Comparison between navigated and conventional percutaneous screw fixation of non-displaced scaphoid fractures

Abstract

Incorrect screw placement and penetration in screw fixation of scaphoid fractures are found in 5 to 30 %. Therefore, optimizing of screw placement is desirable, especially because an exact central position of the screw in the proximal fragment leads to a significant higher stability as a more peripheral position. 36 patients with an acute non-displaced scaphoid fracture were included in this randomized prospective study. 18 patients underwent navigated, the other 18 conventional percutaneous screw fixation of an acute non-displaced scaphoid fracture through a dorsal approach. Operation time and x-ray dose were measured. In both groups the position of the screw in the scaphoid was calculated on CT scans and compared with each other. Clinically, 17 patients with navigated and 11 with conventional percutaneous screw fixation with an average age of 52 resp. 43.2 years were available for follow-up examination including Krimmer- and DASH-score. All scaphoids healed within an adequate time. Two cases of navigated screw fixation have been converted to conventional percutaneous screw fixation. The average operation time in the navigated group was 83.2 minutes, in the conventional group 42.1 minutes. X-ray dose measured 106,5 ± 19,9cGy/cm2 in the navigated group and 45,6 ± 8,0cGy/cm2 in the conventional group. Screw penetration using an intraosseous compression screw (HSC) was observed in 5 conventionally fixed scaphoids, 4 distally (2,27 ± 1,47 mm), 1 proximally. In the navigated group there were 11 screw penetrations, 4 proximally (2,01 ± 0,81 mm) and distally (1,21 ± 0,64 mm), 3 distally (1,18 ± 0,44 mm), and 4 proximally (1,61 ± 0,57 mm). Axial screw position was more accurate in the conventional group. The 17 navigated patients averaged a Krimmer-Score of 83.6 and a DASH-score of 5,6 points at follow-up. The 11 conventional treated patients averaged a Krimmer-Score of 95 and a DASH-score of 8.0 points at follow-up. In this study navigated screw fixation of acute non-displaced scaphoid fractures was not superior to conventional percutaneous screw fixation, neither for screw position, screw penetration nor with respect to the clinical outcome.