Assessing the severity of carpal tunnel syndrome during physical examination by measuring two-point discrimination: Post-hoc analysis of prospectively collected data

•Carpal tunnel syndrome is a common and detrimental complication after distal radius fracture, that might need additional operative treatment.•Two-point discrimination measurement is a reliable, easily applicable tool to assess the sensory function of the hand.•Determining the severity of carpal tunnel syndrome during physical examination could contribute to more effective patient care.•Two-point discrimination values show correlation with the results of electrophysiological examination, but they are not interchangeable.•Two-point discrimination values over 10 mms should be considered as an indicative for severe carpal tunnel syndrome. Carpal tunnel syndrome (CTS) commonly presents after distal radius fractures. Assessing its degree of severity is essential to therapeutic decision-making - i.e. operative vs. conservative treatment. The role of the two-point discrimination (2PD) has not yet been evaluated as a potential indicator of severity during physical examination. Therefore, in our cross-sectional study, we aimed to find a correlation between 2PD values and disease severity, based on the gold-standard electromyography and electroneurography (EMG-ENG) and ultrasonography findings. We conducted a post-hoc analysis of prospectively assessed CTS patients for 2PD values. We analyzed the correlation between 2PD and EMG-ENG measurement results, patient characteristics, nerve ultrasonography, and relevant CTS questionnaires. CTS severity was determined by EMG-ENG results. The Pearson correlation was calculated between variables. The study included 81 patients. The three pre-determined EMG-ENG severity categories showed a significant correlation between both 2PD values and 2PD severity categories (r= 0.29 [0.07–0.48] and r= 0.26 [0.03–0.45]). Distal sensory latency and conduction velocity values correlated significantly with 2PD categories. However, the correlation coefficients (r= 0.25 [0.02–0.46] and r=-0.24 [-0.37–0.07]) were low. The 2PD severity categories showed no significant correlation with the severity assessed by nerve ultrasound (r=-0.07 [-0.38–0.25]). The 2PD values showed a significant correlation between the values of the Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire (r= 0.3 [0.06–0.51]). We concluded that the best cut-off value for differentiating severe from non-severe CTS was at the 9.5 mm 2PD cut-off value (sensitivity = 0.65 [0.45–0.81], specificity = 0.71[0.58–0.82], AUC = 0.71 [0.59–0.83]). There is a significant correla