The utility of routine cultures, cell count, and crystal evaluation of aspirate from aseptic olecranon bursitis

BACKGROUND: Aspiration of the olecranon bursa is a treatment option for acute olecranon bursitis (OB). Typically, the aspirate is sent for microbiologic analysis, cell count, and crystal analysis. This study investigates the utility of fluid aspirate analysis from patients with clinically diagnosed aseptic OB. METHODS: In this prospective study (IRB #i20-00986), patients presenting with acute aseptic OB were treated with aspiration as standard of care. Patients consented to participate in this study via phone. Patients with suspected infectious bursitis, open draining wound, and chronic OB were excluded. The aspirate was sent out for routine microbiologic analysis (aerobic and anaerobic cultures and Gram staining) and fluid analyses, including cell count with differential and crystal analysis. Nucleated and differential cell count was reported as absolute numbers per cubic millimeter and percentage, respectively. Compression wrap was applied after OB aspiration, and patients were asked to ice and take anti-inflammatory medications. Clinical follow-up was done after 6 weeks and at 3 months for resolution vs. recurrence of symptoms, and the mean time to resolution was reported. RESULTS: A total of 26 patients (28 cases) with aseptic OB were enrolled in this study. Two patients had bilateral OB. The mean time to aspiration after the onset of symptoms was 26.4 days. One patient had recurrence of swelling after the first aspiration and underwent repeat bursa aspiration. No organisms were isolated or reported on Gram staining on any of the aspirate samples. Two aspirates were reported positive for calcium pyrophosphate dihydrate crystals. No patient had monosodium urate crystals. All patients had resolution of swelling and symptoms without the development of postaspiration infection. CONCLUSIONS: This study demonstrates limited clinical utility of routine microbiologic analysis (cell count, microbiologic, and crystal evaluation) of fluid aspirate from clinically diagnosed aseptic OB. Although 7% of fluid aspirates were positive for calcium pyrophosphate dihydrate crystals, it did not change the overall treatment.