Risk factors for periprosthetic joint infection after primary artificial hip and knee joint replacements.

INTRODUCTION We aimed to explore the risk factors for periprosthetic joint infection (PJI) after primary artificial hip and knee joint replacements by performing a case-control study. METHODOLOGY The clinical data of patients receiving primary hip and knee joint replacements were retrospectively analyzed. The case group included 96 patients who suffered from PJI, comprising 42 cases of hip joint replacement and 54 cases of knee joint replacement. Another 192 patients who received joint replacement at the ratio of 1:2 in the same period and did not suffer from PJI were selected as the control group. Differences between the two groups were compared in regard to etiology, pathogen, blood type, urine culture, body mass index (BMI), surgical time, intraoperative blood loss, postoperative 1st day and total drainage volumes, length of hospitalization stay, and history of surgery at the affected sites. RESULTS Gram-positive bacteria were the main pathogens for PJI. The most common infection after hip joint replacement was caused by Staphylococcus epidermidis, which accounted for 38.10%, while Staphylococcus aureus was mainly responsible for the infection of knee joint (40.74%). High BMI, long surgical time, large postoperative drainage volume, long hospitalization stay, history of surgery at incisions, previous use of immunosuppressants, preoperative hypoproteinemia and superficial infection were independent risk factors (p < 0.05). CONCLUSIONS PJI after primary replacement was mainly caused by gram-positive bacteria, and patients with high BMI, long surgical time, large postoperative drainage volume, long hospitalization stay, history of surgery at incisions, previous use of immunosuppressants, preoperative hypoproteinemia and superficial infection were more vulnerable.