Stress displacement and surgical benefit in Beckmann 7-9 pelvic ring injuries: A retrospective multicenter analysis.

INTRODUCTION: We assessed whether stress-induced displacement identifies stability-indeterminate lateral compression type 1 (LC1) pelvic ring injuries in which surgical treatment is associated with fewer early adverse or ambulatory-decline outcomes.

METHODS: This multicenter retrospective cohort study was performed at eight Level I trauma centers. Skeletally mature patients with OTA/AO 61B2 LC1 pelvic ring injuries, Beckmann scores 7-9, and documented stress examination were included; follow-up duration was modeled as a covariate rather than used as an inclusion restriction. The primary outcome was a composite of all-cause mortality, non-elective hardware failure or revision, or worsening ambulatory category. Outcomes were compared between surgical and nonoperative management within displacement strata of less than 12 mm, 12-16 mm, and greater than 16 mm.

RESULTS: The primary analytic cohort included 187 patients (98 nonoperative, 89 operative); follow-up duration was modeled as a covariate. Surgical patients had greater median displacement than nonoperative patients (14.3 vs 5.8 mm; P < 0.001). The composite outcome occurred in 41 nonoperative patients (41.8%) and 21 operative patients (23.6%; P = 0.009). In the 12-16 mm stratum, events occurred in 6 of 11 nonoperative patients (54.5%) and 3 of 20 operative patients (15.0%), corresponding to a 39.5% absolute risk reduction, number needed to treat of 2.5, and Fisher exact P = 0.038; after adjustment for follow-up duration, operative management remained associated with lower odds of the composite outcome (odds ratio 0.20; 95% CI, 0.04-0.90; P = 0.037). In the conservative sensitivity cohort restricted to at least 90 days of follow-up (121 patients), the 12-16 mm absolute risk reduction was 33.3% (number needed to treat, 3.0; P = 0.139).

CONCLUSIONS: Surgical management of 12-16 mm stability-indeterminate LC1 injuries was associated with a statistically significant reduction in early composite outcome that persisted after adjustment for follow-up duration and attenuated in a conservative follow-up-restricted sensitivity analysis. The finding was statistically fragile and derived from a small stratum in a retrospective cohort; it is hypothesis-generating and requires prospective validation.

LEVEL OF EVIDENCE: Therapeutic Level III.