title: Validation of a photography-based goniometry method for measuring joint range of motion.
abstract: BACKGROUND
  A critical component of evaluating the outcomes after surgery to restore lost elbow motion is the range of motion (ROM) of the elbow. This study examined if digital photography-based goniometry is as accurate and reliable as clinical goniometry for measuring elbow ROM.
  
  
  METHODS
  Instrument validity and reliability for photography-based goniometry were evaluated for a consecutive series of 50 elbow contractures by 4 observers with different levels of elbow experience. Goniometric ROM measurements were taken with the elbows in full extension and full flexion directly in the clinic (once) and from digital photographs (twice in a blinded random manner).
  
  
  RESULTS
  Instrument validity for photography-based goniometry was extremely high (intraclass correlation coefficient: extension = 0.98, flexion = 0.96). For extension and flexion measurements by the expert surgeon, systematic error was negligible (0° and 1°, respectively). Limits of agreement were 7° (95% confidence interval [CI], 5° to 9°) and -7° (95% CI, -5° to -9°) for extension and 8° (95% CI, 6° to 10°) and -7° (95% CI, -5° to -9°) for flexion. Interobserver reliability for photography-based goniometry was better than that for clinical goniometry. The least experienced observer's photographic goniometry measurements were closer to the reference measurements than the clinical goniometry measurements.
  
  
  CONCLUSIONS
  Photography-based goniometry is accurate and reliable for measuring elbow ROM. The photography-based method relied less on observer expertise than clinical goniometry. This validates an objective measure of patient outcome without requiring doctor-patient contact at a tertiary care center, where most contracture surgeries are done.
authors: Mayo Clinic, Department of Orthopedic Surgery, Rochester, MN, USA.
authors: Davide
authors: D
authors: Blonna
authors: Peter C
authors: PC
authors: Zarkadas
authors: James S
authors: JS
authors: Fitzsimmons
authors: Shawn W
authors: SW
authors: O'Driscoll
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D053587:Arthrometry, Articular / Q000379:methods*; D003286:Contracture / Q000175:diagnosis* / Q000503:physiopathology; D018592:Cross-Over Studies; D004551:Elbow Joint / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010781:Photography; D016059:Range of Motion, Articular; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D055815:Young Adult