title: In vivo three-dimensional elbow biomechanics during forearm rotation.
abstract: BACKGROUND
  It is unclear how elbow kinematics changes during forearm rotation. This study investigated in vivo 3-dimensional elbow kinematics during forearm rotation.
  
  
  METHODS
  We studied 12 normal elbows using in vivo 3-dimensional computed tomography data in maximum forearm supination, neutral, and maximum pronation with the elbows in extension. We measured the motion of the radius and ulna relative to the humerus using a markerless bone registration technique and the contact area of the radiocapitellar joint, proximal radioulnar joint, and ulnohumeral joint using a proximity mapping method.
  
  
  RESULTS
  When the forearm rotated from the supinated position to the pronated position, the radius showed significant varus rotation, internal rotation, and extension relative to the humerus. The center of the radial head significantly translated anteriorly, proximally, and laterally. The ulna significantly rotated in valgus, and the deepest point on the sagittal ridge of the trochlear notch translated medially with forearm pronation. The contact area of the radiocapitellar joint was largest in pronation. The contact area of the proximal radioulnar joint was largest in supination. The contact area of the ulnohumeral joint showed no significant change during forearm rotation.
  
  
  CONCLUSIONS
  In pronation, because of the proximal migration of the radial head, the radiocapitellar joint was most congruent compared with other positions. The proximal radioulnar joint was most congruent in supination. The ulnohumeral joint congruency was not affected by forearm rotation. This study provides useful information for understanding 3-dimensional elbow motion and joint osseous stability related to forearm rotation.
authors.affiliation: Department of Orthopaedic Surgery, Osaka University Graduate School of Medicine, Osaka, Japan.
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Omori
authors.affiliation: Department of Orthopaedic Surgery, Osaka University Graduate School of Medicine, Osaka, Japan.
authors.forename: Junichi
authors.initials: J
authors.lastname: Miyake
authors.affiliation: Department of Orthopaedic Surgery, Osaka University Graduate School of Medicine, Osaka, Japan.
authors.forename: Kunihiro
authors.initials: K
authors.lastname: Oka
authors.affiliation: Department of Orthopaedic Surgery, Osaka University Graduate School of Medicine, Osaka, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Tanaka
authors.affiliation: Department of Orthopaedic Surgery, Osaka University Graduate School of Medicine, Osaka, Japan.
authors.forename: Hideki
authors.initials: H
authors.lastname: Yoshikawa
authors.affiliation: Department of Orthopaedic Surgery, Osaka University Graduate School of Medicine, Osaka, Japan. Electronic address: tmurase-osk@umin.ac.jp.
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Murase
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena; D004551:Elbow Joint / Q000000981:diagnostic imaging / Q000502:physiology*; D005260:Female; D005542:Forearm / Q000000981:diagnostic imaging / Q000502:physiology*; D006801:Humans; D006811:Humerus / Q000000981:diagnostic imaging / Q000502:physiology*; D021621:Imaging, Three-Dimensional; D008297:Male; D008875:Middle Aged; D011403:Pronation; D011884:Radius / Q000000981:diagnostic imaging / Q000502:physiology*; D012399:Rotation; D013484:Supination; D014057:Tomography, X-Ray Computed; D014457:Ulna / Q000000981:diagnostic imaging / Q000502:physiology*; D055815:Young Adult
keywords: 3-Dimensional biomechanics; elbow joint; forearm rotation; in vivo