title: Kinematic TKA using navigation: Surgical technique and initial results.
abstract: BACKGROUND
  Kinematic alignment for total knee arthroplasty (TKA) may be one way of improving outcomes. Previous studies have either used patient-specific instrumentation, which adds cost, or standard instrumentation, which provides no intraoperative feedback on resection alignment.
  
  
  OBJECTIVE
  To determine if computer navigation could reproduce native patient anatomy and simplify ligament balance during TKA whilst giving satisfactory improvements in functional scores at early follow-up.
  
  
  METHODS
  Computer navigation was used for kinematic distal femoral and proximal tibial cuts in 100 consecutive and unselected TKAs. Resections were modified only if measured angles fell outside a pre-defined safe range of combined coronal orientation within±3 degrees of neutral and/or independent femoral or tibial cuts within±5 degrees. Pre- and postoperative measurements of the hip-knee-ankle (HKA) angle, the lateral distal femoral angle (LDFA) and the medial proximal tibial angle (MPTA) were taken using long-leg standing radiographs. Clinical evaluation was with the WOMAC and KOOS scales.
  
  
  RESULTS
  Mean follow-up was 2.4 years (range 1.0-3.7, SD 0.8). The mean pre-op LDFA was 2.1 degrees valgus (9.2 valgus to 3.7 varus, SD 2.5) and 1.8 degrees valgus post-op (5.7 valgus to 4.2 varus, SD 2.0) (P=0.41). The mean pre-op MPTA was 3.0 degrees varus (10.6 valgus to 10.2 varus, SD 3.2) and 2.4 degrees varus post-op (4.0 valgus to 6.8 varus, SD 2.2) (P=0.03). The mean WOMAC score improved from 49.4 (29-85, SD 12.8) to 24.7 (0-73, SD 16.5) (P<0.001) and the mean KOOS score from 37.1 (7.2-77.2, SD 13.0) to 65.1 (26.8-100, SD 16) (P<0.001). Five knees (5%) required additional ligament release, four with valgus OA and one with varus OA. Two knees (2%) required lateral retinacular release for patellar tracking.
  
  
  CONCLUSIONS
  Computer navigation for kinematic TKA provides the operating surgeon with full control and feedback at each step, whilst also allowing partial correction of more extreme anatomy that might be unsuitable for recreation during TKA. This technique helps to preserve ligament isometry and produces satisfactory improvements in functional scores.
  
  
  METHODS
  IV (retrospective case series review).
authors.affiliation: Université de Montréal, Hôpital Maisonneuve-Rosemont, Department of Surgery, 5415 boulevard de l'Assomption, Montréal, QC H1T 2M4, Canada.
authors.forename: J R B
authors.initials: JR
authors.lastname: Hutt
authors.affiliation: Université de Montréal, Hôpital Maisonneuve-Rosemont, Department of Surgery, 5415 boulevard de l'Assomption, Montréal, QC H1T 2M4, Canada.
authors.forename: M-A
authors.initials: MA
authors.lastname: LeBlanc
authors.affiliation: Université de Montréal, Hôpital Maisonneuve-Rosemont, Department of Surgery, 5415 boulevard de l'Assomption, Montréal, QC H1T 2M4, Canada.
authors.forename: V
authors.initials: V
authors.lastname: Massé
authors.affiliation: Université de Montréal, Hôpital Maisonneuve-Rosemont, Department of Surgery, 5415 boulevard de l'Assomption, Montréal, QC H1T 2M4, Canada.
authors.forename: M
authors.initials: M
authors.lastname: Lavigne
authors.affiliation: Université de Montréal, Hôpital Maisonneuve-Rosemont, Department of Surgery, 5415 boulevard de l'Assomption, Montréal, QC H1T 2M4, Canada. Electronic address: pa.vendittoli@me.com.
authors.forename: P-A
authors.initials: PA
authors.lastname: Vendittoli
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee / Q000379:methods*; D001696:Biomechanical Phenomena; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007719:Knee Joint / Q000601:surgery*; D008023:Ligaments, Articular / Q000601:surgery; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D025321:Surgery, Computer-Assisted
keywords: Kinematic; Knee Arthroplasty; Navigation; Outcomes; TKA; Technique