Diagnostic Use of Four-Dimensional Computed Tomography in Scapholunate Ligament Tear Detection.

Background: Wrist arthroscopy is widely used to assess the intactness of ligaments, including the scapholunate ligament (SLL), as it allows direct visualisation and palpation. However, arthroscopy is invasive and costly, while traditional imaging modalities, such as X-rays and MRI, often miss ligament injuries due to their static nature. A promising alternative is four-dimensional computed tomography (4DCT), which allows dynamic, non-invasive visualisation of wrist motion in real time. This study evaluates the diagnostic potential of 4DCT for detecting SLL tears by comparing its findings with arthroscopy and open surgery. Methods: Twenty-one patients with suspected SLL tears underwent 4DCT imaging, with independent reviews by two radiologists. The motion cycles of extension-flexion and radial-ulnar deviation were analysed. Arthroscopy was performed within a few weeks after the scan. Patients with Geissler grade III or IV tears underwent surgical reconstruction. The qualitative assessments of the SLL by radiologists and surgeons were compared, while the kinematic parameters of the injured and contralateral wrists were analysed using a linear mixed model. Results: Radiologists' 4DCT evaluations corresponded with arthroscopy or surgical findings in 14 of 21 patients (67%). Patients with total SLL tears showed greater scapholunate distance and scapholunate angle during all wrist movements compared with uninjured wrists. Notably, 4DCT showed greater diagnostic agreement with surgical findings than arthroscopy alone. Conclusions: These findings demonstrate the potential role of 4DCT in diagnosing SLL tears. Further research should focus on optimising the acquisition and analysis of the 4DCT scan and refining 4DCT parameters to distinguish partial from total SLL tears. Level of Evidence: Level III (Therapeutic).