gms | German Medical Science

Objectives/Interrogation: Unstable distal radius intra-articular fractures require restoration of alignment, and exact fixation of intra-articular fragments is essential. Here, we employed intraoperative computed tomographic (CT) navigation to accurately insert screws in the intra-articular dorsal fragments during treatment with a volar locking plate for distal radius intra-articular fractures. We evaluated the accuracy of this procedure through preoperative, intraoperative, and post-bone union CT findings as well as the clinical outcomes.

Methods: This study included 18 patients with distal radius fractures, who were treated with a volar locking plate (HYBRIX, Mizuho, Tokyo, Japan) using intraoperative CT (SOMATOM Definition AS, Siemens, Erlangen, Germany) navigation (Kolibri, Brainlab, Feldkirchen, Germany) with a minimum follow-up duration of 12 months. The mean patient age was 60.8 years and the mean follow-up duration was 16.2 months. Based on the AO comprehensive classification of distal radius fractures, 3 cases were classified as C1, 7 as C2, and 8 as C3. We examined the articular displacement and position of the inserted distal screws on CT images. The gap and step off were calculated as the indices of articular displacement. The mean minimum distance between the screw and articular surface and between the tip of the screw and the dorsal cortex were calculated. The three distal ulnar screw positions that influence the stability of the ulnodorsal articular fragment were evaluated. The Mayo wrist score and DASH score were also clinically evaluated.

Results and Conclusions: The mean gap and step off were 3.1 and 1.6 mm preoperatively, 0.9 and 0.3 mm intraoperatively, and 0.3 and 0.3 mm post-bone union, respectively. The mean distances between the screw and articular surface were 1.2, 1.7, and 1.7 mm from the ulnar side intraoperatively and 0.9, 1.3, and 1.4 mm from the ulnar side post-bone union. The mean distances between the tip of the screw and the dorsal cortex were 1.1, 0.5, and 0.9 mm from the ulnar side intraoperatively and 0.9, 0.2, and 0.6 mm from the ulnar side post-bone union. At the final follow-up, the mean Mayo wrist score was 91.7 and the mean DASH score was 6.5.

CT evaluation revealed that the screws were precisely inserted for articular fragments and bone union was achieved, thereby maintaining good intra-articular alignment. The findings demonstrate the accuracy of volar locking plate fixation assisted by intraoperative CT navigation and the good clinical outcomes of this procedure.