Incidence and Risk Factors for Health-Care Associated Infections after Hip Operation

Hip operation reduces pain and improves mobility and quality of life for more than 300,000 people annually, most of whom are more than 65 years old. Substantial increases in surgical volume are projected between 2005 and 2030 in primary total (174%) and revision (137%) procedures. This projection demands that the impact of increasing age on the relative risk of health-care associated infections (HAI) after hip surgical procedures be assessed. Our aim was to examine the incidence and risk factors of HAI among patients who underwent hip operations between 2006 and 2012.

This secondary analysis included data from patients 18 years old or older and having a hip prosthesis procedure in three New York City hospitals between 2006 and 2012. Procedures were categorized as total or partial hip replacements or revision and re-surfacing procedures. Outcomes of interest were blood stream infections (BSI), urinary tract infections (UTI), or surgical site infections (SSI). Patients in whom an infection developed during the hospital visit in which the hip procedure occurred were counted as cases.

Of 2021 patients, approximately 11% (n = 218) had an HAI. There was no difference in infection rates by admission year despite an increase in surgical volume. SSI was associated with younger age, previous hospitalization, and hip revision surgical procedure whereas UTI and BSI were associated with older age, greater co-morbidity, longer pre-operative length of stay and intensive care unit stay, (p < 0.05).

HAI after hip operation affected approximately one in 10 patients over a 7-year period in three high-volume hospitals. SSI occurred least frequently, predominantly among patients who underwent revision surgery (without previous SSI), were younger, and had a history of previous hospitalization. Infections such as BSI and UTI, although rare, occurred more frequently and in patients with more co-morbidities, longer pre-operative length of stay, and who required higher level care. Further research to understand these unexpected findings and target interventions is warranted.