016896:Treatment Outcome
keywords: Alignment; Arthroplasty; Computer navigation; Knee