title: Different pattern in gap balancing between the cruciate-retaining and posterior-stabilized total knee arthroplasty.
abstract: OBJECTIVE
  In order to permit soft tissue balance under more physiological conditions during total knee arthroplasties (TKAs), an offset-type tensor was developed to obtain soft tissue balancing throughout the range of motion with reduced patello-femoral (PF) and aligned tibiofemoral joints. The main purpose of the present study was to assess intra-operative soft tissue balance using a navigation system with the offset-type tensor in both cruciate-retaining (CR) and posterior-stabilized (PS) TKAs.
  
  
  METHODS
  One hundred and twenty TKAs--80 CR and 40 PS--were performed in patients with varus-type osteoarthritis using a computed tomography-free navigation system. The offset-type TKA tensor with a reduced and repaired PF joint and femoral component in place was used with the tibia first gap technique to balance soft tissues (joint component gap and ligament balance) at 0°, 10°, 30°, 60°, 90°, and 120° of flexion. The achievement in equalized rectangular gap at extension and flexion--joint component gap within ±3 mm between extension and flexion and ligament balance within ±3° at extension and flexion--was assessed retrospectively.
  
  
  RESULTS
  Both types of implants showed similar patterns of soft tissue balance throughout the range of motion, whereas PS TKA had larger values especially at 60° or 90° of flexion than did CR TKA. In the achievement of equalized rectangular gaps at extension and flexion, CR TKA was superior to PS TKA.
  
  
  CONCLUSIONS
  Using the tibia first gap technique with the tensor allows appropriate soft tissue balancing, especially in CR TKA.
  
  
  METHODS
  Therapeutic studies, Level II.
authors: Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, 7-5-1, Kusunoki-cho, Chuo-ku, Kobe, 650-0017, Japan, mastun@m4.dion.ne.jp.
authors: Tomoyuki
authors: T
authors: Matsumoto
authors: Seiji
authors: S
authors: Kubo
authors: Hirotsugu
authors: H
authors: Muratsu
authors: Takehiko
authors: T
authors: Matsushita
authors: Kazunari
authors: K
authors: Ishida
authors: Yohei
authors: Y
authors: Kawakami
authors: Shinya
authors: S
authors: Oka
authors: Tokio
authors: T
authors: Matsuzaki
authors: Yuichi
authors: Y
authors: Kuroda
authors: Kotaro
authors: K
authors: Nishida
authors: Toshihiro
authors: T
authors: Akisue
authors: Ryosuke
authors: R
authors: Kuroda
authors: Masahiro
authors: M
authors: Kurosaka
mesh_terms: D000368:Aged; D019645:Arthroplasty, Replacement, Knee / Q000295:instrumentation / Q000379:methods*; D001696:Biomechanical Phenomena; D005260:Female; D006801:Humans; D007720:Knee Prosthesis; D008297:Male; D020370:Osteoarthritis, Knee / Q000601:surgery*; D057071:Patellofemoral Joint / Q000502:physiology / Q000601:surgery; D016119:Posterior Cruciate Ligament / Q000601:surgery*; D016059:Range of Motion, Articular; D012189:Retrospective Studies; D025321:Surgery, Computer-Assisted / Q000295:instrumentation / Q000379:methods*; D016896:Treatment Outcome