title: Does Residual Varus Alignment Cause Increasing Varus Laxity at a Minimum of Five Years After Total Knee Arthroplasty?
abstract: The purpose of this study is to investigate whether varus-valgus laxity of cruciate-retaining (CR) total knee arthroplasty (TKA) changes between 1 year and >5 years after surgery based on postoperative limb alignment.
  
  
  
  One hundred twenty-one varus osteoarthritic knees that underwent CR TKA were included. The minimum follow-up was 5 years. Weight-bearing full-leg radiographs were obtained postoperatively and the hip-knee-ankle (HKA) angle was measured. Knees were grouped in varus (HKA angle ≤ -3°, 47 knees) and neutral groups (-3° < HKA angle < 3°, 70 knees). The range of motion was measured and a Hospital for Special Surgery score was obtained at the last follow-up. Varus-valgus laxity at 15° of knee flexion was measured with stress radiographs after 1 year and at the last follow-up.
  
  
  
  No knees required revision surgery. The mean knee flexion angle (121.0° vs 117.1°) and Hospital for Special Surgery score (90.3 vs 90.4) at the last follow-up were not significantly different between the varus and neutral groups. In both groups, there was no significant change in varus or valgus laxity between 1 year and at the last follow-up.
  
  
  
  Postoperative residual varus limb alignment did not lead to increasing varus laxity after CR TKA in the mid-term.
authors.affiliation: Department of Orthopaedic Surgery, Japan Community Health Care Organization, Gunma Central Hospital, Maebashi, Gunma, Japan.
authors.forename: Kazuhisa
authors.initials: K
authors.lastname: Hatayama
authors.affiliation: Department of Orthopaedic Surgery, Japan Community Health Care Organization, Gunma Central Hospital, Maebashi, Gunma, Japan.
authors.forename: Masanori
authors.initials: M
authors.lastname: Terauchi
authors.affiliation: Department of Orthopaedic Surgery, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan.
authors.forename: Kenichi
authors.initials: K
authors.lastname: Saito
authors.affiliation: Department of Orthopaedic Sports Surgery, Asakura Sports Rehabilitation Clinic, Maebashi, Gunma, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Higuchi
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000843:Ankle Joint / Q000000981:diagnostic imaging; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007593:Joint Instability / Q000209:etiology* / Q000503:physiopathology; D007717:Knee / Q000601:surgery; D007719:Knee Joint / Q000000981:diagnostic imaging / Q000502:physiology* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D011184:Postoperative Period; D011859:Radiography; D016059:Range of Motion, Articular; D016474:Weight-Bearing
keywords: coronal laxity; cruciate retaining; instability; limb alignment; total knee arthroplasty