title: Novel joint cupping clinical maneuver for ultrasonographic detection of knee joint effusions.
abstract: BACKGROUND
  Knee effusions occur due to traumatic and atraumatic causes. Clinical diagnosis currently relies on several provocative techniques to demonstrate knee joint effusions. Portable bedside ultrasonography (US) is becoming an adjunct to diagnosis of effusions. We hypothesized that a US approach with a clinical joint cupping maneuver increases sensitivity in identifying effusions as compared to US alone.
  
  
  METHODS
  Using unembalmed cadaver knees, we injected fluid to create effusions up to 10 mL. Each effusion volume was measured in a lateral transverse location with respect to the patella. For each effusion we applied a joint cupping maneuver from an inferior approach, and re-measured the effusion.
  
  
  RESULTS
  With increased volume of saline infusion, the mean depth of effusion on ultrasound imaging increased as well. Using a 2-mm cutoff, we visualized an effusion without the joint cupping maneuver at 2.5 mL and with the joint cupping technique at 1 mL. Mean effusion diameter increased on average 0.26 cm for the joint cupping maneuver as compared to without the maneuver. The effusion depth was statistically different at 2.5 and 7.5 mL (P < .05).
  
  
  CONCLUSIONS
  Utilizing a joint cupping technique in combination with US is a valuable tool in assessing knee effusions, especially those of subclinical levels. Effusion measurements are complicated by uneven distribution of effusion fluid. A clinical joint cupping maneuver concentrates the fluid in one recess of the joint, increasing the likelihood of fluid detection using US.
authors.affiliation: Virginia Tech Carilion School of Medicine, Roanoke, VA 24014, USA. Electronic address: ouryasev@carilionclinic.org.
authors.forename: Oleg
authors.initials: O
authors.lastname: Uryasev
authors.forename: Oliver C
authors.initials: OC
authors.lastname: Joseph
authors.forename: John P
authors.initials: JP
authors.lastname: McNamara
authors.forename: Apostolos P
authors.initials: AP
authors.lastname: Dallas
mesh_terms: D002102:Cadaver; D005122:Exudates and Transudates / Q000000981:diagnostic imaging*; D006801:Humans; D007270:Injections, Intra-Articular; D007719:Knee Joint / Q000000981:diagnostic imaging*; D019095:Point-of-Care Systems; D014463:Ultrasonography