Thumb Disability Examination (TDX) as a New Reliable Tool for Basal Joint Arthritis

Background  The general assessment of basal joint arthritis (BJA) is limited using the Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire. This has been shown to be insensitive to pain and disability levels, leading to the development and validation of the thumb disability examination (TDX) as a specific tool for BJA in 2014. Objective  The goal of this study was to evaluate the reliability, sensitivity, and specificity of the TDX score for BJA. Methods  A multicenter BJA database was established in 2007 to collect prospective data. We evaluated the correlation between the TDX score, visual analog pain scale with activity (A-VAS), Eaton-Littler score, and grip strength using a Pearson test. Additionally, we evaluated the pre- and postintervention scores to assess their predictive values. Results  A total of 109 thumbs of 74 patients with TDX scores were evaluated. Females were more commonly affected (75.2%), and the mean age was 65.39 years (standard deviation: 10.04). The majority of participants were white (90.8%). A high correlation between TDX and A-VAS score (Pearson's correlation = 0.520; p  < 0.001) and between grip strength (Pearson's correlation = -0.336; p  < 0.005) and Eaton-Littler score (Pearson's correlation = 0.353' p  < 0.01) was identified. Additionally, when comparing pre- and post-intervention for all treatment groups and for operative intervention, significant differences in TDX scores were observed (both p ≤ 0.01). No significant differences could be identified for DASH score or A-VAS when assessing these same groups. Conclusion  The TDX score correlates to high Pearson's correlation values and p -values, especially in grip strength, Eaton-Littler score, A-VAS score, and pre-/postintervention for all treatment groups combined and when specifically assessing the surgical intervention group. As a result, it can be concluded that the TDX score is a specific tool for the assessment of BJA. Level of Evidence  This is a Level II, prospective comparative study.