Union and displacement characteristics following percutaneous screw fixation of superior pubic rami fractures

Purpose To determine union and displacement metrics following percutaneous screw fixation (antegrade or retrograde) of superior pubic rami fractures. Methods This is a retrospective cohort study from a single level 1 trauma center. Skeletally mature patients with at least one superior pubic ramus fracture present as part of a lateral compression-type pelvic ring injury were included. Results Eighty-five (85) patients with 95 superior pubic rami fractures met the study’s inclusion criteria. LC1, LC2, and LC3 injuries occurred in 76.5%, 15.3%, and 8.2% of patients, respectively. The majority of patients underwent concurrent posterior pelvic ring fixation (94.1%). Superior ramus screw placement occurred predominantly via retrograde technique (81.1%) with cannulated screws of size 6.5 mm or larger (93.7%). Of the 95 eligible fractures, 90 (94.7%) achieved union at a mean of 14.0 weeks (7–40 weeks). Of these united fractures, 69 (76.7%) healed with no measurable displacement, while the remaining 23.3% healed with residual mean displacement of 3.9 mm (range: 0.5–9.0 mm). Multivariable analysis demonstrated a positive association between age ( p = 0.04) and initial displacement ( p = 0.04) on the final degree of residual displacement at union. A Kaplan–Meier survival analysis identified increased age to be significantly related to increased time to union ( X 2 (2) = 21.034, p < 0.001). Conclusions Union rates following percutaneous screw fixation of superior pubic rami fractures associated with lateral compression-type pelvic ring injuries approach 95%. Though minimal in an absolute sense, increasing age and a greater degree of initial displacement may influence the final degree of residual displacement at union. Level of evidence IV.