title: Navigation-based femorotibial rotation pattern correlated with flexion angle after total knee arthroplasty.
abstract: OBJECTIVE
  To investigate whether intraoperative kinematics obtained by navigation systems can be divided into several kinematic patterns and to assess the correlation between the intraoperative kinematics with maximum flexion angles before and after total knee arthroplasty (TKA).
  
  
  METHODS
  Fifty-four posterior-stabilised (PS) TKA implanted using an image-free navigation system were evaluated. At registration and after implantation, tibial internal rotation angles at maximum extension, 30°, 45°, 60°, 90°, and maximum flexion were collected. The rotational patterns were divided into four groups and were examined the correlation with maximum flexion before and after operation.
  
  
  RESULTS
  Tibial internal rotation from 90° of flexion to maximum flexion at registration was correlated with maximum flexion angles pre- and postoperatively. The four groups showed statistically different kinematic patterns. The group with tibial external rotation up to 90° of flexion, following tibial internal rotation at registration, achieved better flexion angles, compared to those of another groups (126.7° ± 12.0°, p < 0.05). The group with tibial external rotation showed the worst flexion angles (80.0° ± 40.4°, p < 0.05). Furthermore, the group with limited extension showed worse flexion angles (111.6° ± 8.9°, p < 0.05).
  
  
  CONCLUSIONS
  Navigation-based kinematic patterns found at registration predict postoperative maximum flexion angle in PS TKA. Navigation-based kinematics can be useful information during TKA surgery.
  
  
  METHODS
  Diagnostic studies, development of diagnostic criteria in a consecutive series of patients and a universally applied "gold" standard, Level II.
authors.affiliation: Department of Orthopaedic Surgery, Kobe Kaisei Hospital, 3-11-15, Shinohara-Kita, Nada, Kobe, 657-0068, Japan. wavedreamer17@yahoo.co.jp.
authors.forename: Kazunari
authors.initials: K
authors.lastname: Ishida
authors.affiliation: Department of Orthopaedic Surgery, Kobe Kaisei Hospital, 3-11-15, Shinohara-Kita, Nada, Kobe, 657-0068, Japan.
authors.forename: Nao
authors.initials: N
authors.lastname: Shibanuma
authors.affiliation: Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, 7-5-1, Kusunoki, Chuo, Kobe, 650-0017, Japan.
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Matsumoto
authors.affiliation: Department of Orthopaedic Surgery, Kobe Kaisei Hospital, 3-11-15, Shinohara-Kita, Nada, Kobe, 657-0068, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Sasaki
authors.affiliation: Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, 7-5-1, Kusunoki, Chuo, Kobe, 650-0017, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Takayama
authors.affiliation: Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, 7-5-1, Kusunoki, Chuo, Kobe, 650-0017, Japan.
authors.forename: Tokio
authors.initials: T
authors.lastname: Matsuzaki
authors.affiliation: Department of Orthopaedic Surgery, Chibune General Hosipital, 2-2-45, Tsukuda, Nishi-yodogawa, Osaka, 555-0001, Japan.
authors.forename: Katsumasa
authors.initials: K
authors.lastname: Tei
authors.affiliation: Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, 7-5-1, Kusunoki, Chuo, Kobe, 650-0017, Japan.
authors.forename: Ryosuke
authors.initials: R
authors.lastname: Kuroda
authors.affiliation: Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, 7-5-1, Kusunoki, Chuo, Kobe, 650-0017, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Kurosaka
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee; D001696:Biomechanical Phenomena; D005260:Female; D005269:Femur / Q000503:physiopathology* / Q000601:surgery; D006801:Humans; D007719:Knee Joint / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D011184:Postoperative Period; D057234:Preoperative Period; D016059:Range of Motion, Articular; D012399:Rotation; D013238:Stereotaxic Techniques; D025321:Surgery, Computer-Assisted; D013977:Tibia / Q000503:physiopathology* / Q000601:surgery
keywords: Flexion contracture; Kinematics; Maximum flexion angle; Navigation; Total knee arthroplasty