Diagnosing Dynamic Scapholunate Instability with Computer Tomography

Overview

Scapholunate instability can result in debilitating pain, dysfunction, and secondary arthritis. If treatment is required, the instability should ideally be addressed in the dynamic stage, before non-reducible non-repairable deformation occurs. Early diagnosing of instability of the scapholunate joint can be a complex task. In this study, the use of computer tomography (CT) scan is evaluatedto reveal the dynamic characteristics of the scapholunate instability. A CT-scan will be performed of the non-stressed wrist and a CT-scan under loading to potentially visualize increase of dorsal scaphoid translation, which is considered as primary cause of dorsoradial radioscaphoid pain in the early stage of scapholunate instability.

Part 1: Assessment of the normal scapholunate stability with CT scan with and without loading in patients without symptoms of scapholunate instability 40 patients without scapholunate instability, with normal scaphoid shift test will be included. Radiographs of both wrists will be performed (anteroposterior view in pronation, clenched fist in pronation, ulnar deviation + clenched fist in supination and a sagittal view). Measurements will be the scapholunate, radiolunate, capitolunate angle and the radioscaphoid distance/angle. Then, they will undergo CT scan of both wrists without loading of the wrists (full pronation). Then, a CT scan of both wrists with loading of the wrists (supination, ulnar deviation and clenched fist) will be performed. Segmentation of the CT scans will be performed to be able to compare both CT scans. The measurements will be scapholunate distance, radioscaphoid distance, radiolunate distance, radioscaphoid rotation, radiolunate rotation and scapholunate rotation. Exclusion criteria: \<18 years, arthritis, previous wrist disorders Part 2: Assessment of the scapholunate instability with CT scan with and without loading in patients with symptoms of scapholunate instability 40 patients with scapholunate instability, with positive scaphoid shift test will be included. Radiographs of both wrists will be performed (anteroposterior view in pronation, clenched fist in pronation, ulnar deviation + clenched fist in supination and a sagittal view). Measurements will be the scapholunate, radiolunate, capitolunate angle and the radioscaphoid distance/angle. Then, they will undergo CT scan of both wrists without loading of the wrists (full pronation). Then, a CT scan of both wrists with loading of the wrists (supination, ulnar deviation and clenched fist) will be performed. Segmentation of the CT scans will be performed to be able to compare both CT scans. The measurements will be scapholunate distance, radioscaphoid distance, radiolunate distance, radioscaphoid rotation, radiolunate rotation and scapholunate rotation. MRI scan will be performed to reveal the ligament attenuation of the scapholunate complex. Treatment options will be proposed as usual: conservative (medication, physiotherapy) and surgery (arthroscopic capsuloligamentous repair). If arthroscopy is agreed, arthroscopic assessment of the ligamentous complex will be performed. Correlation of the CT findings will be performed with the MRI and arthroscopic findings. Exclusion criteria: \<18 years, arthritis, previous wrist disorders