Evaluation of pisotriquetral motion pattern using four-dimensional CT: initial clinical experience in asymptomatic wrists

• PT joint AP interval measurements are larger at wrist flexion (vs. extension).
• PT joint CC excursion measurements are larger at wrist flexion (vs. extension).
• PT joint AP interval measurements had significantly high interobserver correlation.

AimTo characterise the normal motion pattern of the pisotriquetral (PT) joint during wrist extension and flexion, as well as observer performance of measurements using four-dimensional (4D)-computed tomography (CT) acquisitions and double-oblique multiplanar reconstruction (MPR) technique in asymptomatic contralateral joints of patients with unilateral wrist pain.Materials and methodsIn this Health Insurance Portability and Accountability Act (HIPAA)-compliant institutional review board-approved study, 4D-CT was performed on the asymptomatic contralateral wrists of 10 patients (mean age: 46 years; M/F: 6/4) for comparison to the symptomatic side. Two independent observers defined the “oblique–sagittal” plane for PT joint measurements. Measurements were obtained for the anteroposterior (AP) interval and craniocaudal (CC) excursion during the extension–flexion arc of wrist motion.ResultsThe median (interquartile range) of the AP interval was 0.65 mm (0.55–1 mm) in extension, 1.1 mm (0.8–1.82 mm) in the neutral position, and 4.65 mm (2.07–5.87 mm) in flexion. Likewise, the median of the CC excursions in asymptomatic wrists were 0 mm in extension, 0.27 mm (0–0.37 mm) in the neutral position, and 0.28 mm (0.18–0.31 mm) in flexion. The AP interval measurements obtained at wrist flexion were larger than measurements obtained at wrist extension. There was a strong consistency in AP interval difference measurements between the two observers (ICC=0.80; p<0.01); however, CC excursion difference measurements did not reach the significance threshold between the two observers (ICC=0.40; p=0.11).ConclusionPT joint kinematics in asymptomatic wrists demonstrates an increase in AP interval and CC excursion during wrist flexion. MPR techniques provide good interobserver agreements for AP interval measurements. The reported intervals for asymptomatic joints can be used as a reference for asymptomatic wrists.