title: Cortisol concentrations in human skeletal muscle tissue after phonophoresis with 10% hydrocortisone gel.
abstract: BACKGROUND
  The delivery of hydrocortisone through phonophoresis is a widely prescribed technique for the treatment of various musculoskeletal inflammatory conditions. However, limited scientific evidence exists to support the efficacy of phonophoresis in delivering hydrocortisone to skeletal muscle tissue in humans.
  
  
  OBJECTIVE
  To determine hydrocortisone (cortisol) concentrations in human skeletal muscle tissue after a phonophoresis treatment using 10% hydrocortisone gel.
  
  
  METHODS
  Randomized design in which 12 subjects were randomly assigned to either an ultrasound (sham) treatment or a 10% hydrocortisone phonophoresis treatment.
  
  
  METHODS
  Laboratory.
  
  
  METHODS
  Twelve healthy subjects (8 women, 4 men: age = 22.3 +/- 2.64 years, height = 168.28 +/- 8.19 cm, mass = 69.58 +/- 9.05 kg) with no history of musculoskeletal disease, preexisting inflammatory conditions, or recent orthopaedic injuries.
  
  
  METHODS
  Ultrasound at 1.0 MHz, 1.0 W/cm (2), at a continuous setting for 7 minutes was applied to a standardized area of the vastus lateralis muscle in both groups. The contralateral limb served as the control (no treatment) for both the sham and the phonophoresis groups.
  
  
  METHODS
  Vastus lateralis muscle biopsies were taken from both legs immediately after treatment, and cortisol concentrations were analyzed using an enzyme-linked immunosorbent assay.
  
  
  RESULTS
  We observed no significant difference in muscle cortisol concentration between the contralateral control limb and the treatment limb in either the sham or the phonophoresis group ( P > .05). No significant difference was noted when the treatment limbs in the sham and phonophoresis groups were compared ( P > .05).
  
  
  CONCLUSIONS
  Our data suggest that a 10% hydrocortisone-based phonophoresis treatment did not increase cortisol concentrations in human skeletal muscle tissue.
authors.affiliation: The University of Toledo, Toledo, OH, USA. thomas.mcloughlin@utoledo.edu.
authors.forename: Amanda R
authors.initials: AR
authors.lastname: Kuntz
authors.forename: Christine M
authors.initials: CM
authors.lastname: Griffiths
authors.forename: James M
authors.initials: JM
authors.lastname: Rankin
authors.forename: Charles W
authors.initials: CW
authors.lastname: Armstrong
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: McLoughlin