Cutibacterium Culture Isolation Following Total Hip and Total Knee Arthroplasty

Introduction Cutibacterium species, common commensal gram-positive bacteria, present a diagnostic challenge for arthroplasty surgeons. While Cutibacterium infections have been well characterized in shoulder surgery, their presentation and clinical significance in total hip (THA) and total knee arthroplasty (TKA) remain less understood. Methods A retrospective chart review identified patients with positive Cutibacterium cultures following THA or TKA. Demographics, laboratory values, and microbiologic data were collected. Statistical comparisons were performed using t-tests and chi-squared analysis. One-year outcomes were evaluated using the MSIS ORT criteria among patients undergoing further surgical intervention. Results Twenty-nine patients with Cutibacterium-positive cultures were identified (21 THA, 8 TKA); 15 (52%) were polymicrobial. Ten THA patients (47.6%) and seven TKA patients (87.5%) met MSIS criteria for infection. Mean time to culture positivity was similar between THA (6.8 days) and TKA (7.4 days; p = 0.57). Sonication cultures were positive in 24% of THA and 12.5% of TKA cases. Mean ESR was 36.4 mm/h for THA and 51.5 mm/h for TKA (p = 0.21); mean CRP was 35.2 and 36.8 mg/dL, respectively (p = 0.95). Mean synovial cell counts were 27,055 for THA and 22,194 for TKA, with PMN percentages of 68% and 73.9% (p = 0.72, 0.70). Monomicrobial infections demonstrated a mean cell count of 24,143 with 58.9% PMNs, compared to 25,903 and 78.8% in polymicrobial cases. At one year, 72% of patients undergoing subsequent surgery achieved successful outcomes. Higher ASA classification was the only significant predictor of failure (mean 3.0 vs. 2.75). Conclusion Cutibacterium-associated THA and TKA infections often present with delayed culture growth, mild inflammatory markers, and frequent polymicrobial involvement. Most patients experience favorable outcomes following surgical management, though greater medical comorbidity may predict treatment failure.