Acute trochanteric bursitis as an early complication of lumbosacral fusion: Incidence, risk factors, and therapeutic response.

BackgroundTrochanteric bursitis is an underrecognized cause of early postoperative lateral hip pain following lumbosacral fixation and may mimic radicular pain. Acute postoperative bursitis and its metabolic-mechanical determinants remain poorly characterized.MethodsA total of 310 patients who underwent lumbosacral fixation (2020-2024) were screened; 37 (11.9%) developed first-week lateral hip pain. After applying exclusion criteria, 30 magnetic resonance imaging (MRI)-confirmed acute trochanteric bursitis cases were age- and sex-matched 1:1 with 30 controls. Vitamin D, femoral neck T-scores, trochanteric Hounsfield units (HU), and a Composite Bone Quality Index (CBQI) were recorded. Outcomes were assessed using the Visual Analog Scale (VAS) and Harris Hip Score (HHS) at baseline, 3 months, and 12 months. Additive interaction analysis evaluated CBQI-BMI synergy. Receiver operating characteristic (ROC) analysis was used to determine the CBQI threshold.ResultsHigher BMI, lower vitamin D, reduced HU, and lower T-scores were associated with bursitis. CBQI demonstrated good discriminatory ability (area under the curve [AUC] 0.84; cut-off -0.50). Low CBQI combined with high BMI showed a supra-additive interaction. High-CBQI/low-BMI patients improved rapidly, whereas low-CBQI/high-BMI patients showed delayed recovery but achieved similar 12-month outcomes.ConclusionAcute postoperative trochanteric bursitis is influenced by both metabolic bone fragility and mechanical load. CBQI and BMI may help characterize high-risk phenotypes and early clinical trajectories. Preoperative assessment of vitamin D, HU-based bone density, and BMI may support risk stratification and targeted perioperative management.