Stabilization of Scaphoid Fractures by 1 or 2 Headless Bone Screws

Abstract

Objective/Hypothesis: Scaphoid fractures are a rare and account only 2% to 3% of all fractures and 10% of all hand fractures. But they make up to 60% of all carpal fractures. In all, 70% to 80% of the blood supply of the scaphoid occur through terminal vessels of the radial artery. Due to its special anatomy and blood supply, Herbert and Fisher introduced in 1984, for the first time, the headless bone screw. Since then many studies were published with the aim to improve stability. So new screw designs were developed both biomechanically and clinically. Displaced scaphoid fractures are treated typically with headless bone screws, but a treatment with 1 screw will not lead to absolute stability. Due to the complex and multidirectional movements of the scaphoid, 1 screw is, specially against rotational forces, insufficient. Therefore, some authors started to use temporary antirotation k wires. Main aim of this study was to compare radiological outcomes between scaphoid fractured stabilized by 1 and 2 headless bone screws. So the null hypothesis was that there is no difference in healing rate between scaphoid fractures treated by 1 and 2 headless bone screws. Secondary aim of this study was to compare functional results between the groups. Materials and Methods: All B2 scaphoid fractures from January 2009 till February 2015 had been included in this study and analyzed retrospectively. Inclusion criteria were (1) stabilization by 1 or 2 headless bone screws, (2) B2 fracture of the scaphoid according to the classification of Herbert and Krimmer, and (3) existing preoperative computed tomography (CT) scan. Exclusion criteria included (1) additional injuries of the wrist and (2) prior existing wrist injuries. For statistical purposes, age, gender, cause of accident, and range of motion had been analyzed. As well, the last x-rays and CT scans were analyzed in respect of fracture healing, arthrosis, and complications. Results: Forty-five patients met inclusion criteria. Thirty-two had been stabilized by 1 and 13 by 2 headless bone screws. Mean interval between injury and surgery was 4 weeks and mean follow-up interval 7 months. At last follow-up, 12/13 (92%) healed in the group treated by 2 headless bone screws and 22/32 (69%) in the group stabilized by 1 screw. No differences in respect of range of motion were accounted. Conclusion: Stabilization of B2 scaphoid fractures by 2 headless bone screws lead to better healing rates than a stabilization by 1 screw with equally functional outcome.