title: In vivo length change patterns of the medial and lateral collateral ligaments along the flexion path of the knee.
abstract: OBJECTIVE
  The knowledge of the function of the collateral ligaments-i.e., superficial medial collateral ligament (sMCL), deep medial collateral ligament (dMCL) and lateral collateral ligament (LCL)-in the entire range of knee flexion is important for soft tissue balance during total knee arthroplasty (TKA). The objective of this study was to investigate the length changes of different portions (anterior, middle and posterior) of the sMCL, dMCL and LCL during in vivo weightbearing flexion from full extension to maximal knee flexion.
  
  
  METHODS
  Using a dual fluoroscopic imaging system, eight healthy knees were imaged while performing a lunge from full extension to maximal flexion. The length changes of each portion of the collateral ligaments were measured along the flexion path of the knee.
  
  
  RESULTS
  All anterior portions of the collateral ligaments were shown to have increasing length with flexion except that of the sMCL, which showed a reduction in length at high flexion. The middle portions showed minimal change in lengths except that of the sMCL, which showed a consistent reduction in length with flexion. All posterior portions showed reduction in lengths with flexion.
  
  
  CONCLUSIONS
  These data indicated that every portion of the ligaments may play important roles in knee stability at different knee flexion range. The soft tissue releasing during TKA may need to consider the function of the ligament portions along the entire flexion path including maximum flexion.
  
  
  METHODS
  III.
authors.affiliation: Bioengineering Laboratory, Department of Orthopaedic Surgery, Massachusetts General Hospital/Harvard Medical School, 55 Fruit Street, GRJ 1215, Boston, MA, 02114, USA.
authors.forename: Ali
authors.initials: A
authors.lastname: Hosseini
authors.affiliation: Bioengineering Laboratory, Department of Orthopaedic Surgery, Massachusetts General Hospital/Harvard Medical School, 55 Fruit Street, GRJ 1215, Boston, MA, 02114, USA.|Department of Orthopaedic Surgery, Chinese PLA General Hospital, 28 Fuxing Road, Beijing, 100853, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Qi
authors.affiliation: Bioengineering Laboratory, Department of Orthopaedic Surgery, Massachusetts General Hospital/Harvard Medical School, 55 Fruit Street, GRJ 1215, Boston, MA, 02114, USA.
authors.forename: Tsung-Yuan
authors.initials: TY
authors.lastname: Tsai
authors.affiliation: Department of Orthopaedic Surgery, Chinese PLA General Hospital, 28 Fuxing Road, Beijing, 100853, China.
authors.forename: Yujie
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Bioengineering Laboratory, Department of Orthopaedic Surgery, Massachusetts General Hospital/Harvard Medical School, 55 Fruit Street, GRJ 1215, Boston, MA, 02114, USA.
authors.forename: Harry
authors.initials: H
authors.lastname: Rubash
authors.affiliation: Bioengineering Laboratory, Department of Orthopaedic Surgery, Massachusetts General Hospital/Harvard Medical School, 55 Fruit Street, GRJ 1215, Boston, MA, 02114, USA. gli1@partners.org.
authors.forename: Guoan
authors.initials: G
authors.lastname: Li
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D017885:Collateral Ligaments / Q000000981:diagnostic imaging* / Q000502:physiology; D005260:Female; D005471:Fluoroscopy / Q000379:methods*; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging* / Q000502:physiology; D017844:Lateral Ligament, Ankle / Q000000981:diagnostic imaging* / Q000502:physiology; D008297:Male; D016059:Range of Motion, Articular; D016474:Weight-Bearing
keywords: In vivo length change pattern; Lateral collateral ligament; Lunge; Medial collateral ligament