title: Influence of index finger proximal interphalangeal joint arthrodesis on precision pinch kinematics.
abstract: OBJECTIVE
  To evaluate the impact of proximal interphalangeal (PIP) joint arthrodesis on the kinematics of precision pinch.
  
  
  METHODS
  Eleven healthy subjects performed index finger-thumb pinch motions under 4 conditions: unrestricted thumb and index finger (CONTROL) and fusion of the PIP joint of the index finger in flexion of 30° (PIP30), 40° (PIP40), and 50° (PIP50). Fusion was simulated with metallic splints. Kinematics of the thumb and index finger were recorded with a motion capture system.
  
  
  RESULTS
  Proximal interphalangeal joint fusion at 30°, 40°, and 50° restricted maximal pinch span between the thumb tip and index finger tip by 6%, 10%, and 14%, respectively. At the time of pulp contact, PIP fusion led to an increase in index metacarpophalangeal joint flexion angle for the PIP30 condition and an increase in variability of thumb tip location for the PIP50 condition. Furthermore, the dynamic coordination between joint angles throughout the movement was affected by PIP fusion.
  
  
  CONCLUSIONS
  This study reports impairment in the kinematics of precision pinch associated with index finger PIP joint fusion. A PIP joint fusion at 40° to 50° leads to a more natural precision pinch posture, but it restricts the aperture and reduces pinch precision.
authors: Department of Biomedical Engineering, Cleveland Clinic, Cleveland, OH, USA.
authors: Mathieu
authors: M
authors: Domalain
authors: Peter J
authors: PJ
authors: Evans
authors: William H
authors: WH
authors: Seitz
authors: Zong-Ming
authors: ZM
authors: Li
mesh_terms: D001174:Arthrodesis / Q000379:methods*; D001696:Biomechanical Phenomena; D005384:Finger Joint / Q000502:physiology* / Q000601:surgery*; D006801:Humans; D009048:Motor Skills / Q000502:physiology*; D016059:Range of Motion, Articular / Q000502:physiology*; D013933:Thumb / Q000502:physiology*; D055815:Young Adult