The impact of varus angulation on proximal fractures of the ulna

Abstract

BackgroundWe 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.MethodsWe 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.ResultsThe 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).ConclusionsThe 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.

Proximal ulna fractures in adults: A review of diagnosis and management

“…Although the overall alignment at the elbow in the coronal plane is valgus, the proximal ulna has a mean varus angulation 4 of 8.48 and the inability to restore it adequately during surgery leads to an average 6 loss of range of motion (ROM) at the elbow and 6.2 loss of forearm rotation. 5 In the sagittal plane the ulna demonstrates a gradual dorsal bow, which has been termed proximal ulna dorsal angulation (PUDA). Inability to restore PUDA to within 5 of the normal leads to an overall loss of 18.62 of ROM in the flexion-extension plane 6 and may also result in radial head subluxation.…”

Clinical anatomy and biomechanics of the elbow

“…The average value ranges from 8.48 to 17.7 . 3,5,6,23,24 Mark Morrey of the Mayo Clinic, USA has described it as the "rule of 8" meaning 8 radial bow approximately 8 cm from the tip of the olecranon (personal communication). The apex of varus angulation and the dorsal angulation expressed as distance from the tip of olecranon can only be served as a reference.…”

Olecranon Fractures

“…It is also important to reconstruct the anteromedial angulation which is commonly known as the varus angle (VA). A malreduced VA can lead to loss in elbow extension/flexion and pronation/supination ROM 16 . This is more important with an intramedullary (IM) screw or straight plate osteosynthesis (PO) which can lead to malreduction and opening at the fracture site.…”