title: Intra-articular pressure measurement in the radioulnocarpal joint using a novel sensor: in vitro and in vivo results.
abstract: OBJECTIVE
  To determine the amount and distribution of forces transmitted across the human radioulnocarpal joint under physiologic conditions in vivo. We performed an in vitro validation of a specifically developed capacitive pressure-sensor device and an in vivo measurement of force transmission and pressure distribution at the radioulnocarpal joint in a healthy volunteer.
  
  
  METHODS
  A new capacitive pressure-sensor device was adapted for intra-articular pressure measurement in the human radioulnocarpal joint. The technical characteristics of the device were determined and the sensor was validated in fresh-frozen cadaver tests. Force transmission across the radioulnocarpal joint then was measured in healthy volunteers under local anesthesia.
  
  
  RESULTS
  The sensor delivered reproducible measurements of forces across the radioulnocarpal joint and their distribution in the cadaver experiment. In vivo, 2 centers of force transmission were identified. None of these centers correlated with previous findings in the literature. More force is transmitted across the ulnar side of the radioulnocarpal joint than previously thought. The results are consistent with clinical findings.
  
  
  CONCLUSIONS
  The novel sensor device is suitable for intra-articular pressure measurement in the human radioulnocarpal joint in vitro and in vivo.
authors.affiliation: Surgical Department, Kantonsspital Lucerne, Lucerne, Switzerland. daniel.rikli@ksl.ch
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Rikli
authors.forename: Philipp
authors.initials: P
authors.lastname: Honigmann
authors.forename: Reto
authors.initials: R
authors.lastname: Babst
authors.forename: Alessandra
authors.initials: A
authors.lastname: Cristalli
authors.forename: Michael M
authors.initials: MM
authors.lastname: Morlock
authors.forename: Thomas
authors.initials: T
authors.lastname: Mittlmeier
mesh_terms: D001696:Biomechanical Phenomena; D006801:Humans; D011312:Pressure; D013314:Stress, Mechanical; D014160:Transducers, Pressure; D014955:Wrist Joint / Q000502:physiology*