Thumb CMC Grind Test

Purpose[edit | edit source]

The purpose of the Thumb CMC Grind Test is to assess the integrity of the thumb CMC joint. Reproduction of the patient's pain and crepitus is a positive test for arthrosis and synovitis. Therapists must be aware of the crank test which both evaluates the joint quality and translational laxity, the distraction test where a pain response indicates joint inflammation and volar compression of the first metacarpal base which also indicates joint inflammation[1].

Technique[edit | edit source]

The grind test is performed by gripping the patient's metacarpal bone of the thumb and moving it in a circle and loading it with gentle axial forces. A patient with thumb joint arthritis generally complains of a sudden sharp pain at the CMC joint which can also be associated with Crepitus[2]. This indicates a positive test[3].

Evidence[edit | edit source]

Studies on the specificity and sensitivity of the Grind test were performed by Merrit et al using two examiners and Choa et al. The results are shown below;

Sensitivity and Specificity Analysis[3]
Author Sensitivity Specificity
Merritt et al 42% 80%
Meritt et al 53% 93%
Choa et al 30% 96.7%

References[edit | edit source]

  1. Colditz JC, Koekebakker N. (2010) A New Splint Design for the Thumb CMC Joint [White Paper] published by Nea International bv / Push Braces, Maastricht-Airport, the Netherlands,
  2. accessed online October 17th, 2017
  3. 3.0 3.1 Model, Z., Liu, A. Y., Kang, L., Wolfe, S. W., Burket, J. C., & Lee, S. K. (2016). Evaluation of Physical Examination Tests for Thumb Basal Joint Osteoarthritis. Hand (New York, N.Y.), 11(1), 108–112.