[Morphology of ulnar trochlear notch and defining ideal position for olecranon osteotomy].

Aim: The aim of the study was to calculate the most important parameters of ulna and to determine its gender. Classifying trochlear notch joint surface types and to establish their representation in Serbian population. To determine the ideal position for olecranon osteotomy.

Material and methods: The study included 69 bones. Gender determination was performed using digital scale and photographs of the ulna. The bones weight, maximum and physiological length were measured. The place for the ideal position of olecranon osteotomy (projection of the bare area on its posterior wall) was determined on profile images.

Results: Gender related, 45 (65.21%) bones belonged to males, 24 (34.79%) ulnas belonged to females. Type I of the bare area was present in 38 (55%) ulnas, type II in 20 (29%), whereas type III was present in 11 (16%) bones. The average value for the ideal position of olecranon osteotomy was 23.02 mm. In males' ulnas, it was 23.22 mm, in females, it was 22.59 mm.

Conclusion: Type I of the bare area is the most common type of trochlear notch joint surface in Serbian population. The average value for the ideal position of olecranon osteotomy was 23.02 mm. We believe that a uniform name for the bare area should be established.