Comparison of Bending Strength among Plate, Steinmann Pin, and Headless Compression Screw Fixations for Proximal Ulnar Shaft Fracture in Sawbones

Abstract

Purpose: Although plate osteosynthesis is commonly used to treat proximal ulna fracture, its treatment method is controversial because of complications such as large incision, long operation time, and soft tissue injury. Therefore, intramedullary headless compression screw (HCS) and Steinmann pin are considered as alternative treatment options. In this study, we aim to compare bending strength of plate and cortical screws, HCS, and Steinmann pin for proximal ulnar shaft fracture with sawbone. Methods: Transverse type fractures were made intentionally at the distal 7 cm from the proximal end of ulna sawbones and fixated with plate, HCS, and Steinmann pin after reduction. Three-point bending tests were performed with total of 21 sawbones, seven pieces for each group. Results: Average ultimate bending strength for each group was as follows; 521.7N for plate fixation group, 706.4N for HCS fixation group, and 812.6N for Steinmann pin fixation group. Statistically significant results were observed among the three groups (p<0.01). When two groups were compared separately, Steinmann pin fixation and plate fixation (p<0.01), Steinmann pin and HCS fixation (p=0.047) showed statistical significance. There was a significant trend between HCS and plate fixation group (p=0.064).Conclusion: HCS and Steinmann pin fixation showed higher bending strength when compared to plate fixation for proximal ulnar shaft fracture in sawbone. Although further studies are needed, HCS and Steinmann pin fixation are promising fixation methods that may be used as an alternative to plate fixation.