gms | German Medical Science

Objectives/Interrogation: Radiographic characterization of the wrist in idiopathic carpal tunnel syndrome (CTS) patients has received little attention. To determine the radiographic characteristics of wrists in idiopathic CTS patients, we compared the radiographic parameters of the wrists between CTS patients and non-symptomatic controls.

Methods: Ninety-four wrists of 62 idiopathic CTS patients and 94 wrists of 94 asymptomatic controls were evaluated. The patients and controls were age/gender matched. CTS was diagnosed by clinical findings and nerve conduction studies. The lack of symptoms was confirmed with the medical record for the controls. Patients who had a history of osteoarthritis, rheumatoid arthritis, any upper extremity trauma or hemodialysis were excluded from both groups. X-ray images of the postero-anterior and lateral views of the wrist were taken by radiology technicians who were blinded to the clinical symptoms. The postero-anterior and lateral view were obtained with wrist neutral position. Using the obtained X-ray images, the indices of radial inclination (RI), ulnar variance (UV), volar tilt (VT), scapholunate angle (SLA), and transverse and antero-posterior diameters of the wrists were measured. The radiographic parameters were measured separately by two raters. Intraclass correlation coefficient (ICC) was evaluated for the inter-rater reliability. Average of the parameters of two raters measurements were compared between CTS patients and controls.

Results and Conclusions: The ICCs of the postero-anterior view parameters were 0.58, 0.77, and 0.99 for the RI, UV, and transverse diameter, respectively (P<0.01). The ICCs of the lateral view parameters were 0.60, 0.63, and 0.91 for the VT, SLA, and antero-posterior diameter, respectively (P<0.01). UV was significantly larger in the CTS patients compared to the controls (1.7 ± 1.8mm and 0.8 ± 1.5mm for the patients and controls, respectively, P<0.01). SLA was significantly smaller in the CTS patients compared with the controls (56.0 ± 8.8 degrees and 60.0 ±6.4 degrees for the patients and controls, respectively, P<0.01). There were no significant differences in the RI, VT, transverse and antero-posterior diameters.

In this study, significant differences in the ulnar variance and scapholunate angle were observed. This suggests that the imbalance of radioulnar bone length and the lower carpal tunnel height were characteristic factors of CTS. The results may be useful for identifying the preclinical conditions of CTS.