Intraoperative evaluation of DRUJ instability through dorsal stress radiography in distal radius fractures

Certain type of injury of the triangular fibrocartilage complex associated with distal radius fracture can result in distal radioulnar joint instability (DRUJ). Untreated DRUJ instability may lead to poor result in the treatment of acute distal radius fractures. The aim of this study was to evaluate DRUJ instability in distal radius fractures through dorsal stress radiography comparing the affected and unaffected wrists intraoperatively. 49 patients with a distal radius fracture who were operatively treated with a volar locking plate were included. Dorsal stress radiography was used to evaluate both affected and unaffected wrists peri-operatively to detect DRUJ instability. Under general anesthesia, a dorsal stress test was performed on the unaffected wrist. Additionally, after fixation of the affected wrist, a dorsal stress test was performed. The ulnar translation ratio (UTR) was measured through the dorsal stress radiograph. Arthroscopic examination was performed on all affected wrists according to Palmer's and Atzei classification. The UTR of the affected wrist and the TFCC injury Palmer-type IB tendency were positively correlated (odds ratio: 1.18, p-value: 0.002). Additionally, as the UTR difference between the affected and unaffected wrists enlarged, it revealed a significant DRUJ instability tendency due to Palmer-type IB TFCC injury (p-value: 0.000006, Wilcoxon rank-sum test). Dorsal stress radiography is a reliable, simple procedure to evaluate DRUJ instability intraoperatively. UTR value from dorsal stress radiography could be useful for evaluating DRUJ instability associated with distal radius fracture.