Fibromyalgia Is Associated with Increased 90-Day Readmission and Surgical Escalation After Elective Primary Total Hip Arthroplasty

Purpose: : Fibromyalgia is a chronic pain syndrome characterized by central sensitization and frequent comorbidity clustering. Its impact on early readmission and surgical escalation after elective primary total hip arthroplasty (THA) remains incompletely defined in contemporary nationwide data. We evaluated the association between fibromyalgia and 90-day readmission, revision, and reoperation after elective primary THA. Methods: We performed a retrospective cohort study using the Nationwide Readmissions Database (NRD) 2020-2022. Elective primary THA hospitalizations were identified and restricted to procedures performed on hospital day 0. Fibromyalgia status was defined using ICD-10-CM diagnosis coding. Baseline demographics and comorbidities were compared in the unmatched cohort. To improve comparability, we performed 1:5 propensity score matching without replacement. Covariate balance was assessed using standardized mean differences (SMD), with adequate balance defined as SMD < 0.1. Outcomes included index hospitalization complications, all-cause 90-day readmission, and readmission-associated surgical outcomes including true component-level revision, hip-related reoperation, and any inpatient procedure during readmission. Readmission diagnoses were summarized and standardized per 10,000 procedures. Results: Among 366,374 elective primary THA hospitalizations, 7,868 patients (2.1%) carried a diagnosis of fibromyalgia. Patients with fibromyalgia were younger than those without fibromyalgia (65.72 ± 9.86 vs 67.08 ± 10.83 years; mean difference 1.36 years, 95% CI 1.12-1.60; p<0.001) and were predominantly female (94.3% vs 55.5%, p<0.001). After 1:5 propensity score matching without replacement, 46,126 patients remained (7,868 fibromyalgia; 38,258 controls) with SMD < 0.1 across matched covariates. During the index hospitalization, fibromyalgia was associated with higher rates of blood loss anemia (20.0% vs 16.5%; OR 1.27, 95% CI 1.19-1.35; p < 0.001), blood transfusion (3.5% vs 2.8%; OR 1.25, 95% CI 1.09-1.43; p = 0.001), pulmonary embolism (0.2% vs 0.1%; OR 2.21, 95% CI 1.20-4.08; p = 0.009), sepsis (0.2% vs 0.1%; OR 1.84, 95% CI 1.00-3.41; p = 0.048), and urinary tract infection (1.3% vs 1.1%; OR 1.25, 95% CI 1.01-1.55; p = 0.042). Ninety-day readmission occurred in 7.4% of patients with fibromyalgia compared with 5.0% of matched controls (OR 1.533, 95% CI 1.393-1.687; p < 0.001). During readmission, fibromyalgia was associated with increased odds of true component-level revision (1.6% vs 1.0%; OR 1.526, 95% CI 1.245-1.871; p < 0.001), hip-related reoperation (1.9% vs 1.4%; OR 1.367, 95% CI 1.136-1.645; p = 0.001), and any inpatient procedure (4.9% vs 3.4%; OR 1.483, 95% CI 1.321-1.666; p < 0.001). Conclusions: In a nationwide propensity-matched cohort of elective primary THA, fibromyalgia was associated with higher 90-day readmission and higher rates of readmission-associated surgical escalation, including component-level revision and reoperation. These findings support targeted perioperative optimization and closer early follow-up for patients with fibromyalgia undergoing elective primary THA. Levels of Evidence: Level III