title: [Impact of muscle strength on knee joint stability in static loading].
abstract: OBJECTIVE
  To study the in vivo stability of normal and anterior cruciate ligament (ACL)-injured knee joint before and after epidural anesthesia under 134 N pre-loading and evaluate the influence of muscular tension on the knee stability.
  
  
  METHODS
  Eight volunteers with unilateral ACL rupture and normal contralateral knee were enrolled in this study. CT (3D) images and 2 orthogonal images of the knee were captured at 0°, 30°, 60°, and 90° under 134 N pre-loading. The orthogonal images were used to recreate the in vivo knee positions at each of the targeted flexion angles by 2D/3D registration to analyze the tibial translation data.
  
  
  RESULTS
  The anterior tibia translation of both the intact and ACL-injured knees after anesthesia was significantly different from that before anesthesia at all the angles (P<0.05). The anterior tibial translation of the intact knee after anesthesia increased by 1.7 mm at 0°, 2.7 mm at 30°, 2.6 mm at 60°, and 2.3 mm at 90°, as compare to the increase of ACL-injured knee by 4.2 mm, 2.6 mm, 1.2 mm, and 1.6 mm, respectively.
  
  
  CONCLUSIONS
  The muscular tension has evident influence on the knee stability in static loading.
authors.affiliation: Department of Orthopedics, Guangzhou General Hospital of Guangzhou Command, China. lipingyue09@126.com
authors.forename: Ping-yue
authors.initials: PY
authors.lastname: Li
authors.forename: Qing-shui
authors.initials: QS
authors.lastname: Yin
authors.forename: Hua-yang
authors.initials: HY
authors.lastname: Hang
authors.forename: Jian-yi
authors.initials: JY
authors.lastname: Li
authors.forename: Hong-yuan
authors.initials: HY
authors.lastname: Shen
authors.forename: Ze-jin
authors.initials: ZJ
authors.lastname: Wang
authors.forename: Qing
authors.initials: Q
authors.lastname: Wang
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D007593:Joint Instability; D007719:Knee Joint / Q000502:physiology*; D008297:Male; D053580:Muscle Strength; D055815:Young Adult