Do the Proximal Ulnar Angulations Have Correlations with Each Other? Anatomical Study and Review of the Literature.

Objective: The proximal ulna has a complex and unique architectural anatomy, therefore, its fractures are difficult to manage. This paper aimed to evaluate proximal ulnar angulations that contribute to the fixation and restoration of proximal ulna fractures in the Turkish population. Materials and Methods: This study was performed on 107 Turkish adult ulnae (55 right, 52 left) whose age and sex were unknown. The ulnar length (UL), proximal distance of varus angulation (PDVA), and widths at the point of varus angulation were measured with a digital caliper. The proximal ulna torsion angle (PUTA), varus angulation (VA), proximal ulna dorsal angulation (PUDA), articular angle (AA), and olecranon-diaphysis angle (ODA) were measured with a goniometer. The statistical analysis was carried out at the SPSS 21.0 program (IBM Corporation, Armonk, NY, USA). Results: The median UL was 251.97 mm (minimum: 196.84 - maximum: 497.76 mm), median PDVA was 82.7 mm (minimum: 16.21 - maximum: 108.62 mm), mean total width was 15.04±1.84 mm, mean posterior-interosseous width was 13.72±2.37 mm and mean posterior-anterior width was 15.15±1.93 mm. The mean PUTA was 27.10°±9.04°, the median VA was 14° (minimum: 5° - maximum: 23°), the median PUDA was 8° (minimum: -3° - maximum: 20°), the median AA was 25° (minimum: 19° - maximum: 39°), and the mean ODA was 17.39°±5.33°. A moderate negative correlation was detected between the PUDA and ODA (rs= -0.50, p<0.001). Conclusion: The mean proximal ulnar angulations in this study can be beneficial during surgery for the fixation of proximal ulna fractures. This study revealed the correlation between proximal ulnar angulations in the Turkish population.