1. The CMC View: A Comparison of 3 Radiographic Views by Eaton-Glickel Classification and Correlation to Clinical Disease Severity
International Wrist Investigators Workshop 2015
September 2015
Presenter: Deana Mercer, MD
Christina Salas, PhD; Cory Carlston, MD; Norfleet Thompson, MD; Alfred Lopez, BS; Moheb Moneim, MD

2. Disclosures The authors have no disclosures
No relevant financial disclosures

3. Purpose
To determine the efficacy for use of the CMC view as a means for radiographic staging of the thumb carpometacarpal (CMC) joint
To investigate how the CMC view compares with two commonly used views of the thumb CMC joint when predicting clinical disease severity

4. Materials and methods
20 fresh-frozen, female cadaveric hands were used for this study (35-87 y/o; 10 L, 10 R)
Hands were x-rayed in 3 positions by trained radiology tech:
CMC view
PA view
Robert’s view
CMC view
PA view
Robert’s view

5. Materials and methods The CMC view (introduced at IWIW 2014)
Hand in lateral position, wrist in ulnar deviation
Radiolucent sponge placed under hand (allows view of CMC and STT joints)
Thumb placed on sponge crest, hand rests on downward slope

6. Materials and methods
60 images (20 P/A, 20 CMC, 20 Robert’s) were blinded, randomized to reviewers
3 fellowship trained hand surgeons, 2 hand fellows staged each radiograph using Eaton-Glickel classification
Gross dissection and inspection of trapezium, first metacarpal, and STT joint surfaces were completed
Disease severity graded using 0-4 numbering corresponding with E-G system

7. results Average Cohen’s Kappa (K) of interrater reliability across:
All views = 0.459
PA only = 0.461, CMC only = 0.411, Robert’s only = 0.508
Average K when comparing E-G classification to disease severity from gross dissection
PA only = 0.470, CMC only = 0.447, Robert’s only = 0.377 7

8. conclusions
Robert’s view allowed for greatest consistency in E-G staging among reviewers, but lowest correlation to disease severity
PA view allowed for greatest correlation to disease severity
CMC view moderately correlated to disease severity
CMC view performs as good as other commonly used techniques
It is easy to perform, with minimal potential for discomfort to the patient 8 8