Establishment and validation of a nomogram model for periprosthetic infection after megaprosthetic replacement around the knee following bone tumor resection: A retrospective analysis.

BACKGROUND

Due to the particularity of patients with bone tumors, the risk of periprosthetic infection following megaprosthetic replacement is much higher than that of traditional total knee arthroplasty. Unfortunately, few studies specifically reported the risk factors for periprosthetic infection following megaprosthetic replacement. The purposes of the study were to (1) establish a nomogram model, which can provide a reference for clinicians, and patients to reduce the occurrence of periprosthetic infection (2) explore the risk factors for deep infection of megaprosthesis.

HYPOTHESIS

A prediction model can be established and has favorable predictive accuracy.

PATIENTS AND METHODS

One hundred and seventy-seven megaprostheses were identified. There were 61 female patients and 116 male patients with a mean age of 35 years. The following risk factors were analyzed: tumor site, sex, age, material for prosthetic stem, tumor type, smoking, diabetes, length of bone resection, operation time, chemotherapy, BMI, malignant tumor staging and hematoma formation. Finally, based on the multivariate analysis, the independent risk factors were used to develop a nomogram model.

RESULTS

Univariate Cox regression analysis showed that the chemotherapy, longer operation time and hematoma formation were risk factors for periprosthetic infection. Multivariate Cox regression analysis showed that the chemotherapy, longer operation time and hematoma formation were significant risk factors for periprosthetic infection. The nomogram model was established using these significant risk factors, with a C-index of 0.766 and an acceptable consistency according to the internal validation, indicating that the prediction model had favorable predictive accuracy.

DISCUSSION

This study has important implications for the future investigations of prevention of periprosthetic infection. The nomogram model identifies high-risk patients for whom attached prophylaxis measures are required. Future studies regarding reduction of incidence of periprosthetic infection should pay close attention to these high-risk patients.

LEVEL OF EVIDENCE

IV, retrospective, cohort study.