title: Fluoroscopy-assisted stress testing of the thumb metacarpophalangeal joint to assess the ulnar collateral ligament.
abstract: BACKGROUND
  Diagnostic stress testing of ulnar collateral ligament (UCL) injuries of the thumb metacarpophalangeal (MCP) joint is pivotal to determining treatment. Comparison to the uninjured extremity and fluoroscopy-assisted examination are readily available modalities in the assessment of these patients, with 5-10° differences impacting treatment. Comparative examination, however, assumes that both extremities are normally equal, which has never been verified experimentally. Comparison of clinical and fluoroscopic examination has also never been scrutinized.
  
  
  METHODS
  One hundred asymptomatic participants underwent both fluoroscopic and traditional stress examinations to determine maximum passive radial deviation at neutral MCP flexion.
  
  
  RESULTS
  Absolute clinical vs. fluoroscopic differences demonstrated a significant difference of 5.6° (SD 5.1°). Absolute variability between left-to-right measurements was 4.5° (SD 4.1°) and increased significantly as baseline stress deviation increased (R = 0.43; p < 0.001). Left-to-right difference exhibited no correlation to age, gender, or BMI.
  
  
  CONCLUSIONS
  The current investigation demonstrates right-left differences and differences between clinical and fluoroscopic testing of which practitioners should be aware when making treatment decisions for UCL injury of the thumb MCP joint.
authors.affiliation: Department of Orthopaedic Surgery, Maimonides Medical Center, 927 49th St., Brooklyn, NY 11219 USA.
authors.forename: Ashish
authors.initials: A
authors.lastname: Patel
authors.affiliation: Department of Orthopaedic Surgery, Maimonides Medical Center, 927 49th St., Brooklyn, NY 11219 USA.
authors.forename: Archit
authors.initials: A
authors.lastname: Patel
authors.affiliation: Department of Orthopaedic Surgery, Maimonides Medical Center, 927 49th St., Brooklyn, NY 11219 USA.
authors.forename: David
authors.initials: D
authors.lastname: Edelstein
authors.affiliation: Department of Orthopaedic Surgery, Maimonides Medical Center, 927 49th St., Brooklyn, NY 11219 USA.
authors.forename: Jack
authors.initials: J
authors.lastname: Choueka
keywords: Gamekeeper’s thumb; Goniometry; Joint laxity; Skier’s thumb; Stress testing; Thumb metacarpophalangeal joint; Thumb ulnar collateral ligament