title: Proximal interphalangeal joint stiffness: measurement and analysis.
abstract: OBJECTIVE
  The purpose of this study was to quantify the stiffness of the human finger proximal interphalangeal (PIP) joint and to study its relationship to different common clinical parameters.
  
  
  METHODS
  Eighty-nine normal adult subjects had their PIP joints of the index, middle, and ring fingers evaluated using a computer-controlled moment-angle plotter. This device was used to measure stiffness and energy absorbed at the PIP joint during passive flexion and extension.
  
  
  RESULTS
  The average overall stiffness was 0.05 N-cm/degree. There was a weak correlation between stiffness and energy absorbed and the size of the finger: they both increased with the size of the finger. The men's fingers were stiffer and absorbed more energy than the corresponding women's fingers. No significant associations were found between the time of day when the test took place, occupation, hobbies, or age with stiffness or absorbed energy. No significant differences were associated with hand dominance. The finger on the dominant hand had a larger circumference for both genders. Heavier individuals had more stiffness and absorbed more energy than lighter individuals.
  
  
  CONCLUSIONS
  The PIP joint stiffness was defined quantitatively and measured over a wide cross-section of a normal population. This may allow future studies to record the outcome of different treatments for finger joint stiffness objectively. The stiffness was greater in men and in larger fingers.
authors.affiliation: Department of Orthopaedic Surgery, University of California Los Angeles School of Medicine, Los Angeles, CA, USA.
authors.forename: Emil
authors.initials: E
authors.lastname: Dionysian
authors.forename: J Michael
authors.initials: JM
authors.lastname: Kabo
authors.forename: Frederick J
authors.initials: FJ
authors.lastname: Dorey
authors.forename: Roy A
authors.initials: RA
authors.lastname: Meals
mesh_terms: D000328:Adult; D000368:Aged; D001835:Body Weight; D016022:Case-Control Studies; D003198:Computer Simulation; D005260:Female; D005384:Finger Joint / Q000503:physiopathology*; D005385:Fingers / Q000033:anatomy & histology; D006801:Humans; D008297:Male; D008328:Man-Machine Systems; D008875:Middle Aged; D009068:Movement / Q000502:physiology; D016059:Range of Motion, Articular / Q000502:physiology*; D012737:Sex Factors