title: No impact of under-correction and joint line obliquity on clinical outcomes of total knee arthroplasty for the varus knee.
abstract: OBJECTIVE
  It has been hypothesized that under-correction of a preoperative varus deformity may be more natural and improve outcomes after total knee arthroplasty (TKA). This study's purpose was to assess the impact of hip-knee-ankle (HKA) alignment and joint line obliquity on TKA outcomes for the varus knee.
  
  
  METHODS
  All patients with a preoperative varus deformity received both preoperative and postoperative standing, full-length radiographs from which two independent observers performed radiographic measurements including the HKA axis and mechanical medial proximal tibial angle (mMPTA). Patients were categorized based on their HKA into neutral (0° ± 3°), mild varus (-6° to -3°), severe varus (≤ -6°), and valgus (>3°) cohorts, and separately categorized based on their mMPTA into neutral (90° ± 2°), mild varus (86°-88°), severe varus (<86°), and valgus (>92°) cohorts.
  
  
  RESULTS
  Two hundred and fifty-six patients (mean age 63.8 ± 9.0 years, BMI 33.0 ± 6.2 kg/m2, follow-up 1.3 ± 0.6 years) were included. There was no difference in the postoperative SF-12 physical component, mental component, Oxford knee, Forgotten Joint Score, or incremental improvement in scores based on the postoperative alignment category for either the HKA or mMPTA. There was no correlation between the magnitude of change in HKA (r = 0.03-0.1) and mMPTA (r = 0.02-0.1) from preoperatively to postoperatively with clinical outcomes.
  
  
  CONCLUSIONS
  In patients undergoing TKA for a preoperative varus deformity, a specific postoperative HKA or mMPTA alignment category was not associated with improved outcomes. Therefore, categorization of optimal postoperative alignment after TKA may not be possible as static, coronal alignment is just one of many variables that can impact clinical outcomes. Future investigations focusing on the combination of static images with dynamic examinations and ligamentous balancing may shed further insight into the controversy and importance of coronal alignment following TKA.
  
  
  METHODS
  III.
authors.affiliation: Department of Orthopedic Surgery, Washington University School of Medicine/Barnes-Jewish Hospital, 660 S. Euclid Avenue, Campus Box 8233, St. Louis, MO, 63110, USA.
authors.forename: Richard D
authors.initials: RD
authors.lastname: Rames
authors.affiliation: Department of Orthopedic Surgery, Washington University School of Medicine/Barnes-Jewish Hospital, 660 S. Euclid Avenue, Campus Box 8233, St. Louis, MO, 63110, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Mathison
authors.affiliation: Department of Orthopedic Surgery, Washington University School of Medicine/Barnes-Jewish Hospital, 660 S. Euclid Avenue, Campus Box 8233, St. Louis, MO, 63110, USA.
authors.forename: Zachary
authors.initials: Z
authors.lastname: Meyer
authors.affiliation: Department of Orthopedic Surgery, Washington University School of Medicine/Barnes-Jewish Hospital, 660 S. Euclid Avenue, Campus Box 8233, St. Louis, MO, 63110, USA.
authors.forename: Robert L
authors.initials: RL
authors.lastname: Barrack
authors.affiliation: Department of Orthopedic Surgery, Rush University Medical Center, 1611 West Harrison Street, Suite 300, Chicago, IL, 60612, USA. denis.nam@rushortho.com.
authors.forename: Denis
authors.initials: D
authors.lastname: Nam
mesh_terms: D000368:Aged; D019645:Arthroplasty, Replacement, Knee / Q000379:methods*; D005260:Female; D056305:Genu Varum / Q000503:physiopathology* / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D011184:Postoperative Period; D011187:Posture; D011859:Radiography; D012189:Retrospective Studies
keywords: Joint line obliquity; Outcomes; Total knee arthroplasty; Under-correction; Varus