Excess length of stay attributable to surgical site infection following hip replacement: a nested case-control study.

Objective: We estimated the impact of hip replacement-associated surgical site infection (SSI) on morbidity and length of stay.

Methods: This was a pairwise matched (1 : 1) case-control study nested in a cohort. All patients who underwent hip replacement from January 1, 2000, to June 30, 2004, were prospectively enrolled for the nested case-control design analysis and were monitored from the time of surgery until hospital discharge, including any patients readmitted because of infection.

Results: Among the 1,260 hip replacements performed, 28 SSIs were detected, yielding a crude SSI rate of 2.2%. The median excess length of stay attributable to SSI was 32.5 days (P<.001), whereas the median prolonged postoperative stay due to SSI was 31 days (P<.001). Deep-wound SSI was the type that prolonged hospital stay the most (up to 49 days). Of the patients who developed an SSI, 4 required revision surgery, for an SSI-related morbidity rate of 14.3%.

Conclusion: SSI prolongs hospital stay; however, although hospital stay is a rough indicator of the cost of this complication, to accurately estimate the costs of SSI, we would need to consider individual costs in a linear regression model adjusted for all possible confounding factors.