title: Three-dimensional in vivo kinematics during elbow flexion in patients with lateral humeral condyle nonunion by an image-matching technique.
abstract: BACKGROUND
  An established nonunion of the lateral humeral condyle often reveals elbow instability and accompanying pain. The purpose of this study was to obtain 3-dimensional and quantitative information about the pathologic kinematics of the ulnohumeral joint with nonunion of the lateral humeral condyle by an in vivo and 3-dimensional motion analysis.
  
  
  METHODS
  Magnetic resonance or computed tomography images of the elbows of 14 patients were acquired in 3 positions between full extension and full flexion. We evaluated ulnohumeral motion and calculated the change in the length of the medial collateral ligament during elbow flexion.
  
  
  RESULTS
  Ulnohumeral motion was associated with an excessive lateral shift of ulnar movement. In addition, the distal part of the ulna was rotated in the varus direction, leading to a decrease in the carrying angle. The ulna tended to exhibit internal rotation from full extension to 90° of flexion of the elbow. With further flexion, the ulna rotated externally and returned to its neutral position. Furthermore, the length of the medial collateral ligament increased with an increase in the elbow flexion angle.
  
  
  CONCLUSIONS
  Patients with lateral humeral condyle nonunion showed excessive lateral shift of the ulna and ulnar axial rotation. Also, the lateral shift caused an osseous protrusion of the medial trochlea, leading to elongation of the medial collateral ligament.
authors: Department of Orthopaedic Surgery, Osaka University, Graduate School of Medicine, Osaka, Japan. Electronic address: goto-akira@umin.ac.jp.
authors: Akira
authors: A
authors: Goto
authors: Department of Orthopaedic Surgery, Osaka University, Graduate School of Medicine, Osaka, Japan.
authors: Tsuyoshi
authors: T
authors: Murase
authors: Department of Physical Therapy, Osaka Yukioka College of Health Science, Osaka, Japan.
authors: Hisao
authors: H
authors: Moritomo
authors: Department of Orthopaedic Surgery, Osaka University, Graduate School of Medicine, Osaka, Japan.
authors: Kunihiro
authors: K
authors: Oka
authors: Department of Orthopaedic Biomaterial Science, Osaka University, Graduate School of Medicine, Osaka, Japan.
authors: Kazuomi
authors: K
authors: Sugamoto
authors: Department of Orthopaedic Surgery, Osaka University, Graduate School of Medicine, Osaka, Japan.
authors: Hideki
authors: H
authors: Yoshikawa
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D002102:Cadaver; D017885:Collateral Ligaments / Q000473:pathology / Q000503:physiopathology; D004550:Elbow / Q000000981:diagnostic imaging / Q000503:physiopathology*; D005260:Female; D057918:Fiducial Markers; D005599:Fractures, Ununited / Q000175:diagnosis / Q000503:physiopathology*; D006801:Humans; D006811:Humerus / Q000000981:diagnostic imaging / Q000503:physiopathology*; D021621:Imaging, Three-Dimensional; D007593:Joint Instability / Q000175:diagnosis / Q000503:physiopathology; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D008953:Models, Anatomic; D016059:Range of Motion, Articular; D012399:Rotation; D014057:Tomography, X-Ray Computed; D000092464:Elbow Injuries
keywords: Elbow; in vivo; medial collateral ligament; three-dimensional kinematics