This radiographic study of 100 bilateral elbows quantifies the proximal ulna dorsal angulation (PUDA) — the natural dorsal bend in the proximal ulna. It establishes the PUDA's prevalence, magnitude, location, side-to-side symmetry, and measurement reliability to guide anatomic plate contouring during proximal ulna fixation.
Before this paper, the PUDA was not routinely quantified, and surgeons had no reliable data on its prevalence, magnitude, or symmetry to guide plate selection and contouring.
When you fix a comminuted proximal ulna fracture, nonunion, or malunion with a dorsal plate, obtain a contralateral lateral elbow radiograph. Measure the PUDA (expect ~5.7°) and the tip-to-apex distance (expect ~47 mm), then manually contour your plate to match — because most 'precontoured anatomic' plates are straight and will not reproduce this angulation.
In men, the tip-to-apex distance is significantly greater than in women (P =.001), so sex-matched contralateral templating is more precise than population averages alone. Malalignment of the PUDA during fixation risks radial head maltracking, proximal radioulnar joint incongruity, and abnormal forearm rotation. The consequences of getting this wrong are not subtle.
This radiographic study of 100 bilateral elbows quantifies the proximal ulna dorsal angulation (PUDA) — the natural dorsal bend in the proximal ulna. It establishes the PUDA's prevalence, magnitude, location, side-to-side symmetry, and measurement reliability to guide anatomic plate contouring during proximal ulna fixation.
Before this paper, the PUDA was not routinely quantified, and surgeons had no reliable data on its prevalence, magnitude, or symmetry to guide plate selection and contouring.
When you fix a comminuted proximal ulna fracture, nonunion, or malunion with a dorsal plate, obtain a contralateral lateral elbow radiograph. Measure the PUDA (expect ~5.7°) and the tip-to-apex distance (expect ~47 mm), then manually contour your plate to match — because most 'precontoured anatomic' plates are straight and will not reproduce this angulation.
In men, the tip-to-apex distance is significantly greater than in women (P =.001), so sex-matched contralateral templating is more precise than population averages alone. Malalignment of the PUDA during fixation risks radial head maltracking, proximal radioulnar joint incongruity, and abnormal forearm rotation. The consequences of getting this wrong are not subtle.