The Novel Ulnar Nerve Coverage Method Which Has the Potential to Prevent the Postoperative Ulnar Neuropathy after Plate Fixation of Distal Humerus Fractures: Three Case Reports

INTRODUCTION: Postoperative ulnar neuropathy is still an unresolved complication in patients undergoing plate fixation of distal humerus fractures. We hypothesized that decreased blood flow to the ulnar nerve due to intraoperative procedures is an important factor in the development of postoperative ulnar neuropathy. We herein report three cases of distal humerus fractures in which the soft tissues surrounding the ulnar nerve were preserved as much as possible and finally not transferred anteriorly. Case Presentation. A 76-year-old woman, 82-year-old woman, and 34-year-old woman underwent plate fixation for distal humerus fractures. None of the patients developed postoperative ulnar neuropathy, and there were no complaints of numbness after postoperative day 1. Nerve conduction studies were performed after 3 months postoperatively and revealed that the motor nerve conduction velocities and compound motor nerve action potentials of the ulnar nerve in two of the three patients were higher than those of the noninjured side. In one of the three patients, these values were slightly lower than those of the noninjured side. All three patients achieved bony union after several months postoperatively. CONCLUSIONS: We obtained good outcomes with the ulnar nerve coverage method for preventing postoperative ulnar neuropathy in patients with distal humerus fractures. Preservation of blood flow to the ulnar nerve was considered important, and anatomical repositioning of the ulnar nerve after plate fixation has the potential to prevent adhesion between the ulnar nerve and the plate.