Periprosthetic hip and knee infections: comparison of etiology, perioperative management and costs.

OBJECTIVE: We compared two series of patients treated at our Hospital for periprosthetic hip and knee infections (PHI; PKI), in order to evaluate etiology, perioperative management (duration of spacer, antibiotic therapy, quality of life during the treatment), length of hospital stay, and costs. PATIENTS AND METHODS: We included in the study 32 patients with PHI and 30 patients with PKI. The average age of the patients was 74.8 in PHI and 71.2 in PKI. Treatment consisted of a two-stage revision associated with antibiotic therapy. All patients were followed up for at least two years after surgery. We analyzed the causative microorganism responsible for the infection, duration of the spacer and antibiotic therapy, quality of life during this time, length of hospital stay, and total hospital cost of treatment. RESULTS: The gram-negative microorganisms were more common in PHI, without any statistically significant difference compared to PKI. Duration of the spacer for PHI was 7.4 months and 5.5 months for PKI (p=0.005). Length of antibiotic therapy was 6.2 months for PHI and 4.1 months for PKI (p<0.001). Most patients in the two series had an acceptable quality of life during treatment. The mean length of hospitalization was 54 days in PHI and 26 days in PKI (p<0.001). The cost averaged 38,300 euros for PHI and 22,100 euros for PKI (p<0.001). CONCLUSIONS: Our study showed statistically significant differences between periprosthetic hip and knee infections as regards etiology, duration of treatment and global costs. Periprosthetic hip infections are caused by more virulent microorganisms that are harder to eradicate, require a longer length of treatment and have a greater economic impact on the healthcare system.