Background: We studied anteromedial varus angulation (VA) in the proximal third of the ulna. The importance of restoration of the anatomical orientation of the ulnar after a proximal fracture is unclear. The purpose of this study was to evaluate the impact of minimal proximal ulna malunion on elbow function after a proximal ulna fracture.
Methods: We reviewed the follow-up of 60 patients who had undergone open reduction with internal fixation (ORIF) of a proximal fracture of the ulna. Patients were divided into two groups, defined as either more or less than 5° of the difference between the VA of the fractured and contralateral ulna. The range of motion(ROM)of elbow flexion, extension and forearm rotation on both sides, Mayo Elbow Performance Score (MEPS) and Visual Analogue Scale (VAS) were measured.
Results: The average postoperative time was 3.1 years (1-5 years). Mean VA of the fractured arm was different from the normal side (7.8 ± 3.0 vs 12.7 ± 3.0). Compared to the unfractured arm there was a loss in mean elbow flexion (14.2 ± 4.9 vs 18.0 ± 5.9), extension ROM (7.1 ± 2.5 vs 9.3 ± 1.9, p < 0.05) and forearm rotation ROM (15.6 ± 8.6 vs 21.8 ± 9.5) that were statistically significant (p < 0.05). There were no statistically significant differences in the MEPS and VAS score results between the two groups (p > 0.05).
Conclusions: The function of the elbow and forearm was restricted after VA malunion in the proximal ulna, but the quality of life of these patients had not been significantly affected. We suggest that orthopedic surgeons should assess whether the specialized structures of the proximal ulna are damaged or not before surgery. If the anatomy of the fractured bone cannot be restored through manipulation of the connected end directly, it is better to image the anatomical structure of the healthy side from using an elbow X-ray before surgery, and then reset using a pre-shaped plate to prevent malunion.
Keywords: Malunion; Proximal fractures of the ulna; Varus angulation.