Does surgical treatment for unstable fragility fracture of the pelvis promote early mobilization and improve survival rate and postoperative clinical function?

Purpose: This retrospective multicenter study aimed to compare rates of early mobilization and survival and functional outcome of surgical treatment (S) with that of conservative treatment (C) according to each unstable fragility fracture of the pelvis (FFP) classification type with displacement of the posterior component ≥ 5 mm. Methods: We analyzed 64 patients with unstable type III and IV FFP who could move and transfer themselves before injury and had ≥ 5 mm displacement of the posterior component. We compared survival rate, early mobilization, walking ability at final follow-up, and complications at admission for each type of surgical and conservative treatment. Results: Most of the unstable FFP were type IIIa and IVb in the study population. Type III comprised 40 cases (group S:13/group C:27) and type IV comprised 24 cases (group S:7/group C:17). There were no significant differences in 3 month and 1 year survival rates, although group C (III) had the tendency of higher mortality rate (p = 0.08). Mobilization (transferring to a wheelchair) was enabled significantly earlier in group S (III) than in group C (III) (p = 0.02), but in type IV, most patients enabled early mobilization even without surgical intervention. There were no significant differences in hospital complications and walking ability at final follow-up. Conclusion: In this study, the superiority of surgical treatment for unstable FFP was not proven. However, the results suggest that type IVb may be a relatively stable type compared to type III and that type IVb should be considered separately from bilaterally complete unstable sacral fractures due to high-energy trauma.