Factors Associated With Failure of Superior Pubic Ramus Screws

Abstract

Objective: Examine factors associated with fixation failure in patients treated with superior intramedullary ramus screws. Design: Retrospective. Setting: Single, Level 1 trauma center. Patients: Unstable pelvic ring fractures amenable fixation that included superior intramedullary ramus screws. Intervention: Percutaneously inserted intramedullary superior ramus screw fixation of superior pubic ramus (SPR) fractures. Main Outcome Measurements: Loss of reduction (LOR) of the SPR fracture defined as >2 mm displacement on pelvic radiographs at any time point in follow-up. Results: Two hundred eighty-five fractures in 211 patients (age 44, 95% confidence interval 40.8%–46.4%, 59.3% women, 55.1% retrograde screws) were included in the analysis. 14 (4.9%) of fractures had LOR. Patients were significantly more likely to have LOR as age increased (P = 0.01), body mass index (BMI) increased (P = 0.01), and if they were women (P < 0.01). There was a significantly decreased LOR (P < 0.01) as fractures moved further from the pubis symphysis. Retrograde screws were significantly (P < 0.01) more likely to have LOR. In SPR fractures treated with retrograde screws, failure was significantly associated with increasing BMI (P = 0.02), the presence of an inferior ramus fracture (P = 0.02), and trended toward significance with increasing age (P = 0.06), and decreased distance from the symphysis (P = 0.07). Conclusions: Superior ramus screws are associated with a low failure rate (4.9%), which is lower than previously reported. Retrograde screw insertion, distance from the symphysis, increasing age, increasing BMI, decreased distance from the symphysis, and ipsilateral inferior ramus fractures were predictors of failure. In these patients, alternative modalities should be considered, although low rates of failure can still be expected. Level of Evidence: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Evaluation of cannulated compression headless screws as an alternative implant for superior pubic ramus fracture fixation: a biomechanical study

“…To address the high rate of reported implant related failure, the authors propose a new implant using secure and minimally invasive well-established techniques to stabilize pubic rami fractures by CCHS. There are known predictors of implant failure such as increased patients age and increased patients BMI, distance and decreased distance from the symphysis have been reported [27]. Increasing patient's age is typically associated with osteoporosis.…”

Variables associated with loss of fixation of retrograde rami screws in minimally displaced lateral compression type 1 pelvic ring injuries

“…Percutaneous screw fixation of pubic rami fractures is an effective, minimally invasive treatment option for unstable pelvic ring injuries. 1 However, retrograde placement of these rami screws has been shown to increase the risk of loss of fixation, which may be secondary to these screws being more commonly used for distal rami fractures where bony purchase can be limited. 1,2 Comminuted fractures of the distal rami, for which retrograde rami screws are most often used, have been shown to be a significant predictor of dynamic instability in patients presenting with minimally displaced lateral compression type 1 (LC1) pelvic ring injuries.…”

“…1 However, retrograde placement of these rami screws has been shown to increase the risk of loss of fixation, which may be secondary to these screws being more commonly used for distal rami fractures where bony purchase can be limited. 1,2 Comminuted fractures of the distal rami, for which retrograde rami screws are most often used, have been shown to be a significant predictor of dynamic instability in patients presenting with minimally displaced lateral compression type 1 (LC1) pelvic ring injuries. 3,4 Although fixation of these injuries remains controversial, anterior and posterior ring fixation is postulated to be beneficial over posterior-only fixation in a patient's early hospital course, facilitating mobilization and increasing the percentage of patients discharging to home compared with facilities.…”

“…5,6 Although anterior fixation may be beneficial, retrograde rami screw fixation of distal comminuted rami fractures, especially in the setting of elderly fragility fractures, can be challenging, and loss of fixation is not uncommon. 1 The purpose of this study was to evaluate variables associated with loss of fixation after retrograde rami screw fixation of stress-positive minimally displaced LC1 injuries. The identification of potentially modifiable risk factors may benefit future management of these injuries.…”

“…Percutaneous screw fixation of pubic rami fractures is an effective, minimally invasive treatment option for unstable pelvic ring injuries. 1 However, retrograde placement of these rami screws has been shown to increase the risk of loss of fixation, which may be secondary to these screws being more commonly used for distal rami fractures where bony purchase can be limited. 1,2…”