MRI-Related Risk Factors for Distal Radioulnar Joint Instability

Instability of the dorsal radioulnar ligament (DRUL) is caused by multiple factors from bony and soft tissue structures. Studies of DRUJ instability based on MRI have rarely been reported. This study aims to investigate related instability factors in the distal radioulnar joint (DRUJ) after trauma based on MRI imaging.

The MRI imaging was performed on 121 post-traumatic patients with or without DRUJ instability from April 2021 to April 2022. All patients demonstrated pain or attenuated wrist ligamentous tissue quality with physical examination. The interesting variables, including age, sex, the distal radioulnar transverse shape, the triangular fibrocartilage complex (TFCC), DRUL, the volar radioulnar ligament (VRUL), distal interosseus membrane (DIOM), the extensor carpi ulnaris (ECU), and pronator quadratus (PQ), were analyzed using univariable and multivariable logistic regression model. The different variables were compared in radar plots and bar chart.

An average age of 121 patients was 42.16 ± 16.07 years. The 50.4% DRUJ instability existed in all patients and the distal oblique bundle (DOB) presented in 20.7% of patients. The TFCC (p = 0.03), present DIOM (p = 0.001), and PQ (p = 0.006) were identified to be significant in final multivariable logistic model. The percentage of patients with ligament injuries were general higher in DRUJ instability group. The patients with absent DIOM had a higher rate in DRUJ instability, TFCC, and ECU injury. There was higher stability in shape of C-type, intact TFCC, and present DIOM.

DRUJ instability is closely associated with TFCC, DIOM, and PQ. It could provide a potential for early detection of potential instability risk and taking necessary preventive measures.