Is the use of Porous Threaded Titanium Implants Associated with Lower Rates of Implant Migration in Elderly Pelvic Ring Injuries?

OBJECTIVES: To determine if porous threaded titanium implant (PTTI) screws placed in the posterior pelvic ring as iliosacral (IS) or transiliac-transsacral (transsacral) were associated with implant positional changes, alterations in postoperative weightbearing restrictions, or the necessity of revision surgery in operatively managed geriatric pelvic ring injuries, compared to standard stainless steel screws.

DESIGN: Retrospective cohort study.

SETTING: Academic Level I trauma center.

PATIENT SELECTION CRITERIA: Patients with operatively managed pelvic ring injuries (AO/OTA61) from January 2017 to June 2025, aged ≥65 years with a minimum of 6-months of radiographic and clinical follow-up were included.Outcome Measures and Comparisons: The primary study outcome was the incidence of postoperative pelvic ring implant positional changes, ≥2mm from immediate postoperative radiographs compared among patients treated with PTTI versus standard stainless steel screws for IS and transsacral fixation. Secondary outcomes included subsequent revision surgery or alterations in postoperative weightbearing restrictions related to implant positional changes. A multivariable logistic regression was used to determine associations of demographic, injury, and treatment variables with implant positional changes, the necessity for revision surgery, or negative changes in postoperative weightbearing restrictions.

RESULTS: 271 patients were included; 215 (79.3%) were managed with standard screws, while PTTIs were used in 56 (20.7%). The standard screw cohort had a median follow-up of 8.9 months (interquartile range 6.2-11.3 months), while the PTTI cohort had a median follow-up of 9.1 months (interquartile range 6.3-10.9 months). Compared with the standard screw cohort, the PTTI cohort had a higher proportion of female sex (57.2% versus 73.2%, respectively; p=0.029) and a higher average age (74.0 years versus 78.6 years, respectively; p<0.001).Radiographic migration ≥2mm for posterior implants was observed in 18.1% of patients in the standard implant cohort versus 0.0% in the PTTI cohort (p<0.001). Implant migration >1cm was observed in 3.7% of patients in the standard implant cohort versus 0.0% in the PTTI group (p=0.231). The implant positional changes resulted in negative weightbearing restriction changes in 9 of 215 (4.2%) patients in the standard implant cohort compared with 0 of 56 in the PTTI cohort (p=0.120). Of the patients with standard implants, 9 (4.2%) underwent revision for posterior implant loosening, compared with 0 (0.0%) in the PTTI cohort.On multivariate analysis, posterior implant positional changes were associated with a protective effect from PTTI and anterior ring fixation (OR 0.1, 95% CI 0.0-0.7, p=0.023 and OR 0.2, 95% CI 0.1-0.4, p<0.001, respectively). The necessity for revision surgery or negative change in postoperative weightbearing restrictions was not significantly associated with PTTI use (OR 0.3, 95% CI 0.1-1.3, p=0.106).

CONCLUSIONS: In geriatric pelvic ring injuries, PTTIs had no migration after placement and were associated with a lower incidence of any implant positional change and posterior implant positional changes.

LEVEL OF EVIDENCE: Prognostic Level III.