Clinical implications of additional posterior fractures in combined anterior-posterior pelvic ring fractures in elderly patients

Objectives: Historically, pelvic ring fractures (PRF) are considered to occur predominantly in the anterior ring and therfore to be mechanically stable. Combined anterior and posterior (A + P) PRF are expected to be less mechanically stable and therefore to be associated with higher levels of pain and reduced mobility compared to isolated anterior fractures. The current study investigates the clinical relevance of combined A + P PRF in elderly patients. Methods: A prospective multicentre cohort study was conducted in patients >70 years of age with anterior PRF after low-energy trauma diagnosed on conventional radiographs. All patients underwent an additional CT-scan. Patients were divided into two groups; isolated anterior or combined A + P fractures. Patients were treated conservatively with adequate analgesia for at least one week. If patients could not be mobilised after conservative treatment, surgical fixation was performed. Numerical Rating Scale (NRS) pain scores, dependence on walking aids and Activities of Daily Living scores (ADL) were measured at 2-4 weeks, and 3, 6 and 12 months after fracture. Results: 102 patients (age 81.1 & PLUSMN; 7.6 years) were included. Isolated anterior fractures were diagnosed in 25 (24.5%) and A + P fractures in 77 (75.5%) patients. Baseline characteristics did not differ between the two groups. Most patients were successfully treated conservatively and 5 (4.9%) underwent percutaneous trans-iliac, trans-sacral screw fixation after failure of conservative treatment. At 2-4 weeks post trauma, patients with A + P fractures had similar median pain scores (3 (range 0-8) vs. 5 (0-10), p = 0.19) and ADL scores (85 (25-100) vs. 78.6 (5-100), p = 0.67), but were more dependent on walking aids (92.8% vs. 72.2%; p = 0.02) compared to patients with isolated anterior fractures. There were no significant differences at 3 months. At one year follow-up the median NRS pain and ADL scores for both fracture groups were 0 and 100, respectively. Mortality was 10.8%, and additional loss to follow-up was 17.6%. Conclusions: The vast majority of elderly patients with PRF have combined A + P fractures. The clinical implications of additional posterior pelvic ring fractures in elderly patients appears to be limited.