This is an anatomic study designed to understand the morphology of the proximal ulna. Thirty-one cadavers were analyzed using CT scans. The posterior and lateral offsets increased distally from the articulation center and the mean diameter of the canal was larger in males than in females. The average valgus angulation was 8 degrees for males and 7 degrees for females.
The significance of this article is that longer stemmed ulnar implants may require a modular design in order to meet the anatomic constraints during implant positioning to avoid inadvertent perforation of the shaft of the ulna distally as the implants are placed.