title: Coronal tibiofemoral subluxation in knee osteoarthritis.
abstract: OBJECTIVE
  To analyze knees in varying stages of osteoarthritis (OA) for the presence of coronal tibiofemoral (CTF) subluxation and to determine if CTF subluxation severity is related to knee OA worsening.
  
  
  METHODS
  We retrospectively evaluated CTF subluxation and limb alignment in 113 patients with different stages of knee OA who were being considered for an arthroplasty procedure. Knee OA was classified as "mild" or "severe" according to Kellgren-Lawrence scale. CTF subluxation was measured in the study groups and in 40 knees of healthy controls using software developed specifically on the basis of Iterative Closest Point mathematical algorithm.
  
  
  RESULTS
  Mean CTF subluxation in "mild OA" and "severe OA" groups was 3.5% (±2) and 3.5 % (±5) of the tibial plateau, respectively. For both the mild and severe OA groups, CTF subluxation was significantly increased compared to the 1.4% (±1) CTF subluxation in the control group, (p < 0.0001) and (p = 0.012), respectively. However, there was no significant difference in CTF subluxation between the mild OA and severe OA groups (p = 0.75). Limb varus malalignment in mild OA and severe OA groups was 3.6° (±2.2) and 5.3° (±2.6), respectively. Both significantly increased comparing to the 1° (±0.7) control group alignment (p < 0.0001). Varus malalignment in the severe OA group was significantly increased comparing to the mild OA group (p = 0.0003).
  
  
  CONCLUSIONS
  CTF subluxation is a radiographic finding related to knee OA which occurs mainly in the early stages of the osteoarthritic process and stagnates as OA progresses.
authors: Computer Assisted Surgery Center, Department of Orthopedic Surgery, Hospital for Special Surgery, Weill Medical College of Cornell University, 535 E. 70th Street, New York, NY, 10021, USA. saker.khamaisy@gmail.com.
authors: Saker
authors: S
authors: Khamaisy
authors: Computer Assisted Surgery Center, Department of Orthopedic Surgery, Hospital for Special Surgery, Weill Medical College of Cornell University, 535 E. 70th Street, New York, NY, 10021, USA.
authors: Hendrik A
authors: HA
authors: Zuiderbaan
authors: Computer Assisted Surgery Center, Department of Orthopedic Surgery, Hospital for Special Surgery, Weill Medical College of Cornell University, 535 E. 70th Street, New York, NY, 10021, USA.
authors: Ran
authors: R
authors: Thein
authors: Computer Assisted Surgery Center, Department of Orthopedic Surgery, Hospital for Special Surgery, Weill Medical College of Cornell University, 535 E. 70th Street, New York, NY, 10021, USA.
authors: Brian P
authors: BP
authors: Gladnick
authors: Computer Assisted Surgery Center, Department of Orthopedic Surgery, Hospital for Special Surgery, Weill Medical College of Cornell University, 535 E. 70th Street, New York, NY, 10021, USA.
authors: Andrew D
authors: AD
authors: Pearle
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D031221:Knee Dislocation / Q000000981:diagnostic imaging* / Q000209:etiology*; D007719:Knee Joint / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D020370:Osteoarthritis, Knee / Q000150:complications* / Q000000981:diagnostic imaging*; D011859:Radiography; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
keywords: Coronal tibiofemoral subluxation; Knee osteoarthritis; Limb alignment